Marine Algal Ecology of the Hauraki Gulf, New Zealand* This work was undertaken during the tenure of a University of New Zealand Research Fund Fellowship at Auckland University College Botany Department, in 1949 and 1950.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 83, 1955-56, Page 1

Marine Algal Ecology of the Hauraki Gulf, New Zealand* This work was undertaken during the tenure of a University of New Zealand Research Fund Fellowship at Auckland University College Botany Department, in 1949 and 1950. By Vivienne Dellow† Now Mrs. R. M. Cassie. [Received by the Editor, July 30, 1954.] Summary Thirty-four stations in the vicinity of the Hauraki Gulf have been surveyed. In Part I, a discussion of the factors comprising geology, climate and hydrography, special attention is drawn to effects upon intertidal populations of substrate, air and sea temperatures, salinity, pollution, turbidity, tides, currents and wave action. Guiler's (1949) formula has been applied to each station in order to provide an index of the type of wave action. In general accordance with T. A. and Anne Stephenson's (1949) schema for universal zonation on rocky shores, this area can be subdivided into supralittoral, midlittoral and sub- (infra-) littoral zones. A distinct fringe of both supra- and sublittoral zones is recognizable at upper and lower boundaries of the mid-littoral. Part II concerns these divisions, and the groups of species they contain. Twenty-nine “permanent” and 11 seasonal communities are described, and 241 algae have been identified from the Gulf region. In Part III the major features of horizontal and vertical zonation are considered, with particular reference to the factors of substrate and wave action. Five representative vertical sequences are described and figured in detail, and then comparisons are made with reports from other North Island coasts. On the basis of Stephenson's (1947) temperature boundaries, the Hauraki Gulf is classified tentatively as warm temperate. The relative paucity in numbers of algal species is attributed in part to the degree of turbidity and organic pollution, especially in the approaches to the Auckland Harbour. Finally, basic vertical zonation sequences are given for the Gulf under conditions of moderate shelter and extreme wave exposure, and these are compared and contrasted with similar sequences on warm temperate rocky coasts in both Northern and Southern Hemispheres. Part I. Table of Contents Introduction 1 General: Area and Methods 1 Environmental Factors 4      1. Geology 4      2. Climate 6      3. Hydrography 9 Part II. Terminology 21 Biotic Communities 22 Part III. Discussion 40      A. Horizontal Zonation 40      B. Vertical Zonation 49           Relationships With Other North Island Stations 56      C. Comparison With Rocky Coasts Beyond New Zealand 59

1. Geographic Status of the Flora and Fauna 59      2. Relation of Zonation in the Hauraki Gulf to that in Other Countries 62 General Summary and Conclusions 67 Acknowledgments 69 Appendix I: Species List 70 Appendix II: Geographic Range of Dominant Species in the Hauraki Gulf 86 Bibliography 88 Part I. — Introduction and Environmental Factors Introduction The primary object of this work is to present a broad general picture of the most prominent features of littoral zonation on rocky coastlines fringing the Hauraki Gulf. The survey is an extension of a marine ecological study made previously at Narrow Neck, Auckland (Dellow, 1950). The last few years have been increasingly productive in this particular field of research. The year 1949 saw the publication of papers by Williams, Rigg and Miller, T. A. and Anne Stephenson, Evans, Isaac and Guiler. Valuable contributions have come from Australia, for example the broad regional surveys of Dakin, Bennett and Pope (1948), Bennett and Pope (1953) and Newton and Cribb (1951). More intensive studies have been made at Kangaroo Island, South Australia, by Womersley (1947, 1948). The Atlantic coast of North America has been made more familiar through the comprehensive work of T. A. and Anne Stephenson (1950, 1952), while from British coasts has come the recent descriptions Anglesea rocky shores by Lewis (1953). In New Zealand, several accounts of restricted areas have been published. Four of these deal with the Auckland district. Beveridge and Chapman (1950) describe the wave-pounded west coast at Piha, whereas Chapman (1950), Dellow (1950) and Carnahan (1952) each discuss restricted localities in the more sheltered waters of the Hauraki Gulf. The first detailed account of a South Island rocky shore is that of Knox (1953), who surveys the zonation about Taylor's Mistake, Banks Peninsula. General: Area and Methods Covering an area of over 3,250 square kilometres (1,250 square miles), the Hauraki Gulf lies between 36° 13′ and 37° 14′ South Latitude, and between 174° 40′ and 175° 32′ East Longitude. The area includes Waitemata (Auckland) Harbour to the west, the Firth of Thames to the south, and is flanked on the eastern side by the Coromandel Peninsula. Great Barrier Island forms the north-eastern boundary, and Little Barrier Island provides the only land mass between the Gulf and the Pacific Ocean directly northward. To the west the Gulf is bounded by the shores of the mainland (North Auckland Peninsula) as far as Cape Rodney (Fig. 1) Observations were made mostly from March, 1949, to December, 1950. At each station notes were made of the distinctive type of zonation and community complex (Part II, p. 22) in relation to the more obvious environmental factors peculiar to the locality. Some places have received more attention than others, depending on accessibility, time available for studying and local tides and weather

Text-fig. 1. The Hauraki Gulf, New Zealand. Location of Stations 1–34.

at the period of visiting. Records have varied from mere collecting among the drift to mapping of traverses related as accurately as possible to tide levels. Table I indicates the stations examined. Guiler's (1949) formula for wave exposure has been worked out and added for each station (cf. p. 18). Table I. Hauraki Gulf. Wave Exposure at Stations 1–34. Station No. Location. Wave Exposure. Firth of Thames 1. Te Puru Ms W3 D2, Tb2 2. Raukura Point East Coast Mainland Ms W2 D2, Ta2 3. Howick Ms W1 D2, Tb2 4. St. Heliers Bay Ms W2 D1, Tb2 5. Narrow Neck Ms W(0-5), D1, Tb2 6. Arkles Bay Ms W1 D2, Tb2 7. Te Haruhi Bay Ms Ws D2, Tb2 8. Whangaparaoa Heads Mc W3 D2, Ta2 9. Stanmore Bay Ms W2-5 D2, Ta2 10. Orewa Ms W2-6 D3, Ta2 11. Leigh Cove Ms W1 D3, Tb2 12. Cape Rodney Islands* Excluding Great Barrier. Me W2 D3, Ta2 13. Kawau Ms W2 D2, Tb2 14. Rangitoto (except north coast) Ms W1-3 D2, Tb2 15. Noises—Otata Waiheke Me W3 D3, Ta2(3) 16. Surfdale Ms W3 D2, Tb2 17. Arran Mc W2-4 D2, Tb2 18. Anita Bay Mc W2-5 D3, Ta2 19. Palm Beach Mc W2-5 D2, Ta2 20. Oneroa Mc W2-5 D3, Ta2 21. Shag Rock (Tarakihi) Mc W3-5 D2, Ta2(3) 22. Gannet Rock (Horuhoru) Little Barrier Mc W3-5 D3, Ta2(3) 23. The Pinnacles Mc W3-5 D3, Ta3 24. Ti Titoki Flat Mc W2-5 D3, Ta2 25. Pohutukawa Flat Coromandel Peninsula Mc W2-5 D2, Ta2 26. Coromandel Harbour Ms W1-2 D1, Tb1 27. Long Beach Ms W1-3 D2, Tb2 28. Fletchers Bay Mc W2-4 D2, Ta2 29. Sugar Loaf Rocks Mc W2-5 D3, Ta3 30. Whitianga (including Wha Wha) Great Barrier (Mc W2-5 D3, Ta2) 31. Whangaparapara Ms W1 D2, Tb1(2) 32. Port Fitzroy Mc W1-3 D1, Tb2 33. Needles Point Mc W3-6 D4, Ta3 34. Oruawharo Bay Mc W3-6 D4, Ta3 Environmental Factors 1. Geology The physical nature of the rock surface in the intertidal region has a certain selective value regarding the presence or absence of a given community—a feature amply illustrated by zonation patterns in different geological regions of

Text-fig. 2. The Hauraki Gulf: Contours of the sea bed in fathoms. (Map by R. M. Cassie.) the Gulf. In fact, the area divides itself up conveniently into a number of sectors according to the general nature of the substrate. The principal rock types present are greywackes and argillites, andesitic conglomerates and breccias, sandstone and grit, and finally a few local areas of volcanic basalt. Historically the area is an interesting one. Details of the sequence in past ages are beyond the scope of this work, and have been largely made known through the careful work of local geologists. For further information the reader is referred to Fraser and Adams (1907), Bartrum (1921), Bartrum and Turner (1929), Ferrar (1934), Hamilton (1937), and Searle (1948).

Briefly, the highlights of local geological history are these. The northern part of New Zealand underwent three submergences: the first in Mesozoic times, flood waters depositing argillites and greywackes. With the next flooding came limestone beds in the Cretaceous and early Tertiary. In the final Mid-Tertiary submergence sandstones and mudstones were formed. A series of blocks breaks up the mainland as it stands to-day. The Coromandel Peninsula is an elevated block composed mainly of the ancient greywackes that underly the whole area. On the other side of the Gulf the Hunua block consists of sandstones, limestones and coals, as well as greywackes. These two blocks are separated by the low-lying Hauraki Plains, south of the Firth of Thames. The Auckland block comprises a series of terraces formed by the old Waitemata River as far back as the Waitakere Ranges. Limestone outcrops in it are rare. The deeply indented coastline and many islands of the Hauraki Gulf came into being as a result of the most recent (Post-Pleistocene) downward movement of the of the land-mass and consequent flooding of low-lying valleys and river systems by the sea (Searle, 1948, p. 34). Rangitoto Island was formed even later by volcanic activity along with other basaltic lava districts about Auckland (e.g., Milford, North Head). Over the past few thousand years there have been no marked changes in land-sea level, any modifying effects having been caused by erosion. Soft sandstone cliffs have retreated at a rapid rate under the continual impact of direct, though gentle waves, and by the action of rain and wind. Thus there remain wide shore platforms as far as these cliffs extend, in contrast with the more steeply shelving coastlines of the firmer greywacke landmasses. 2. Climate New Zealand's climate falls naturally into the category of insular or oceanic. Its weather is controlled by a series of moving anti-cyclones and intervening troughs of low pressure, usually accompanied by cold fronts associated with depressions passing to the south. Duration of fine weather is mostly more prolonged in the north and east. Climatically, the Hauraki Gulf region is relatively homogeneous. On Thornthwaite's system of climatic classification, the whole area comes into the category of Bb'r—i.e., a humid, mesothermal forest climate with P—E and T—E indices ranging from 64 to 127 (Garnier, 1950, pp. 88–90). Fluctuations in small sectors result from differing amounts of rainfall and strength of the prevailing wind, both of these depending on aspect and on local variation in topography. Apart from detailed records made at Auckland there are a number of subordinate climatological stations which supply daily (and sometimes nightly) information to the main meteorological centre at Musick Point. These stations are located at Thames, Coromandel, Kawau, Little Barrier and Port Fitzroy. Just beyond the limits of the Gulf are two further stations, at Moko Hinau Island in the north and to east of Cape Colville at Cuvier Island. Records are also available from several rainfall stations, including those at Nagle Cove (Great Barrier), Whitianga (Mercury Bay) and Rocky Bay (Waiheke). (a) Wind Winds are variable, but in common with most of the country, westerlies (between N. W. and S. W.) are the most frequent. In eastern districts, where protection is afforded by mountain or hill ranges, winds are more variable and

sea breezes tend to predominate in summer. Onshore gales accompanied by widespread warm-frontal rain are associated with easterly and north-easterly winds. Between 35° and 40° S. and 170–175° E. the average number of days on which gales of Force 7 or over on the Beaufort Scale have occurred is as follows:— Month. Days January 4 February 2 March 2 April 1 May 6 June 7 July 7 August 9 September 5 October 3 November 3 December 1 Total 50 These figures are averaged from recordings taken at sea over a period of 49 years (N.Z. Pilot, 1946, p. 31). Protected as they are by the mainland to the west, the waters of the Gulf are seldom whipped up to the same degree as at Piha and other west coast localities; but an occasional gale from the east or north-east can cause considerable damage and dislodge great quantities of the algal populations inhabiting the sublittoral and its fringe. Table II indicates the direction and % frequency during different seasons at Auckland. Table II. Wind Direction Percentage Frequencies at Auckland. (After Garnier, 1950, p. 49.) Season N. N.E. E. S.E. S. S.W. W. N.W. Calm Summer (Dec.–Feb.) 7 20 7 5 11 29 10 9 1 Autumn (Mar.–May) 6 15 9 10 14 24 10 9 2 Winter (June–Aug.) 5 12 6 9 14 25 14 11 4 Spring (Sept.-Nov.) 7 17 4 4 8 32 16 11 1 (b) Rainfall A winter maximum is quite pronounced about and north of the Gulf (Fig. 3), where annual precipitation varies between 76 and 127 cm. Exceptions are provided by Coromandel Peninsula and the Cape Rodney district, where there is usually a fall of more than 127 cm. (50 inches) per annum. * Figures supplied through courtesy of the Director of Meteorological Services, Wellington. Thames average for 5 years only. Annual rainfall averages have been calculated for several stations in the Gulf:— Cm. No. of Rain Days Auckland 124.82 183 Thames 123.95 176 Rocky Bay (Warheke) 112.07 155 Whitianga (Mercury Bay) 160.68 — Nagle Cove (Gt. Barrier. N. W.) 123.47 166 Little Barrier 149.63 158 (A rain day is taken as one on which there is a fall of at least 0.005 inches.) The figures are not strictly comparable since they are averaged from differing numbers of years, but they serve to indicate that on Waiheke Island, at least, both amount and distribution of rainfall is slightly less than at Auckland. At Little Barrier Island there is a slightly greater total rainfall per annum, but more rain falls on fewer rain days (cf. Hamilton, 1937, p. 31). Although statistical proof is lacking, there does seem to be a difference in the total amount of precipitation

between the northern and southern ends of Great Barrier Island. Showers pass more frequently over the southern end, having crossed Little Barrier and striking the Coromandel Ranges from the north-west. Text-fig. 3. Auckland. Annual average rainfall in centimetres per month, and number of rain days. (c) Humidity, Sunshine In most Auckland districts relative humidity is high, records taken at 9.30 a.m. showing an annual average range of 75–82%. Seasonal variation is indicated in the following extreme percentages for Auckland (Mirams, Unpub.): Maximum R.H. Minimum R.H. Winter 99% 60% Spring 98% 55% Summer 94% 45% Autumn 92% 54% Fogs are surprisingly infrequent except in land-locked estuaries. Accurate information is lacking, but there are seldom more than 5 days per annum with fog, generally on still mornings in early winter. Mists clear as a rule about 11.0 a.m. or mid-day. January is the sunniest month in Auckland, with an average of 227.7 hours. June has the least sunshine, the average being 122.2 hours (Fig. 4). The yearly total of 2,058.2 is quite a high one in comparison with most other New Zealand districts. (d) Air Temperature The predominantly maritime climate of the North Auckland Peninsula and the protection of the Gulf by the mainland to the east, south and west greatly lessens the occurrence of extreme low temperatures. In fact, the geographic pattern of the coastline is followed closely by the mean annual isotherm of 14 4° C. (Garnier, 1950, p. 61, Fig. 4). This isotherm is 1.1° C. higher than the mean for the corresponding coastline west of the North Auckland Peninsula, which is exposed to the full force of prevailing westerlies. The average range of variation is between a mean lowest minimum of 2.8° C. and a mean highest maximum of 27.1° C. (Fig. 5). The extreme highest and lowest temperatures yet recorded

Text-fig. 4. Auckland. Average monthly relative humidity and number of hours sunshine. at Auckland are 32.3° C. and 0.0° C. respectively. When prevailing winds are onshore, February may be a warmer month than January, but in most eastern districts January is the warmest month. Coldest temperatures occur in July. Ground frosts are exceptional in coastal parts of the Auckland district, rarely more than three occurring in a year. However, a heavy frost in winter, 1951. was sufficient to kill mangrove (Avicennia) plants at Henderson, in the Upper Waitemata Harbour (V. J. Chapman, personal communication). Hydrography. Sea temperatures and ocean currents. (a) Currents The main ocean currents which affect the northern half of the North Island are the South Equatorial Current, the Trade Wind Drift, and the East Cape Current. One arm of the South Equatorial Current flows into the East Australian, or Notonectian, Current. The latter supposedly follows a path across the Tasman in the direction of North Cape, which it rounds and affects the eastern shores of the North Auckland Peninsula. To the south of the Equatorial Current is the Trade Wind Drift, backed by the so-called south-east trade winds. It is possible that the East Cape Current (running south in a line parallel with the coast from East Cape to Wellington) forms an extension of the Trade Wind Drift. The Hauraki Gulf is well to the north of the zone of convergence of subtropical and subantarctic waters (the latter carried northward by the West Wind Drift). One part of this mixed warm and cold water passes up the west coast of the South Island and through Cook Strait; the other flows up the east coast. A difference of more than 5° C. has been recorded on either side of the zone. Evidence from drift bottles accumulated from the work of H. C. Russell between 1894 and 1902 (Dell, 1952, p. 86) upholds the views of present workers

Text-fig. 5. Auckland. Monthly average air temperatures. 1. Absolute highest maximum. 2. Mean highest maximum. 3. Mean lowest minimum. 4. Absolute lowest minimum. concerning the main current systems affecting New Zealand shores. It was shown that such bottles could travel over 6,400 kilometres, averaging a speed of 13 km. per day (ranging from 2.2 to 21.3 km. per day according to wind strength and direction). The biological implications are important, for these results show that living organisms can travel from South America to New Zealand or Australia in under three years. It is doubtful, however, that algal germlings or fragments would survive for so long a period and still be in a sufficiently healthy state to compete successfully for establishment with those forms already dominating on Australasian shores. (b) Sea Temperatures A lag of about a month behind air temperatures is responsible for the highest records occurring in February and the lowest in August. Minimum records off the east coast of the North Island are appreciably higher than those of the west. From August there is a gradual increase, differences between east and west coasts becoming negligible. The warmest months are from January to March, during which time sea temperatures remain almost constant. Throughout the years 1949 and 1950 when the field work of this survey was carried out, sea temperatures were in general 1–2° C. higher than normal, as indicated by M.O.M. (Meteorological Office Memoirs) figures. These warmer temperatures were most evident in the north Tasman and off the east coast of both North and South Islands. The increase in the north Tasman may be attributed to a stronger and more easterly flow of the East Australian Current. Warmer water on the east coast appeared to be due to a more southerly penetration of the East Cape Current. Despite their derivation from records of ships over a considerable period of years, M.O.M. charts of mean currents do not present a uniform pattern either in the Tasman or to the east of New Zealand; but data assembled for the year 1949 indicate that waters carried in a westerly direction by trade winds are deflected

to the south as they approach the east coast of the North Island. Here warm water from the Tasman was not in evidence during 1949, suggesting that the East Australian Current turned back on itself and continued north in an anticlockwise direction to rejoin the parent current. The Hauraki Gulf lies between the February and August sea isotherms of 20.0 and 13.3–14.4° C. The average annual range therefore does not exceed 6.7° C. The following figures (from unpublished records at the Geophysical Observatory, Wellington) have been averaged from surface temperature data collected by coastal vessels between 36 and 37° S. Hauraki Gulf East of Coromandel Penin. °C. °C. January 20.6 20.6 February 20.0 20.6 March 20.0 20.0 April 19.4 18.9 May 18.3 17.8 June 17.2 16.7 July 15.0 15.6 August 15.0 15.6 September 15.0 15.0 October 16.1 17.2 November 17.2 17.2 December 19.2 19 2 These figures are considered to be fairly representative, but the margin of error must be considerable since when spot readings are made, no account is Text-fig. 6. Monthly average sea surface temperatures. 1935–1938 Auckland Harbour — — Coromandel Harbour…………

taken of time of day, and local variation in such factors as cloud, sunshine and wind. Detailed records for waters in the Gulf have not been assembled previously in any systematic form of monthly averages. Under the direction of the late W. M. Jones (Geophysical Observatory, Wellington) a survey has been made recently of surface and deep water temperatures. These figures are not available for security reasons. A set of published figures appears in a Marine Department report on Fisheries (1938, p. 40) tabulated from the 4-year period 1935–1938. The graphs in Figure 6 illustrate the essential similarity between monthly averages for Auckland and Coromandel Harbours. A number of inshore records were made by the writer in a depth of 0.5 to 1.0 metre at Clifton Beach, north of Narrow Neck (Table III). These were not made at frequent enough intervals to be of much value, although they serve to indicate sudden drops between May and June, after which months records remained consistently low until mid-September. Making no allowance for local weather changes, highest sea temperatures occurred between 3.00 and 5.00 p.m. Table III. Air and Sea Temperatures Inshore at Low Water, Clifton Beach. Date. Air° C. Av. Sea° C. Av. 3.4.49 17.8 18.9 16.4.49 18.5 17.1 18.8 17.3 25.4.49 15.1 14.2 1.5.49 17.1 17.0 9.5.49 14.8 16.7 15.6 16.4 29.5.49 18.0 16.5 8.6.49 14.0 15.0 20.6.49 11.7 12.9 12.2 13.6 3.7.49 11.5 12.8 9.7.49 11.5 11.5 13.0 12.9 13.8.49 14.0 13.0 21.8.49 12.4 13.2 12.5 12.8 2.9.49 13.1 12.8 4.9.49 15.4 15.2 14.4 14.9 21.9.49 17.0 17.5 22.1.50 23.0 21.0 30.1.50 20.9 22.0 21.8 21.4 Much work remains to be done on the problem daily, monthly, and annual temperature variation in the Hauraki Gulf. From the meagre records available, the lowest sea temperature was 12.2° C. (Clifton Beach, 20.6.49) and the highest 23.5° C. (Narrow Neck, 23.1.50). These figures probably do not represent absolute minima and maxima. Of considerable significance in the intertidal region is the more extreme heating and cooling of exposed rock and shallow pools subject to strong illumination. The highest pool temperature so far recorded in the Gulf is 32° C., in a small, high level pool at Narrow Neck (Ambler and Chapman, 1950, Fig. 8). An abnormally high maximum of 38° C. was noted on exposed high-water boulders at Little Barrier (Station 24) on October 23, 1949. This was more than twice the corresponding sea temperature, which was only 17.8° C. On the same day at an exceptionally low spring tide the temperature among holdfasts of Ulva, Glossophora, Carpophyllum, Myriogramme and Plocamium was 29.1° C. The plants were dying; some were rotten, emitting the characteristic smell of decaying weed

that has been collected for some time. This was presumably the result of high air temperatures coinciding with low spring tides, absence of wind and low sea temperatures. (c) Salinity Two salinity surveys have been carried out in recent years in the Hauraki Gulf: one by Fuller (1953), the other by Jones (Unpub., Geophysical Observatory, Wellington). Fuller's work was done mainly during 1949 and 1950 as part of a plankton survey, his values ranging from 34.87% to 35.70%. According to Fuller, there are two distinct plankton populations in the Hauraki Gulf: that of inshore waters, and that of oceanic waters in the outer region. This latter has two seasonal components, being dominated by salps (Thalia, Salpa spp.) in summer and by chaetognaths (Sagitta spp.) in winter. These are associated with waters of higher salinity (above 35.50%), whereas the salps reappear with decreasing salinity. Fuller suggests that the observed seasonal variation in plankton and salinity may be connected in some way with variation in flow of the Notonectian Current. Salinity values were found to be lower in more southerly regions of the Gulf, and this is in general agreement with the figures obtained by Jones for November/December, 1951, and July, 1952. The latter in a personal communication to the writer preferred to interpret his lower values off Cape Colville in November/December, 1951, as due to run-off of rainwater from the Coromandel Peninsula, since they did not extend south or north. Low figures further south in July were correlated with the northward outflow of the Waihon and Piako Rivers. Extremes in July, 1952, ranging from 34.27 to 35.55%, represent about a 4% change in salinity. November/December extremes were 34.92 to 35.46%. Variation in salinities at mouths of streams and rivers has not been studied in these waters. The esturaine components (Day, 1951) remain to be analysed, the problem being beyond the scope of this work. (d) pH, Oxygen Concentration Hounsell (1935, p. 269) notes a pH range in Auckland Harbour of 8.25–8.37. The importance of pH as a limiting factor is increased in tide pools where sudden fluctuations may exert an adverse influence on steno-ionic organisms. Ambler and Chapman (1950, p. 405) report an increase from 8.0 to 9.0 within an hour in a small, high-tidal pool at Narrow Neck, populated exclusively by Enteromorpha. Values are expected to fluctuate according to pool volume, plant-animal ratio, and hence balance between photosynthesis and respiration. The same workers note a variation in oxygen content from 7.16 to 13.10 cc. per litre—i.e., the pools are supersaturated at times. A diurnal and seasonal variation in Co2-O2 concentration will occur under average pool conditions where plants are present, since photosynthesis occurs only in sunlight. One may compare in this connection the work of Nicol (1935, p. 240) who found in pools of a Scottish salt marsh that lowest values of pH and O2 occurred in early morning. Maxima were reached by early afternoon, when O2 was saturated up to 200%. (e) Pollution There are seven sewage outfalls within the outer boundaries of Auckland Harbour. These are located at Orakei, Northcote, North Head, Narrow Neck, St. Leonard's Point, Thorn's Bay (Milford) and east of the inner Harbour entrance on Motuihi Island The chief effects of pollution on seawater are increases in

(a) turbidity, due to the large amount of material in suspension; (b) the percentage of free and albuminoid ammonia; (c) concentration of nitrates; (d) bacterial content—mostly coliform types (Hounsell, 1935). Sewage pollution of the Auckland Harbour has been a controversial subject over the past few years. Recently a number of biochemical and microbiological tests have been made in connection with the Drainage Commission enquiry. Biochemical tests were carried out by R. Hicks (Auckland Metropolitan Drainage Board); and microbiological analyses were made under the direction of K. Griffin (Dominion Laboratory, Auckland). Wallace and Newman (1953a, b) have published the results of a bacteriological survey of Auckland Harbour. Seawater samples are classified by them in four categories, according to the M.P.N. (most probable number) of coliform organisms present per 100 millilitres. Their Figure 1 amply illustrates the extent of pollution, which is seen to be greatest in two main areas, irrespective of wind and tide (a) between Orakei and St. Helier's Bay, (b) in the Rangitoto Channel, for nearly a mile (c. 1 kilometre) off the North Shore, and 2–3 miles (3–5 kilometres) north from Narrow Neck. The Orakei field results from the discharge of crude sewage from a city population of over 220,000, and is further amplified by the North Head outfall. Waters east of the North Shore are polluted from the outfalls at Narrow Neck, St. Leonards Point and Thorns Bay. Up to 350 M.P.N. coli per 100 ml. are recorded in nearly all the seawater samples from these areas. Under westerly conditions of wind and tide the southern shores of Rangitoto may be kept in a more or less continual state of pollution, from either the Orakei or the North Shore field, or from both. East of St. Heliers Bay the beaches are relatively unpolluted, although wind is an important factor controlling the degree of movement of the sewage fields, more important, in fact, than tide. The fact that the diattom count increases with distance from the source of pollution, provided that wind force is less than 6, has also been established by Wallace and Newman. Effects of Pollution on Intertidal Populations From a recent study at Christchurch, Bruce (Unpub.) reports a drastic change in population of plants since 1929, whereas the animal population has been more static. Growth of Ulva and Scytothamnus (now known to be Gracilaria) has been promoted by absorption of nitrogen as saline ammonia and nitrates supplied by sewage products. Ulva and Euglena are regarded as indicators of sewage pollution. On the other hand their absence is not proof that the area of mud is free from faecal organisms. Other factors which condition the growth of such indicators must also be favourable. The decrease in Zostera since 1929 may be due to other causes, since it can tolerate a considerable amount of pollution. How far Bruce's findings can be applied to the Hauraki Gulf is not known. In May, 1949, however, vast quantities of Ulva latissima were found growing of washed up and decaying round the margins of Coromandel Harbour, which is largely occupied by an extensive mudflat. It remains to be seen whether the abundance of this species is to be correlated directly with sewage pollution from Coromandel township or with other local factors. About St. Leonards Point and Bastion Reef (west of St. Heliers), both heavily polluted localities, there are dense communities of Mytilus canaliculus and the

polychaet Pomatoceros coeruleus (Plate 1, Fig. 1). The latter has increased in abundance appreciably over the past four years at St. Leonards Point. Saxostrea is able to grow where there is considerable pollution, as evidenced by bacterial counts of their flesh and shell water. The ability of faecal coli to multiply inside the oyster shell indicates the economic and social importance of harvesting oysters from relatively unpolluted waters. This point is also emphasized by Wallace and Newman (1953a, p. 522). Growth of lower midlittoral and sublittoral algae at St. Leonards Point must be affected in some degree by the increase in nitrates and ammonia. Nevertheless there does not seem to be a marked change in species composition from nearby reefs, for nearly all the dominants from different belts are present, including Corallina, Codium adhaerens var. Convolutum, Laurencia, Gelidium caulacantheum, Carpophyllum plumosum and C. mashalocarpum. Glossophora grows more luxuriantly than at Narrow Neck on the main reef; like Gracilaria it can evidently tolerate considerable pollution. (f) Turbidity, Light Penetration The amount of suspended material in the Gulf varies greatly from place to place. In the clear, oceanic waters circulating about exposed coasts to north and east it is negligible—in sheltered inlets and harbours, and about the mouths of sewers and estuaries, it is greatly increased. Apart from sewage outfalls, the suspended matter may have (a) been carried towards the land by wind and sea currents; (b) been transported from the land by rivers and streams; or (c) originated from estuary beds (Day, 1951, p. 60). According to Bassindale (1943), turbid zones of an estuary are regulated by its shape and current system. The most turbid zones are those where tide currents are strongest; but wind may have an opposite effect, causing a silting up at the margins. It is this latter effect which most concerns intertidal organisms, since they are generally marginal in location. The question of light penetration is related largely to that of turbidity. Isolated spot observations have been recorded by lowering a Secchi disc and noting the depth at which it becomes invisible from the surface. The figures in Table IV give some indication of the type of condition to be met with in different parts of the Gulf. Table IV. Light Penetration as Recorded by a Secchi Disc in the Hauraki Gulf. Locality Date Weather Depth at Site Disc Visible to: Crab Island (Narrow Neck) 22.1.50 Fair 6.2′ (1.8m.) 4.1′ (1.2m.) Sugar Loaf Rocks (N.E. Coromandel) 17.5.50 Dull 12.0′ (3.7m.) 10.3′ (3.1m.) Ti Titoki Flat (Little Barrier) 17.10.49 Clear 25.0′ (7.6m.) 25.0′ (7.6m.) Katherine Bay (Great Barrier) 28.50 Clear 180.0′ (54.9m.) 80.5′ (24.4m.) The actual depth of penetration varies in the same position with the amount of sunshine or cloud, the angle of incidence of the sun's rays, and also the state of turbulence and turbidity of the water. Near the coast, and particularly on reef and pool fringes, a mechanical barrier more sudden in its limiting effect on light penetration is provided by the dense, opaque fronds of large brown algae. At Narrow Neck, for instance, the disc cut out at 1.5ft. (0.5 metre) below the surface, which was layered with broad fronds of Ecklonia radiata and bushy

trailers of Corpophyllum plumosum. Beyond the reach of the fronds the disc was still visible at more than twice this depth (4.0 ft.). (g) Tides i. Tidal Streams The direction of tidal streams at the mouth of the Hauraki Gulf is not known accurately. A difference of up to three hours may occur between the change of stream direction and the time of high or low water, and results in the offshore tidal stream flowing at its maximum velocity at the time of slack water inshore. On the eastern coast of the North Island the tidal stream sets northward with a rising tide and southward with a falling tide. Within the Gulf, as might be expected, the situation is reversed, a flood tide flowing south (N.Z. Pilot, 1946, p. 165). Between Cape Colville and the southern end of Great Barrier rising streams set westward, and falling streams eastward, at spring tide reaching a speed of up to 3 knots. A rising stream continues along the south-west coast of Great Barrier in a northerly direction as far as False Head,* See Admnalty Chart No. 2543 for details of localities mentioned in passing in the text. where it is met by the stream entering the Gulf from the north. There is thus a confusion of rippling waters even in calm weather off False Head and also off Wellington Head.* East of Great Barrier the tidal streams are relatively weak. About Kawau Island the stream attains a rate of 2–3½ knots at springs through the North Channel* but decreases to about 1 knot between Kawau Point* (S.E.) and Flat Rock.* In Whangaparaoa Passage* (between Tiri Tiri Island and Whangaparaoa Peninsula) the stream, still rising to the south and ebbing northwards, seldom exceeds 1–1½ knots. For the Auckland Harbour area spring and neap velocities before and after high water are given in detail on Admiralty Charts 1896, 3797, 2543 and 1212. Here the stream is reduced to a maximum of 0.5 knot. The tide flows in and out of the harbour via Tamaki Strait,* which separates Waiheke Island from the mainland. In its narrowest parts a velocity of 2 knots may be reached, but in the centre of the strait the stream is imperceptible. Coming down the Coromandel Peninsula the tide sets about 2 miles north of the Motu Kawao* group of islands. Rate of flow is pronounced off the Moehau quarries on the mainland, 5 miles south of Jackson's Bay.* At this point there is apparently a counter-movement of the stream, which flows in a circular fashion to the north-west on flood. In the main, however, the south-north direction of the flood and ebb is apparent as far south in the Firth of Thames as the Waikawau River.* Inside the lagoon-like expanse of Coromandel Harbour the ebb and flow is to west and east respectively, westerly winds making tides up to half-an-hour earlier, easterlies delaying them for half an hour. In Mercury Bay, on the east coast of the Coromandel Peninsula, the tidal stream is usually no greater than 0.3 knot. West of Shakespeare Cliff the stream has a clockwise, rotary motion during ebb, more obvious in the shallow, northern end of Buffalo Beach, where large quantities of drifting weed and debris are frequently east ashore. Evidence for stronger currents in the Gulf during flood tide comes from a letter written to the Auckland Star on 9.9.50 by T. McKnight, about harbour

pollution. It is stated that during 1913 carcases of 33 dead horses were dumped between Tiri Tiri and Great Barrier Islands. Within three days many carcases had drifted right back on to beaches in the Auckland Harbour, including St. Heliers Bay. Earlier, in 1911, a damaged cargo of mutton was dumped near Great Barrier. It took only a few days for this to drift as far back as Motuihi and Browns Island. These facts are not conclusive in themselves without accompanying data on wind force and direction, as well as accurate tidal information. Nevertheless a north-easterly gale has been known to bring ashore at Glendowie (east of St. Heliers) specimens of Carpophyllum elongatum, which is confined in the Gulf to small islands west of Port Fitzroy and to the extreme north-east tip of Coromandel Penisula. ii. Tide Levels In any water mass partly enclosed by land considerable variations in both time and height of the tide may be expected to occur. Many workers on intertidal ecology have found from experience that, owing to a frequent deviation of tidal behaviour from the normal for the nearest port of reference, each locality needs to be studied on its own. In the Hauraki Gulf extreme spring tides range from about 14. Oft. in Coromandel Harbour to about 8 Oft. at Cuvier Island. Taking Auckland as the standard port of reference, the following figures taken from the Nautical Almanac (1950) give the ratio of the tide ranges for localities where it is known: Auckland 1.00 Coromandel 1.19 Tryphena 0.74 Cuvier Island 0.70 Mercury Bay 0.64 The writer's brief observations of tidal behaviour in the Gulf (Table V) varied from that made over a weekly period (Station 24) to those over a single 6-hourly rise or fall of the tide (Stations 17, 30, 32). Table V. Tidal Observations in the Hauiaki Gulf. Station Tide Range in Feet No. Location Date −Splash +Splash Predicted Spring or Neap 17 1.9.50 8.1 8.4 7.9 (Auckland) Spring 24 Ti Titoki Flat 17.10.49 4.7 5.0 4.0 (Tryphena) Neap 24 Ti Titoki Flat 24.10.49 6.5 8.0 8.0 (Tryphena) Spring 27 Long Beach 18.5.49 6.3 6.3 9.1 (Coromandel) Neap 28 Fletchers Bay 17.5.50 4.0 5.2 5.1 (Cuvier Is.) Neap 30 Whitianga 15.5.49 6.6 7.0 6.8 (Mercury Bay) Spring 32 Port Fitzroy 6.4.50 7.3 7.5 8.1 (Tryphena) Spring In the above table the Coromandel Harbour figures are obviously not applicable to Long Beach, which is only 5 miles away, but is situated on the open coast. Results from Ti Titoki Flat, Little Barrier, also appear anomalous in comparison with the expected ranges at Tryphena. The neap range is greater but the spring range is smaller, if splash is not taken into account. The splash zone (Colman, 1933) was particularly hard to estimate here owing to the broken surface topography occasioned by the loose stones and boulders. Figures from Fletchers Bay agree substantially with the expected record for Cuvier Island; likewise Whitianga with Mercury Bay. and Arran with Auckland. The range at Port Fitzroy appears on superficial examination to be slightly less than at Tryphena,

but the record cannot be accepted as significant in the absence of a synoptic figure at the latter port. Tide watches were confined to days when wind and waves were at a minimum, so that differences in water level could be judged as accurately as possible. Half-hourly records were kept and the vertical sequence of species and communities was established as each became uncovered, after the method of Evans (1947, p. 281). At Stations 17 and 32, wooden jetties provided vertical faces easy of access on which to make measurements. In other localities observations had to be made directly on rocky headlands. All watches began at high water, for the practical reason that the highest water mark shows quite clearly in fine weather against the dried out line of demarcation of the upper midlittoral or supralittoral, whereas the exact line of low water mark is often hard to ascertain. Actual high water mark was taken as the mean between maximum and minimum swell. (h) Wave Action The effects of this factor are perhaps more obvious that any others in moulding the different types of community complex (Part II, p. 22). It is an extremely difficult factor to express in quantitative terms. Various attempts have been made to evaluate an exposure factor (e.g., those of Fischer-Piette, 1932,* Reference in Moore, 1935, pp. 280–281. Moore, 1935, and Guiler, 1949). Fischer-Piette used the presence of Fucaceae as indicators of the degree of exposure to, or shelter from, wave action. But as Guiler remarks, the absence of belts occupied by the Northern Hemisphere fucoids or their equivalents in these southern latitudes precludes the use of Fischer-Piette's scheme in any universal sens. As part of a study of the environment affecting Balanus balanoides Moore (loc. cit. p. 280) defined an exposure factor which is equal to the number of days per 100 days that any wind blows into an exposed aperture with a seawards opening measured at a distance of half a mile. The chief drawback in the application of this scheme to the Hauraki Gulf is the lack of local information on wind direction. Guiler's formula (loc. cit. pp. 170–171) aims at being comprehensive without including too many complications, and, save for wind strength, without being quantitative. Provided that the reader is acquainted with the intended significance of each symbol,‡ Formula to express wave exposure, as stated by Guiler (1949): it is possible that the formula may be applied to other coasts, and so be a means of establishing a uniform standard for description of this factor. M (marine) o, oceanic. c, continental shelf. s, shallow waters of less than 10 fathoms. W (wind) The force of wind given in Beaufort Scale. This is given as an absolute figure for the time of observation on as a range encountered over 1 year (in brackets). D (distance) 0, less than 100 yards. 1, 100 yards to 1 mile. 2, 1 mile to 20 miles. 3, 20 miles to 100 miles. 4, greater than 100 miles. T (topographic) a, exposed coast; 3, fully exposed surfaces. 2, semi-exposed surfaces. 1, fully protected surfaces.

b, sheltered coast; 3, exposed surfaces. 2, semi-exposed surfaces. 1, fully protected surfaces. Guiler realises that there must be a wide margin in estimates according to the personal opinions of different workers. A protected situation on his view is one where waves never exceed 6 inches (5 cm.) in height. It is almost impossible to give a precise definition here, since in the present writer's experience one spot may come under the category of being protected when wind is off the land, and the same place would be classified as semi- or even fully exposed when a gale blows from the opposite direction. From this point of view Moore's exposure factor based on percentage of wind direction would be more satisfactory. Despite these drawbacks, Guiler's scheme is considered suitable for application here (Table I). The Beaufort Scale is given as that estimated at the time of examination of each locality. Where a range of variation in wind strength is known, figures are not given in brackets since they do not represent an annual range (except for Narrow Neck). Further, most visits were made under comparatively favourable weather conditions, and so maximum wind strength is not known. From a quick glance at a given formula it is not always easy to recall which figure represents which factor. This suggests an improvement to Guiler's setting out of the formula by inserting the factor symbols M, W, D and T before their respective figures, as in the formulae for Hauraki Gulf stations in Table I. Part II.—Terminology and Biotic Communities Terminology The nature and status of the various terms in most general use to cater for the requirements of rocky shore ecology are still the subject of much controversy. After consideration of many coasts in both hemispheres, T. A. and Anne Stephenson (1949) proposed a fresh series of basic terms to replace their former (1943, 1947) suggestions. These, they hope, may prove to have some degree of universal application. For their previous Littorina and balanoid zones and sublittoral fringe they would now substitute the midlittoral zone which separates the supralittoral from the infralittoral zone. Womersley and Edmonds (1952), on the other hand, argue that the Stephensons' schema requires modification in respect to the South Australian rocky coasts. As far as New Zealand is concerned, Chapman and Trevarthen (1952) have re-affirmed, and the writer also holds this opinion, that the Stephensons' scheme is more readily applicable than any other yet proposed to categorize its hard rock coastline. This scheme, which has already been accepted favourably by other workers (e.g., Guiler, 1949, Lewis, 1953, Knox, 1953) can be tested in the light of local behaviour of intertidal organisms. 1. Supralittoral Zone The supralittoral zone appears to be a valid entity in those parts of the Hauraki Gulf where cliffs tower above the midlittoral. However, in places where land communities advance over low-lying areas to a point directly above E.H.W.S. it may be eliminated. Against this it can be argued that such usually happens only behind sandy beaches or mudflats where, as Chapman and Trevarthen (loc. cit.) have emphasized, zonation is governed largely by a different combination of factors. Takapuna Reef, north of Narrow Neck, provides an instance where there is no true supralittoral zone.

The latter is essentially a maritime zone, not subject to any direct tidal influence, liable to undergo severe drying out in a non-rainy season, but the recipient of sporadic to fairly continual drenching by wind-blown spray. In the Hauraki Gulf plants and animals are absent or poorly represented on many cliff faces, most notably those easily strata of Waitemata Sandstone shores. Elsewhere the zone supports a conspicuous cover of grey and yellow lichens, and it is the latter which generally delimits its lower boundary. Chapman and Trevarthen (1952, p. 203) would include the greyish-white band of lichens in the supralittoral fringe. That such growths, may occur at times below E.H.W.S. is certain, but seldom or never do the grey species occur in the same abundance as at supra-tidal levels. 2. Supralittoral Fringe There can be no question as to the separate existence of this zone. In the Auckland district, Melaraphe oliveri and less frequently M. cincta are the physiognomic dominants within its limits. The occasions when the littorinids migrate many feet up beyond direct tidal influence are few in number, when compared with the many stations where Melaraphe was not observed any distance above E.H.W.S. In the majority of cases where it does range above this level, the influence of direct wave-splash rather than of wind-blown spray appears to be responsible. This restriction is conditioned by the generally calmer, less churned-up waters inside the Gulf. Predominance of Lichina and, locally, of Myxophyceae is also a feature of the region (cf. Chapman and Trevarthen, loc. cit.). 3. Midlittoral Zone The upper limit of barnacles in quantity is a reasonably reliable indication of the upper boundary of the midlittoral on these shores. In their (1949) definition, the Stephesons would regard the lower midlittoral boundary as marked by “the upper limit of the zone below.” Supposing that the next zone is a mixed algal zone (Chapman, 1950), as it frequently happens to be in both sheltered and exposed waters of the Hauraki Gulf and in other parts of the North Island (personal observation), then the midlittoral cannot be taken to coincide with Oliver's (1923) definition of the littoral as that part of the shore between highest wash and lowest level of spring tides. The mixed algal zone is exposed by all spring tides, and at least partly uncovered by larger neap tides. Further, confusion may result from a loose application of the term “zone”. For instance, Dakin, Bennett and Pope (1948) regard Pyura as forming a separate “zone” in the “littoral-sublittoral” fringe. In the Gulf waters the “zone”, or perferably “belt”, below the barancles may be Saxostrea, Pomatoceros, Xiphophora, Corallina or other short algal turf, or else crustaceous Lithothamina. It is a moot point whether any of the above (except Saxostrea) should be included in the lowest midlittoral zone, or whether they should be regarded as forming part of the sublittoral fringe. The present writer prefers to include all the above-listed belt-formers in the midlittoral zone, on the basis of their vertical position with reference to tide-levels (cf. Dellow, 1950a). Despite their more cumbersome nature, the terms upper, mid- and lower midlittoral have crept into this account, in the absence of other convenient terms of reference. Possibly “littoral” would be preferable in this instance. As far as possible, therefore, each belt has been designated either by its dominant organism or by its prevailing characteristic, whether colour, or habitat.

4. Sub- (Infra-) littoral Fringe Whichever prefix is preferred (“sub-” is chosen here for the sake of its widespread usage), the sector of the sublittoral proper to which the term applies is without doubt a natural and clearly defined one. Perhaps the most physiognomic feature of the Gulf rocky shores between M.L.W.M. and E.L.W. S.(approx.) is the dominance of Carpophyllum spp., less often replaced by Cystophora, Sargassum, Ecklonia, and rarely Lessonia. Womersley and Edmonds (loc. cit.) state that the fringe does not exist in its own right on Kangaroo Island, since it is merely an upward extension of a more or less uniform, upper sublittoral. Nevertheless they admit that Cystophora intermedia dominates an exposed belt which continues downward for only a limited distance (2 or 3 feet) Until more information is assembled from the sublittoral proper it is considered by the writer undesirable todogmatise about any further subdivisions. It may be noted, however, that there is a definite restriction on downward colonisation of dense belts of Cystophora torulosa, Carpophyllum maschalocarpum and C. elongatum whenever these occur in the sublittoral fringe. C. plumosum is an exception, for it is known to grow in submerged “forests” up to 4 fathoms below E.L.W.S. at Little Barrier (Station 24). The validity of the sublittoral fringe concept may be affected by the degree of encroachment of large brown algae from the sublittoral proper. Information supplied in Table VIII, Part III,* Table VIII, Part III: Records of sublittoral brown algae in the Hauraki Gulf. indicates that none of the characteristic fringe species except Cystophora torulosa and possibly Carpophyllum elongatum (?) is confined to tide levels above E.L.W.S. This fact could be used to support Womersley and Edmonds' argument that there is no such zone as a sublittoral fringe. On the other hand the following facts seem to the present writer to support the view that the fringe has a valid entity and belongs, strictly speaking, to the littoral (in Stephenson's sense (1949, p. 200), i.e., from about E.H.W.S. to E.L.W.S.): (i) the presence of dominant brown algae, whatever their entire ecological range, in regular horizontal bands, made up of more or less uniformly dense aggregations of individuals; (ii) the frequent modification in growth form of the components, chiefly by their stunted length in comparison with continuously submerged thalli; (iii) the change in nature and effect of the governing environmental factors. Chapman and Trevarthen have drawn attention to the probable limiting effects of continuous emergence on upward extension of sublittoral species, and of continuous submergence on downward spread of littoral groups. Added to these is the mechanical and aerating action of breaking waves. 5. Sublittoral Zone Most authorities agree that the sublittoral embraces that part of the shore which is covered at all tides, being influenced only indirectly by tide and surface wave action. Its lower limit is not within the scope of this discussion. Ecklonia radiata, most typical in the Gulf waters, is replaced by Lessonia variegata on more rugged coasts; but growth of the massive laminarians occurs in isolated clumps rather than in clearly defined belts, except where Ecklonia holdfasts are attached to rocks in the sublittoral fringe.

With regard to the previous use of certain terrestrial ecological terms to cover marine groups of organisms (Chapman and others in this series), it is now thought more practicable to follow T. A. and Anne Stephenson in using the generalised and non-committal term “community”, more especially since the true status of marine biotic communities cannot be assessed with any accuracy upon brief visits to a great number of stations. The idea of an “association-complex”, introduced in New Zealand by Cranwell and Moore (1938, p. 382), is particularly suitable for the study of intertidal zonation; therefore it is proposed to modify the implications of the word “association” by substituting “community”, in the combination “community-complex”. Like the former term, this primarily embraces the vertical sequence of belts from supra- to sublittoral in any given locality. In conclusion, attention may be drawn to the difficulty of assessing the basic zonation of a district from one short period of observation. The word “basic” implies some degree of permanence. Very little is known concerning the length of time that the local marine communities and their dominants will continue to occupy their present habitats. It is possible that there should be some criterion for length of life of a plant or animal before it can be allotted the rank of a dominant in the basic zonal sequence. Biotic Communities With the prosecution of an increasing number of local and regional studies of the New Zealand littoral (Oliver, 1923, Cranwell and Moore, 1938, Chapman, 1950, Dellow, 1950, Carnahan, 1952), most authors have recognised and described certain communities which were encountered. Others—e.g., Knox (1953), discuss the ecology of individual species. With the exception of Oliver's community descriptions, all are for restricted areas. Apart from an unpublished account by Cooper of the salt marsh at Hobson Bay, Auckland, no attempt has yet been made to correlate the information amassed in the above literature. This is most easily accomplished by means of Tables (Tables VI, VII). As is so often the case, ecological studies in this country have been hampered through insufficient knowledge of the taxonomy of the species concerned; and this applies even to a number of dominants.* The following names used by Oliver (1923) and others have been changed as indicated in the present account:— Oliver (1923) Dellow Algae:      Stypocaulon paniculatum = Halopteris spicigera      Zonaria turnariana = Z. subarticulata      Glossophora harveyi = G. kunthii      Ecklonia richardsonia = E. radiata var. richardiana      Caulacanthus spinellus = Gelidium pusillum      Amphiroa corymbosa = Cheilosporum corymbosum Animals      Turbo smaragdus = Lunella smaragda      Ostrea cucullata = Saxostrea glomerata      Modiolus pulex = Volsella neozelanicus      Vermilia carinifera = Pomatoceros coeruleus      Hermella spinulosa = Sabellaria kaiparaensis Littoral ecologists are generally agreed in the belief that the ecological units of rocky coasts are climax in nature, in spite of their small, often minute, spatial

dimensions and their relatively brief duration in time. This gains expression in both the major subdivisions (formations or biomes) and in the smaller climax categories listed in Tables VI and VII. In following the schema of T. A. and Anne Stephenson (1949, p. 299) the present writer does not deny the probable validity of the formations noted previously (see Column 2 of Table VI). But for the same reason that “community” is used instead of “association”—i.e., that our basic knowledge of the true status of these divisions of the rocky shoreline is far from complete, it seems wiser at present to omit the term “formation” altogether, whilst relating each zone or subzone to its relevant section of the littoral. To avoid confusion over upper, mid- and lower midlittoral, the Stephensons' (1952, p. 27) practice of naming each belt or zone after its chief characteristic—e.g., oyster zone, muddy zone, is perhaps the most convenient one to follow. On the other hand one finds it hard to avoid using such terms as upper, mid- and lower midlittoral (cf. Trevarthen, 1953, Fig. 3), especially where there is no conspicuous delimiting organism. The adlittoral—i e., maritime, land vegetation on the most seaward continuous soil (Johnson and Skutch, 1928; Trevarthen, 1953) is beyond the scope of consideration of this survey. Table VII reflects the change in ecological concepts which has taken place over the past 30 years. All New Zealand writers in this field have adopted a biotic approach, the chief improvements lying in a more precise delimitation of each unit, especially in relation to tide levels and amount of emergence and submergence, as well as in the recognition of seral groups, where they exist (Cooper, unpub.; Carnahan, 1952). Oliver (1923) made the first genuine attempt to classify the confusing multiplicity of forms occurring between New Zealand tide marks, when the subject of littoral zonation was in its infancy. Regarding an “animal-and-plant formation” as “a biotic community with its principal ecological groups in definite combination and in definite relation to the habitat”, Oliver distinguishes between forma Table VI. Correlation of the Major Subdivisions of New Zealand Rocky Shores Oliver (1923) Chapman (1950) Trevarthen (1953) Dellow Dellow (1950) Carnahan (1952) Adlittoral zone Supralittoral zone Supralittoral zone Littorina formation Supralittoral fringe Supralittoral fringe Shelled animals formation Upper Midlittoral Barnacle formation Mid-Midlittoral Midlittoral zone Coriaceous coated animals formation Lower Midlittoral Small emerging algae formation Lower littoral mixed algae formation Sublittoral fringe Sublittoral fringe Large brown kelp formation Sublittoral brown kelp formation Sublittoral zone Sublittoral zone The scheme followed in the present work coincides with that proposed by T. A. and Anne Stephenson (1949, p. 299) except in the use of ‘sub’ for ‘infra’-littoral. (In the first two columns the relation of zones to tide levels is only approximate.)

tions on rock and those on sand and mud. Thus a community on the above definition is equivalent to a wider unit embracing several “associations”, the latter corresponding approximately with the communities described in the ensuing text. Although the information in his paper is presented in such general terms, he describes a number of “formations” and “associations” which are prominent in the Hauraki Gulf, particularly those in Auckland Harbour and at Takapuna. His lists of subordinate species remain of considerable value to the littoral ecologist, but there is a need with our increased knowledge in this field for relating of the communities more precisely to their habitat. This has been achieved to a certain extent by later writers, for restricted localities. Cranwell and Moore (1938, p. 380) take an association to be composed of species which “form an interdependent unit in equilibrium with the existing environment” the dominants having power to “exclude all invaders of similar life form and requirements”. These writers have contributed a sufficiently detailed account of the Poor Knights littoral communities to provide a basis of comparison with the present survey of the Hauraki Gulf. The concept of single dominance is still upheld; however, in the Nemastoma, Xiphophora, Durvillea, Carpophyllum elongatum and Lessonia associations. Like later writers (cf. Table VII), Cranwell and Moore have not been able to decide with certainty the status of certain groups which fall outside their definition of the littoral, in this case of lichens and Cyanophyceae; and so they have used the noncommital term “community”. Their employment of terms such as biocoenose, epibiose and hypobiose, used also by several European authors, has not been followed here. Chapman, Beveridge, Dellow and Carnahan have carried the process of classifying the groups further by defining them more accurately in terms commonly used in climax land ecological terminology, while Carnahan and Cooper give due recognition to the seral nature of Zostera and Avicennia, together with several algal “socies” densely clothing mangrove stems and pneumatophores, dominated by Caloglossa, Catenella, Rhizoclonium and sometmes also the barnacle Elminius modestus. The fact that the mangrove swamp is seral in nature is considered sufficiently valid grounds for treating the associated algal groups in a like manner. Owing to longer periods of observation on each area, the above-mentioned studies have shed more light on seasonal aspect communities. Following on this segregation of different types of community one could proceed almost indefinitely with the recognition of different units, whether one prefers to call them fasciations, sociations, clans, families, or similar terms; in fact the number of subdivisions made to date has appeared to depend at least partly on the length of time each writer spent in studying a particular locality, as well as on his or her chief interest. The fact remains that our knowledge of the majority of littoral communities comes from purely subjective observation; and until dominance is placed on a statistical basis we cannot be sure of the exact ecological status of a given assemblage. To avoid further multiple usage, therefore, the present writer feels it necessary to abandon the previous practice of attaching a narrowly defined term to a seemingly distinct littoral group of species. Obviously, some communities will be more restricted in time and space than others, and certain dominants will hold sway according to minor variations in the habitat. It is not to be expected that any one community will be found in

Table VII. Marine Communities of the Rocky Shore Described by New Zealand Workers Author Oliver (1923) Cranwell & Moore (1938) Chapman (1950) Beveridge & Chapman (1950) Dellow (1950) Carnahan (1952) Locality New Zealand Poor Knights Stanmore Bay Piha Nerrow Neck Rangitoto Associations Caulacanthus; Bostrychis Porphyra; Ulva Corallina-Hormosira Corallina; Xiphophora Carpophylaum-Lessonia Durvillea Helaraphe Cellana-Monodonta Cellans-Monodonta Cellans-Nerita E. Plicatus; C. columns Vermilia; Modiolus Ostrea; Mytilus Corella; Cynthis Chthamalus, Apophloea- Novastoa-encrusting coralline Xiphophora Carpophyllum elongatum Rhodophyceae Lessonia Melaraphe-Lichina. Chamaesipho-Volsella-(Apophloea) Vermilis-Saxostrea Hormosira-Corallina Carpophyllum-Ecklonia Lichina pygmaea-Melaraphe Chamaesipho Modiolus-C. columns Vermilia-Hermella Durvillea-Mytilus Mytilus-attached algae Cladhymenia-Schizymenia Vidalia-Melanthalia-Pterocladia lucida Calothrix-Melaraphe Enteromorpha-Gelidium-Volsella Chamesipho-Klminius-Saxostrea Hermella-Vermilia Corallina-Hormosira Encrusting coral line Carpophyllum-Ecklonia Melaraphe-Lichina Chamesipho-Apophloea Chamaesipho-Saxostrea Corallina-Hormosira Carpophyllum-Ecklonis Consociations Bostrychia arbuscula Gigartina alveata Pachymenia himantophora Gigartina marginifera Calothrix Melaraphe Enteromorpha Volsella C. columns E. modestus Saxostrea Hormosira Fasciations Klminius-Scytothamnus Caloglossa-Catenella Myxophyceae Klminius-Modiolus Mytilus canaliculus-Tunicate Communities Lichen Verrucaria & Cyanophycae (+ Melaraphe) Fresh-Water seepage Brackish water Mytilus-attached, algae Clans Caulerpa Aspect Societies Chthamalus-Porphyra Nemastoms oligarthra Splachnidium Scytosiphon lomentaria Colpomenia sinuosa Myriogloia lindauerii Ilea fascia Porphyra-Bangia Myriogloia Helminthocladia Splachnidium Enteromorpha bulboss-Monostroma Associes Salicornis-Stipa Consocies Avicennia Zostera

another ecologically similar locality exactly as it is described here. Nevertheless widening experience of the behaviour of intertidal biota shows the remarkable selectivity of a certain organism (or organisms) for a particular type of environment. The occurrence of Bostrychia arbuscula and B. mixta on southerly, moist and shaded rock faces near high water may be cited as an algal example; and the restriction of Tethya fissurata, the golf ball sponge, to caves and the undersides of overhangs is an instance of animal preference. The question arises whether there is any such concrete entity as a community on the rocky shore. It is true that we might grow accustomed in zonation studies to thinking of belts or zones of individuals rather than of communities as basic units. It is not proposed to discuss the community concept in detail here, but it should be mentioned that most New Zealand writers on intertidal ecology, and indeed, many from overseas (e.g., Feldmann, 1938; Gislén, 1943, 1944; Womersley, 1947, 1948) have regarded the grouping of plants and animals which they observed as being composed of communities, chiefly of associations. T. A. and Anne Stephenson (1949, p. 301) see no objection to calling a subzone of, say, the “infralittoral” fringe a community, although they have not adopted the system, generally speaking. They do point out, however, that our present knowledge of the status of such groups is by no means clear. For the purposes of this work the definition of Dice (1952, p. 15) appears to be a suitable one. He considers an ecologic community to be “an assemblage of ecologically related organisms composed of two or more species”. If only one species is present, as in several seasonal units on the seashore, the term “society” should be applied. The time factor in connection with the community status is one which needs further investigation. On a brief visit to the rocky coast one is confronted by a community complex which represents a seasonal cross section of a reticulation formed by the origin, growth, decline and regeneration of each unit. An analogy comes to mind from the complex vascular structure of a dictyostelic fern. A cross section at a particular level portrays only an incomplete impression of the structure of the whole, and yet is a considerable aid in understanding the fundamental anatomy of the stele. The concept of a community complex as a cross section of a reticulate system is infinitely more complex, nevertheless it is a necessary one before a complete picture of intertidal (and also land) biota can be obtained. In other words one should be familiar with the geological age of a particular shore, with the time during which ecological factors (both tidal and climatic in this case) have undergone no major change, and with the seasonal appearances and fluctuations in abundance of the constituent organisms. After consideration of all previous accounts of biotic communities in the littoral region of the Hauraki Gulf, the writer has attempted in the following list to note each unit in terms of its general occurrence, in preference to repeating the more detailed descriptions already published for the majority of communities from restricted localities. A generalised picture of dominance has been aimed at, rather than an exhaustive list of the many component species. No account has been taken of the biota beneath overhangs or below movable boulders. Information arising out of the Hauraki Gulf survey has been summarized from a more extensive account (Dellow, unpub.).* Ph.D. thesis, 1953.

I. Supralittoral Zone 1. Grey and yellow lichen community (cf. Plate 4, Figs. 1 and 2). Ramalina leiodea (f-d).† d = dominant; a = abundant; f = frequent; o = occasional; r = rare; l = local. Physcia sp. (f-d). Parmelia sp. (f-d). Xanthoria parietina (a-d). Cladina sp. (l). Mesembryanthemum australe (f). Vertical Range: From the lower limit of the adlittoral—i.e., soil vegetation, to the upper boundary of the supralittoral fringe. Xanthoria, however, often descends into the latter. Occurrence: (a) Hauraki Gulf Most conspicuous on firm or crumbling, weathered cliff faces above greywacke intertidal platforms, the grey band usually above the yellow—e.g., round the rocky shores of Waiheke, the Noises, Western Coromandel Peninsula and Great Barrier. Common also on loose boulders, as at Little Barrier. Absent on Waitemata Sandstone cliffs. (Stations 2, 15, 19, 20, 21, 24, 25, 30, 31). (b) New Zealand.* Localities given are those which have been published specifically, and those known personally to the writer. Probably widespread. 2. Metrosideros excelsa (Pohutukawa) community. Cockayne, 1928. Vertical Range: Throughout the supralittoral zone. Occurrence: (a) Hauraki Gulf A feature of nearly all cliffs, varying in density from a single tree to a dense covering. Notable on Rangitoto, growing among scoria down almost to E. H.W.S.; fringing the littoral of Waiheke, Western Coromandel Peninsula and Great Barrier, and partly to completely obscuring the naked cliffs of Little Barrier (Stations 14, 21, 24, 25; cf. Hamilton, 1937, Pl. XVII). (b) New Zealand On North Island cliffs, from Lat. 39 in the west, to north of East Cape (Cockayne, 1928). 3. Prasiola community. Prasiola stipitata (ld). P. crispa (r). Vertical Range: From 40 feet above E.H.W.S. down to the upper limit of the supralittoral fringe. Occurrence: Hauraki Gulf So far, P. stipitata is recorded only from Gannet Rock (Station 22), the extent of its moss-like growth probably correlated with the prevalence of gannet excreta. P. crispa was found in cracks in volcanic rock immediately above E.H.W.S. at Whitianga (Station 30).

II. Supralittoral Fringe 4. Lichina-Melaraphe community. Chapman, 1950, p. 64. Beveridge and Chapman, 1950, p. 190. Carnahan, 1952, p. 37. Vertical Range: From the upper fringe or, in wave-beaten situations, the upper limit of spray to M.H.W.N. Occurrence: (a) Hauraki Gulf Widespread in all sectors except the Waitemata Sandstone area of the East Coast mainland, where Myxophyceae mostly replace Lichina. Even where it dominates, Lichina tends to be isolated in discontinuous patches rather than to grow in a dense, black belt, although it is generally thick enough for such to be recognised from the sea in contrast with the yellow and grey bands above it (Stations 1, 2, 7–9, 11, 13–17, 19–21, 25, 27–30, 32). (b) New Zealand Widespread; Bay of Islands, Piha, Wellington, Banks Peninsula, Otago Peninsula. 5. Calothrix-Melaraphe community. Dellow, 1950, p. 363. Vertical Range: E.H.W.S. to M. H.W.N. Occurrence: Hauraki Gulf Predominant on Waitemata sandstone ledges as a leathery, blackish crust, caked with salt when dried out, extremely gelatinous and slippery when moist. Chiefly at Narrow Neck, where it replaces Lichina (Stations 3, 5, 9, 10). 6. Caloglossa-Catenella community. Carnahan, 1952, p. 37. Cooper (unpub.) p. 32. Vertical Range: As for Lichina-Melaraphe. Occurrence: (a) Hauraki Gulf In moist shaded crevices among scoria on Rangitoto, and also on mangrove pneumatophores. (b) New Zealand Bay of Islands, Piha (with local variations—Beveridge and Chapman, 1950, p. 190). 7. Bostrychia community. Oliver, 1923, p. 527. Beveridge and Chapman, 1950, p. 191. Vertical Range: From M.H.W.S. to M.H.W.N. Occurrence: (a) Hauraki Gulf Common as a dark reddish black, finely tufted belt on moist, shaded rocks above Chamaesipho, especially near cave mouths. B. arbuscula may be intermingled with B. mixta or dominate on its own (Stations 2, 5, 10, 15, 17, 19, 20, 21, 23, 26, 28, 33).

(b) New Zealand Widespread in similar habitats in both islands, the southern form of B. arbuscula larger and more robust than the northern. 8. Myxophyceae community. Carnahan, 1952, p. 37. Trevarthen, 1953, p. 10. Vertical Range: As for Lichina-Melaraphe. Occurrence: (a) Hauraki Gulf On the more sheltered shores of Rangitoto, in conjunction with a certain amount of sedimentation. Frequently encountered at the base of sandstone cliffs, where it may merge with the fresh water seepage community, as at northern Orewa (Station 10). More pronounced in shaded, southerly situations. (b) New Zealand Probably widespread. 9. Freshwater seepage community. Chapman, 1950, p. 67. Beveridge and Chapman, 1950, p. 194. Vertical Range: Throughout the supralittoral fringe. Occurrence: Hauraki Gulf Characteristic on sandstone ledges worn smooth by ramwater seeping down in wet weather from the land vegetation above. Generally a short-lived, winter and spring community, its vigour determined by the amount of rainfall in a particular season. Scytosiphon lomentaria is a notable winter aspect which may be locally dominant together with Enteromorpha compressa f. subsimplex. At high shore levels the tubes of Scytosiphon are typically stunted—not more than 6–8 cm. long, and lacking the sausage-shaped constrictions of low neap-tidal thalli (Stations 6, 7, 9, 10). III. Midlittoral Zone 10. Chamaesipho community (cf. Plate 4, Figs. 1 and 2). Oliver, 1923, p. 535. Cranwell & Moore, 1938, p. 384. Chapman, 1950, p. 65. Beveridge and Chapman, 1950, p. 191. Dellow, 1950, p. 366. Carnahan, 1952, p. 37. Trevarthen, 1953, p. 9. cf. Knox, 1953, p. 198. Vertical Range: From M.H.W.S. to M.L.W.N. Occurrence: (a) Hauraki Gulf A barnacle zone is ubiquitous in situations from moderate shelter to extreme exposure in the upper midlittoral, except on movable boulder substrates, where colonisation appears to depend on the degree of stability of the boulders and the intensity with which they are insolated. Subordinate species are listed in the individual accounts of the writers already mentioned (cf. Table II). Suffice it to say here that a number of communities have been recognised within this zone,

according to the prevailing dominants in a localised area. This present survey amply illustrates the replacement of C. columna by E. modestus in more brackish, silted up areas, and by C. brunnea with a change to oceanic conditions. All stages of gradation may be observed between these extremes. Where C. brunnea and C. columna occur together, the former occupies a belt above the latter (Stations 9, 15, 18–22, 28–30, 32–34). Within the wide vertical range of dominance of C. columna its place may be taken by any one of the co-dominants. According to each writer's preference these may be regarded as belonging either to the barnacle community or as dominants of a number of separate ecological groups. (b) New Zealand Widespread; Bay of Islands, Poor Knights, Piha, Tauranga, Wellington, Banks Peninsula, Otago. 11. Apophloea community. Apophloea Elminius Assn. (Cranwell & Moore, 1938, p. 386.) Carnahan, 1952, p. 37. Vertical Range: From M.H.W.N. to M.S.L. Occurrence: (a) Hauraki Gulf Forming dull red, leathery, circular patches on otherwise bare rock, occasionally giving rise to branched, finger-like projections. Notable on the basalt scoria at Rangitoto, though also common on firm, slab-like greywacke and on the smooth boulders of Little Barrier. Scarce or absent on Waitemata Sandstone. Where it occurs in sufficient density it can be termed the “red belt”. Apophloea is eliminated from community complexes subject to extreme wave exposure (Stations 2, 9, 11, 14, 15, 18, 20, 28, 30–31). (b) New Zealand Bay of Islands, Poor Knights (C. columna replaced by Elminius plicatus—Cranwell & Moore, loc. cit.) 12. Enteromorpha procera f. minuta community. Dellow, 1950, p. 365. Vertical Range: From M.H.W.M. to M.S.L. Occurrence: Hauraki Gulf Chiefly on sunny ledges of Waitemata sandstone, but also forming a bright green sward from autumn to spring on flat basalt rocks between Takapuna and Milford and elsewhere. Common above barnacles on wharf piles and embankments in sheltered harbours. On Little Barrier shores it is replaced ecologically by E. nana, though this species dominates mainly below M.S.L. on the boulders, and ascends above that level only on an iron boat ramp. Despite its interrupted horizontal distribution and the seasonal fluctuations in abundance, the Enteromorpha sward is an important feature of the upper midlittoral inside the Gulf; in fact it is quite reasonable to regard it as a distinct subzone of the barnacle zone, most conveniently termed the “green belt”. E. procera f. minuta may dominate wide stretches of flat or gently inclined rock on its own or it may codominate with Gelidium pusillum, Volsella neozelanicus and, in winter and spring, with brown trails of Scytosiphon or Pylaiella (Stations 3–5, 8, 20, 23–25, 28–30).

13. Nerita community. Cellana-Nerita Assn. (Oliver, 1923, p. 537). Vertical Range: M.H.W.M. to M.S.L. (approx.). Occurrence: (a) Hauraki Gulf Prominent not only on boulder beaches of Little Barrier and Coromandel Peninsula, but also on Waitemata Sandstone ledges, notably on Whangaparaoa Peninsula. Cellana mingles with Nerita near the lower limit of the latter rather than right through its vertical range. Like Melaraphe, Nerita roams freely over rocks and boulders still cooled and wet by the receding tide, but retreats to crevices and overhangs when the moisture dries (Stations 4, 9, 13, 22, 28). New Zealand Bay of Islands, Poor Knights. 14. Volsella (Modiolus) community. Oliver, 1923, p. 532. Dellow, 1950, p. 366, Fig. 8. Modiolus—C. columna assn. (Beveridge, and Chapman, 1950, p. 191). cf. Knox, 1953, p. 204. Vertical Range: From M.H.W.N. to M.L.W.N. Occurrence: Hauraki Gulf Shining black clusters congregated in situations of moderate shelter to moderate wave exposure on both sandstone and basalt vertical faces. C. columna and E. plicatus are frequent associates. Volsella generally drops out of the mosaic of communities on severely wave-exposed headlands. (Stations 3, 5, 7, 9–10, 12, 14, 20, 26, 32.) New Zealand Bay of Islands, Piha, Banks Peninsula. 15. Saxostrea community. Ostrea assn. (Oliver, 1923, p. 531, Plate 43, Fig. 1; Plate 46, Fig. 2.) Chapman, 1950, p. 66. Dellow, 1950, p. 367, Fig. 9. Chamaesipho-Saxostrea assn. (Carnahan, 1952, p. 37, Figs, 2, 3). Vertical Range: From M.S.L. to M.L.W.N. Occurrence: (a) Hauraki Gulf Characteristic of wave-protected waters in nearly all parts of the Gulf, forming a dense to open belt of crinkly, white shells edged with purple; on sandstone, basalt and greywacke. Tolerant of a considerable amount of turbidity and pollution, as at St. Leonard's Point and on breakwaters near city wharves. Replaced by C. columna or by Lithothamnia on open coasts (Stations 2, 5–9, 11, 13–21, 28, 32.) (b) New Zealand Northern portion of the North Island, Chathams (Powell, 1937, p. 19). 16. Elminius-Scytothamnus community. Dellow, 1950, p. 366. Cf. Knox, 1953, p. 199. Vertical Range: From M. S. L. to M.L.W.N.

Both Elminius plicatus and E. modestus may become established above M.S.L. in absence of competition from other organisms; E. plicatus occurs higher on a more open shore—e.g., Gannet Rock. E. modestus flourishes where turbidity or pollution discourages the settlement of C. columna. Occurrence: (a) Hauraki Gulf On sandstone, basalt and greywacke in situations of moderate shelter to moderate wave exposure. E. plicatus, E. modestus and Saxostrea occur together at Narrow Neck, but more often the barnacles dominate in separate communities. Scytothamnus may do likewise, as at Wha Wha north of Mercury Bay (p. 165). Thick yellowish-white encrustations of E. plicatus fringing tilted sandstone ledges are a feature of the East Coast mainland. Gannet Rock displays a scattered but wider ranging population of E. plicatus, which is the only barnacle present. (Stations 1, 4–7, 9, 10, 13–16, 21–23, 26–29, 31–33.) (b) New Zealand Bay of Islands, Poor Knights (E. plicatus only), Banks Peninsula. 17. Pholadidea (rock-boring) community. (Plate 1, Fig. 2) Anchomasa similis (d). Pholadidea spathulata (d). P. tridens (a). Lithophaga truncata (a). Vertical Range: From M.S.L. to M.L.W.S. Occurrence: Hauraki Gulf Ubiquitous in soft mudstone strata of the Waitemata Sandstone area. The rock borers may protrude one or two centimetres from their holes, but more often the surface of the grey mudstone is blank save for innumerable small holes. 18. Sabellaria-Pomatoceros community (cf. Plate 1, Fig. 1) = Hermella-Vermilia assn. Cf. Oliver, 1923, p. 533, Plate 48, Fig. 2. Beveridge and Chapman, 1950, p. 191. Dellow, 1950, p. 367. Cf. Knox, 1953, p. 205. Vertical Range: From just below M.S.L. to M.L.W.N. Occurrence: (a) Hauraki Gulf On coasts of moderate shelter, especially in close proximity to sand or sandy mud (Stations 1, 5, 9, 10). The present survey has shown that Pomatoceros is more tolerant to variation in habitat than is the sandtube worm Sabellaria. Hence it is often found as a belt on its own in quite open, wave-battered situations (Cf. Stations 28, 30, 34). (b) New Zealand Piha, Banks Peninsula, Otago Harbour. 19. Gigartina alveata community. Beveridge and Chapman, 1950, p. 192. Vertical Range: From M. S. L. to about M.L.W.N. (a) Hauraki Gulf Poorly represented in a few open coast localities by stunted thalli growing among barnacles or acting as sand traps on bare rock. Paucity of growth in

Fig. 1.—Station 4. Bastion Reet engulfed by a dense growth of Pomatoceros coeruleus. Fig. 2.—Station 5. St. Leonards Point: Rock-boring community of Pholadidea spp. Anchomasa similis and Lathophaga truncata burrowing into soft Wartemata Sandstone

marked contrast to its vigorous occurrence on the west coast at Piha. (Stations 20, 30, 34.) (b) New Zealand Bay of Islands, Poor Knights, Piha. 20. Ralfsia-Hapalospongidion community. Cf. Lindauer, 1949, p. 348. Ralfsia verrucosa (d). Hapalospongidion saxigenum (ld). basal Corallina officinalis (f). Cellana spp. (f). Nerita melanotragus (f). Vertical Range: From about one foot below M.S.L. to upper limit of algal turf. Occurrence: (a) Hauraki Gulf Of the two dominants Ralfsia is by far the commoner, and is to be found in varying density as light reddish-brown brittle crusts about the upper limit of the coralline turf. Only at Little Barrier were the two crusts observed to intermix. Indeed it is hard to distinguish them, except by the more yellow-brown colour of Hapalospongidion which is pulpy when scraped off the rock. Both species erode first in the centre when dying. (Stations 1, 5, 8–10, 12, 14, 15, 17, 19, 22, 24, 25, 28, 29–31.) (b) New Zealand Bay of Islands, Pihama (Taranaki), Wellington, Kaikoura, Stewart Island. 21. Corallina-Hormosira community. Oliver, 1923, p. 524, Plate 44, Fig. 1. Chapman, 1950, p. 67. Dellow, 1950, p. 368, Fig. 11. Carnahan, 1952, p. 38. Cf. Knox, 1953, p. 197. Vertical Range: From E. (H.) L. W. N. to M. L. W. S. Occurrence: (a) Hauraki Gulf Widespread on flat or gently inclined reefs and rocks in places of moderate shleter to moderate wave exposure. Hormosira is a denizen of even more protected, mud-silted habitats than Corollina, though the latter can stand a considerable coverage of mud. The variety in composition of subordinate species as well as in relative abundance of the dominants has been described in the works of the above-mentioned writers. The coralline turf is short and scrubby with a frequently bleached appearance, contrasting with the deeper pink, more feathery growths in tide pools. Hormosira, too, exists in a number of varying ecological forms (Lindauer, 1947, p. 563; Moore, 1950), the so-called var. sieberi consisting of small, slender thalli, mostly attached to Corallina; and a gradation of communities to those where receptacles are up to 3 cm in diameter, as on mudflats among the pneumatophores of Avicennia (Stations 1–20, 27–28, 30, 32, 34). (b) New Zealand Sheltered localities; Kermadecs, North Cape to Stewart Island.

22. Codium adhaerens community. (Cf. Knox, 1953, p. 197.) C. adhaerens (d). Elminius modestus (Id). Chamaesipho columna (Id). Ceramium apiculatum (a). Elysia mooria (f). Laurencia thyrsifera (f). Colpomenia sinuosa (f). Hormosira banksii var. sieberi (f). Cladophora crinalis (o). Ectocarpus indicus (o). Vertical Range: From about E.(H.) L.W.N. to M.L.W.S. Subject to considerable shade and wave elevation (Dellow, 1950, Fig. 10; 1952, Fig. 1). Occurrence: (a) Hauraki Gulf Occurring on all types of rock in spring, summer and autumn, especially on seaward fringes of sandstone ledges as a spongiose, corrugated, velvet-green fringe; above the coralline turf in a well-defined belt on rocks facing south in the lower barnacle zone. (Stations 3–5, 8–10, 13–15, 17, 19–22, 27, 30, 32, 34.) (b) New Zealand North Cape to Banks Peninsula. 23. Mixed algal turf community. (Plate 2, Fig. 2) Enteromorpha nana (d). Ulva lactuca (d). Caulacanthus spinellus (ld). Gelidium caulacantheum (ld). Gigartina laingii (a). Polysiphonia sp. (a). Leathesia difformis (f) Ralfsia verrucosa (f). Ilea fascia (o). Vertical Range: From M.L.W.N. to M.L.W.S. Occurrence: Hauraki Gulf Replacing Corallina and Hormosira ecologically at Little Barrier on the larger boulders of the lower midlittoral. The actual upper limit of the turf does not follow a horizontal line, but is regulated by the expanse of lithothamnia or Ralfsia above it, and is determined to a certain extent by the swash of waves between the boulders (Fig. 11). Also on oceanic rock platforms at similar levels, e.g., the north face of Saddle Island and on shelving slopes at Needles Point, immediately above Durvillea (Stations 24, 25, 32(c), 33). (b) New Zealand Moko Hinau. 24. Xiphophora community. Oliver, 1923, p. 523. Cranwell and Moore, 1938, p. 391. Vertical Range: From E. (H.) L.W.N. to M.L.W.M. (or upper sublittoral fringe).

Fig. 1.—Long Bay: East Coast Mainland Ecklonia radiata vai richardiana and Carpophyllum maschalocarpum with laminae cast over exposed, sublittoral fringe rocks in the direction of on shore waves. Fig. 2.—Station 25. Pohutukawa Flat. Little Barrier Island: Irregular zonation patterns on boulders in the lithothamnia and algal turf belts Nemastoma oligarthra appears as black dots at the top left. Cellana sp. and young Codium adhaerens var contolutum are above the mixed algal truf.

Occurrence: (a) Hauraki Gulf Characteristic as a light brown, Fucus-like band fringing the lower barnacle zone on nearly all rocky coasts subject to moderate or extreme (but not maximum) wave exposure. Wave exposure is eliminated under conditions of greatest turbulence by Carpophyllum elongatum and Durvillea. Xiphophora will grow on a sandstone substrate, but is scarce on the east coast mainland since in general the shores here are shallow, sheltered and often partly silted. Plants at the upper limit of its range are mostly stunted in size compared with those at the lower fringe. According to Cranwell and Moore (loc. cit.) Pachymenia himantophora replaces Xiphophora on the west coast of Auckland. Within the Gulf its level is sometimes occupied by Cystophora torulosa, as at Cape Rodney (Station 12). Oliver's statement (loc. cit.) that Xiphophora is confined to “small level stretches of rock about low tide mark” does not apply to most habitats inside the Hauraki Gulf; in fact it is characteristic of seaward rock faces with a slope of at least 30–45 degrees. (Stations 8, 11, 13, 14, 10–25, 28, 30, 32, 34.) (b) New Zealand North Cape to Poverty Bay (East Coast), Hokianga Heads (West Coast). 25. Mytilus canaliculus-attached algae community. Mytilus assn. (Oliver, 1923; p. 531). Beveridge and Chapman, 1950, p. 193. Dellow, 1950, p. 370. Cf. Knox, 1953, p. 203. Vertical Range: From M.L.W.N. to below E.L.W.S. Occurrence: (a) Hauraki Gulf Locally dominant on sandstone and greywacke shores in places from moderate shelter to extreme wave exposure. In the Gulf it may compete with and completely oust Corallina; therefore despite its extended lower boundary well into the sublittoral it is best regarded as a lower littoral assemblage. (Stations 2, 5, 14, 15, 21, 22, 30.) (b) New Zealand Piha, Taylor's Mistake (Banks Peninsula). 26. Lithothamnia community (Plate 2, Fig. 2) Novastoa-encrusting coralline assn. Cranwell and Moore, 1938, p. 388. Encrusting coralline assn. (Dellow, 1950, p. 370). Lithothamnion sp. (d). Lithophyllum sp. (d). Melobesia sp. (d). Basal Corallina officinalis (d). Peyssonelia rubra (f). P. harveyana (l). Hildenbrandtia crouanii (f). Vertical Range: From below M.S.L. to below E.L.W.S. Occurrence: (a) Hauraki Gulf Conspicuous as a pink, crustaceous band in many parts of the lower midlittoral and also in the sublittoral fringe. The community is segregated ecologically into two distinct sections:

(i) that dominated by thin crusts of Melobesia and basal Corallina, and (ii) that in which coarser knobbly crusts of Lithothamnion and Lithophyllum predominate. Group (i) occurs in more sheltered localities, both above and below the erect coralline turf. Group (ii) on the other hand is typical of oceanic waters, but there may be a mingling of both thin and thick crusts in the one community. (Stations 2, 4, 5, 10–12, 15, 21, 23–25, 28–30, 32, 34.) (b) New Zealand Bay of Islands, Poor Knights, Moko Hinau. IV. Sublittoral Fringe 27. Carpophyllum-Ecklonia community (Plate 2, Fig. 1) Carpophyllum assn. (Oliver, 1923, p. 521). Chapman, 1950, p. 67. Dellow, 1950, p. 370. Carnahan, 1952, p. 39. Cf. Knox, 1953, p. 196. Vertical Range: From M.L.W.S. to below E.L.W.S. Occurrence: (a) Hauraki Gulf The most important community of the sublittoral fringe inside the Gulf, appearing at low spring tide as a dark brown belt one or two feet in vertical width, separating the intertidal region from the sublittoral proper; stretching almost continuously round reefs and headlands from shallow, fairly turbid localities to those of moderate to extreme wave exposure. Ecklonia figures locally as the sole dominant reaching its maximum development in the sublittoral zone, or where its massive laminae can trail in deep, turbulent water from its holdfast attached in the fringe. C. plumosum replaces C. maschalocarpum in very sheltered waters, but also in the current-swept fringe and clear sublittoral zone about Little Barrier. (Stations 2, 4–25, 27, 28, 30–32.) (b) New Zealand North Cape to Stewart Island. (Ecklonia is more abundant on the sheltered east coast of the North Island.) 28. Carpophyllum elongatum community. (Plate 3, Fig. 2) Cranwell and Moore, 1938, p. 394. Vertical Range: From about M.L.W.N. to E.L.W.S. Subject to considerable surge elevation. Occurrence: (a) Hauraki Gulf Confined to very exposed coasts, not strictly inside the Gulf, and giving way to C. maschalocarpum where there is any degree of shelter. Occasionally associated with Lessonia (Station 29, Plate 3, Fig. 1) and Durvillea (Station 33). (Stations 29, 32c, 33, 34.) (b) New Zealand Bay of Islands, Bream Head, Poor Knights, Moko Hinau, eastern Coromandel Peninsula, Mayor Island. 29. Rhodophycean community. Cranwell and Moore, 1938, p. 396. Vidalia-Melanthalia-Pterocladia lucida assn. (Beveridge and Chapman, 1950, p. 194).

Fig. 1.—Station 29. Sugar Loat Rocks: Lessonia tarregata laminae exposed at E.L.W.S. Xiphophora chondrophylla vat minus is in the foreground. Fig. 2.—Station 33. Needles Point, N. E. Great Barriel Island: Zonation in a north face under conditions of maximum wave exposure for the Haraki Gulf region. Sparse growth of Durrillea above Carpophyllum clongatum.

Gigartina cranwellae (d). Pterocladia lucida (d). Pachymenia himantophora (ld). Melanthalia abscissa (a). Gymnogongrus nodiferus (la). Sarcodia montagneana (f). Acodes nitidissima (f). Rhodymenia leptophylla (f). Pterocladia capillacea (f). Vidalia colensoi (l). Vertical Range: From M.L.W.M. to below E.L.W.S. Occurrence: (a) Hauraki Gulf Represented as a “permanent” community only by Pterocladia lucida, P. capillacea, Melanthalia abscissa and Rhodymenia leptophylla, all of which occur more usually as subordinates in the Carpophyllum-Ecklonia fringe. Conspicuous on the east coast in exposed situations (Stations 30, 34), the specific composition varying from station to station. (b) New Zealand Bay of Islands, Poor Knights, Piha. Seasonal Aspect Communities and Societies A. Winter-Spring 1. Enteromorpha-Monostroma community. Carnahan, 1952, p. 38. Vertical Range: Towards upper limit of barnacles. Occurrence: Hauraki Gulf In sheltered positions, Rangitoto; also present in summer. 2. Scytosiphon lomentaria society. Beveridge and Chapman, 1950, p. 194. Vertical Range: About M.H W.N. and M.L.W.N. Occurrence: (a) Hauraki Gulf Scytosiphon has been observed in two separate communities, each with a different growth form, one near high and one near low water. The high water group (cf. fresh water seepage community, p. —) comprises short, thin tubes without noticeable constrictions, and is not infrequently met with on the east coast mainland (Stations 5, 8, also Milford Reef). The low neap tidal group of constricted thalli up to 30 or more cm. long has been observed at only one of the stations examined, namely Raukura Point (Station 2) in the Firth of Thames. L. M. Cranwell (herb. sheet, Auck. Museum) records this form from Point Chevalier Reef, Upper Waitemata Harbour, in August, 1931. (b) New Zealand Piha. (Possibly the small plants noted by Beveridge and Chapman at low neap tide are more like those growing higher up on east coast rocks.)

3. Ilea fascia community. Beveridge and Chapman, 1950, p. 194. Vertical Range: About M.L.W.N. Occurrence: (a) Hauraki Gulf Not common in sufficient numbers to form a separate community, except locally on Little Barrier boulders. Generally a subordinate among coralline or mixed algal turf (Stations 2, 5, 24, 25, 29). (b) New Zealand Piha, at similar level. 4. Porphyra umbilicalis ? -Bangia vermicularis community. Dellow, 1950, p. 371. Vertical Range: From M.H.W.S. to M.H.W.N. Occurrence: Hauraki Gulf On flat or gently inclined sandstone ledges; Bangia may form a small red-brown band on its own or with Enteromorpha procera f. minuta on smooth walls of steep slopes (Station 5). Represented by Enteromorpha nana and Bangia fusco-purpurea on Shag Cliffs, Little Barrier (Station 24). 5. Porphyra columbina society. Vertical Range: From about M.H W.N. to M.S.L. Occurrence: (a) Hauraki Gulf Poorly represented in a few exposed coast localities by stunted, rosette-like thalli (Stations 23, 25, 29, 34). (b) New Zealand Widespread on wave-exposed coasts; e.g., Piha, Anawhata, Te Henga, Wellington. B. Spring-Summer 6. Tinocladia novae-zelandiae community. Vertical Range: From about M. L.W.N. to M.L.W.S. Occurrence: Hauraki Gulf Sporadic in appearance; so far observed as a separate community only once at Clifton Beach, north of Narrow Neck (the type locality for this species). 7. Myriogloia lindauerii society. Beveridge and Chapman, 1950, p. 194. Dellow, 1950, p. 371. Vertical Range: From E.(H.)L.W.N. to upper limit of coralline turf or of sand. Occurrence: (a) Hauraki Gulf Locally dominant as a belt of dark-brown, worm-like thalli attached to margins of flattened rock platforms on the East Coast mainland and on Waiheke (Stations 2,5,20). (b) New Zealand Piha.

8. Colpomenia sinuosa community. Beveridge and Chapman, 1950, p. 194. Cf. Chapman, 1950, p. 67. Vertical Range: As for Corallina-Hormosira community. Occurrence: (a) Hauraki Gulf Often together with Lcathesia difformis, or by itself completely or partially obscuring Corallina with its inflated globose, pale yellow-brown sacs. Occurs in other seasons as well, but chiefly winter and spring. (Stations 4, 5, 9, 10, 12–13, 20, 25, 27.) (b) New Zealand Widely distributed. 9. Nemastoma oligarthra community. (Plate 2, Fig. 2) Cranwell and Moore, 1938, p. 390. Beveridge and Chapman, 1950, p. 193. Vertical Range: From about M.S.L. to upper limit of algal turf. Occurrence: (a) Hauraki Gulf Decidedly an exposed coast assemblage, not seen in the inner Gulf. Appearing as tiny rosettes of pear-shaped bladders dotting bare or barnacle-coated rocks above a mixed algal turf; showing a marked distributional response to upward surge, especially on Little Barrier shores. (Stations 18, 24, 25, 29.) (b) New Zealand Bay of Islands, Tauranga, Whangarei Heads, Poor Knights, Harriet Kings (East Coromandel Peninsula), Piha. 10. Splachnidium rugosum community. Beveridge and Chapman, 1950, p. 194. Dellow, 1950, p. 371. Vertical Range: From about M.S.L. to M.L.W.M. Occurrence: (a) Hauraki Gulf Appearing as a series of finger-like, corrugated, extremely gelatinous branches from a basal disc; hanging downwards from rock faces in groups from about two to a dozen thalli; frequently admixed with barnacles, C. columna, E. modestus and E. plicatus (Stations 2, 4, 5, 14, 17, 27, 29.) (b) New Zealand Widespread on both east and west coasts; e.g., Piha, Wellington, Stewart Island, Chathams. 11. Liagora-Helminthocladia community. Cf. Dellow, 1950, p. 371. Vertical Range : From M.L W.N. to M.L.W.S. Occurrence: Hauraki Gulf On flat rocks semi-covered with sand, East Coast mainland. Liagora harveyana and Helminthocladia austrahs have been observed co-dominating in one community (Red Beach, East Coast Mainland), although both are capable of existing alone—e.g., Helminthocladia at Clifton Beach, Liagora at Stanmore Bay. (Stations 5, 9, 10, 12.)

Part III.—Discussion and Conclusions. Discussion In this final section an attempt will be made to assess the prominent zonation features of the area as a whole. The biological and ecological response to a coastline such as that of the Hauraki Gulf, which is so indented, stream-dissected and complicated by the presence of a great many islands, is as varied as the shoreline itself. The same state of affairs has been observed further north at the Bay of Islands, an area providing a closely similar set of environmental conditions (Trevarthen, unpub.). Despite the danger of picking upon a single factor and allotting it too much prominence in trying to elucidate the causes of distributional changes, it is felt that wave-exposure may be taken, in the present incomplete state of our knowledge of tidal and climatic factors, as a convenient standard on which to classify the different types of rocky coastline. At the same time it must be considered in conjunction with other local factors (especially that of substrate), each of which will play a role in organising the finer details of a generalised zonation pattern; for instance the effects of increased shadow, protection from surf or surge and deposition of fine silt encouraging local dominance of Microdictyon mutabile in the Corallina belt (Stations 11, 32). Consideration will now be given to (A) horizontal zonation in the Gulf as a whole; (B) vertical zonation of selected community-complexes, each representative of a distinctive type of shore, and finally (C) a comparison of Hauraki Gulf zonation patterns with those recorded from other rocky coasts both in and beyond New Zealand. A. Horizontal Zonation. 1. Supralittoral Zone According to the locality, the supralittoral zone may be completely devoid of colonists, or it may be quite obscured by a continuous cover. On most Waitemata Sandstone cliffs the zone is bare (contrast however, Fig. 7) owing chiefly to the rapid erosion of the soft, crumbly strata and hence to the initial difficulty for any plants of securing a firm attachment. Added to this the generally porous nature of the cliffs does not aid in moisture conservation, except in places where there may be a seepage or trickle of fresh water from above. At several stations, the most striking being those on Little Barrier, naked cliffs are partially or entirely clothed by a canopy of Metrosideros excelsa, which thrives within reach of salt spray. Where its branches overarch upper midlittoral rocks, as at Station 32 (Port Fitzroy) shading effects are reflected in local variations superimposed upon the general zonation pattern. Phormidium and Bostrychia may find refuge in depressions on its shaded branches. Other angiosperms frequently encountered are Mesembryanthemum australe. Coprosma repens, Salicornia australis and Stipa teretifolia (Cf. Carnahan, 1952, p. 39). The most striking feature of the supralittoral in most other districts is the conspicuous cover of grey, and sometimes also yellow, lichens. The grey lichens (Ramalina, Physcia, Parmelia spp.) range upwards from a lower limit of about 2 to 50 feet above E.H.W.S. The density of cover varies according to degree of cohesion of the cliff surface (Cf. Fischer-Piette, 1936, p. 219). Xanthoria parietina generally occupies the band below, which may be included in the supralittoral fringe. This assemblage is a distinguishing mark in many places

inside the Gulf, in particular about the shores of Waiheke and smaller islands (e.g., Shag Rock, Plate 4, Fig. 1), and on bare cliff faces on west Coromandel Peninsula. But the grey lichen community is by no means restricted to relatively homogeneous, unbroken surfaces. At Whangaparapara (Station 31) and Little Barrier for instance, where the surface is made up of slab-like or rounded pebbles and boulders, foliose Physcia and Parmelia and tufted Ramalina abound. However, cohesion of the surface is still an important factor at these stations, for although the actual surface layer is irregular and dissected, the boulder faces are weathered to a smooth, firm, closely-compacted consistency. The occurrence of littorinids (Melaraphe spp.) in the supralittoral zone is confined to stations with a wave exposure index of McW2–4D2, Ta2 (Cf. Stations 28, 33); in other words, an exposed coast, fairly deep-water locality. Similar reports come from Piha (Beveridge and Chapman, 1950, p. 190). But in the majority of places where Melaraphe abounds in the Hauraki Gulf it seldom ventures above the upper extremity of the supralittoral fringe. Outliers from the fringe may include Verrucaria, Hildenbrandtia and Lichina. Figure 9 illustrates what a small percentage of the space available is actually occupied by these forms, which, at 5 or 6 feet above normal tide levels, are driven into sheltering cracks and crannies, and their presence is discovered only by an intensive search. While the supralittoral zone as a whole is of secondary consideration in the present survey, the prominence of the grey and yellow lichen belts in moderately sheltered parts of the Gulf is without doubt one of its physiognomic features. The uppermost limit of the belt does not concern us here, but is frequently regulated by the undulating, lower limit of soil (adlittoral) vegetation. The lowest limit is bounded by a sudden increase in black tufts of Lichina, where it is present, or by a naked expanse of rock if it is sparse or absent. Local development of Prasiola stipitata (Station 22) in a fairly exposed habitat associated with gannet droppings may be compared with Womersley's (1948, p. 149) report of a similar community on the site of well-worn penguin tracks at Pennington Bay, Kangaroo Island. 2. Supralittoral Fringe. The widespread occurrence of littorinids at these highest levels on tide-washed, rocky coasts has been affirmed for many parts of the world. As far as observations have been made to date the same applies in New Zealand (Oliver, 1923; Cranwell and Moore, 1938; Beveridge and Chapman, 1950; Dellow, 1950; Carnahan, 1952; Knox, 1953). Whereas Littorina species prevail on South African and European coasts, Melaraphe species replace them in Australasia (cf. also Nodilittorina, physiognomic in New South Wales—Dakin et al., 1948, p. 201). Stephenson (1949, pp. 296–7) stresses the need for further knowledge concerning the absence of ecologically important species from a niche for which they would appear to be well suited. While the list of species in Appendix I of this survey does not pretend to be an exhaustive one, and no doubt many more records could be added by other workers, it does show up the areas of concentration or comparative scarcity of many dominants from one or other type of station. The absence of grey and yellow lichens from the sandstone area has already been referred to. Lichina pygmaea is listed as a dominant at several stations, and yet it occurs in localised patches rather than as a continuous cover. Moreover, in these latitudes the blackish colour is contributed to by crusts of dark green

Verrucaria spp. and dull red-black Hildenbrandtia on firm rock, with blue-green algae becoming more conspicuous on sandstone (cf. Calothrix at Narrow Neck). On a vertical rock or cliff face the black band is seldom more than a foot wide— indeed it may be narrower. The limits are harder to establish on a flat reef or dissected platform. In such cases the width of the Lichnia belt is governed by the degree of elevation of the particular reef, which may be high enough in only isolated places. Like its grey and yellow relatives, Lichina is most conspicuous on cliffs of greywacke or conglomerate, although it has managed to gain an insecure foothold in a few sandstone localities—e.g., Whangaparaoa Peninsula. There is a notable absence of the black belt from Gannet Rock. It could be that the manganese in the rock affects this species adversely—or else the smooth surface has precluded its establishment. 3. Midlittoral Zone For the purposes of this study the midlittoral is regarded as covering the areas basically occupied by the barnacle and mixed algal zones. Within these zones the great diversity of plant and animal populations has already been indicated. Most common in all situations except those of extreme shelter and extreme wave exposure is the tiny white barnacle Chamnaesipho columna, ranging throughout the vertical extent of the midlittoral, but not everywhere as a dominant. Wherever there are estuarine conditions, plus a certain amount of turbidity— even pollution—in the seawater, C. columna can be expected to mingle with or give way to Elminius modestus, another tiny, stellate barnacle reproducing itself throughout the year in clustered thousands. E. modestus, too, is physiognomic on wharf piles above M. S. L. Both species are capable of extending their range into the sublittoral fringe by attachment to and growth on the shells of other animals, notably Saxostrea, Pomatoceros and Mytilus. Apart from the preference of E. modestus for wharf piles, neither barnacle shows any obvious sensitivity to a particular type of rock. Towards the more exposed coast end of the wave action scale, C. columna is aggregated in large numbers below a belt of C. brunnea, the upper boundary of which so often delimits the sharp, regular upper limit of the midlittoral zone (Plate 4, Fig. 2). As maximum wave exposure conditions are approached (McW3–6D4, Ta3) the small Chamaesipho disappears altogether and C. brunnea reigns supreme, its white shells visible for many feet into the supralittoral zone on rock walls subject to the full impact of a Pacific Ocean gale (e.g. Needles Point, Great Barrier, and Wha Wha, East Coromandel Peninsula). The fourth and largest common intertidal barnacle Elminius plicatus, unlike its other relatives, displays a discontinuous pattern of horizontal distribution. Perhaps surprising therefore is its wide tolerance of different types of substrate and wave-exposure conditions (cf. Cranwell and Moore, 1938, p. 387). In the present survey it was found as a dominant in the extreme shelter (McW3D2, Tb2) of the upper reaches of the Firth of Thames (Station 1) and also locally at the storm-battered Needles Point (Station 33), although in all cases the corrugated shells were attached to firm rock, rather than to movable boulders. Superimposed upon the basic creamy white of the balanoid zone are a number of colour contrasts provided in different localities by dull red Apophloea, red-black Bostrychia and Gelidium pusillum, bright grass-green Enteromorpha, and shining black hummocks of the small mussel Volsella (Modiolus) neozelanicus. Volsella is a local belt-former above half tide mark. All these save the Apophloea

Fig. 1—Station 21. Shag Rock Supralittoral zone, midlittoral zone and sublittoral fringe showing grey and yellow, black. barnacle and brown algal belts. Photo by R. M. Fig. 2—Miners Head. Northwest Great Barrier Island. Midlittoral marked by a regular white ribbon. of Chamaespipho and Elminius above and lithothamina below.

and Bostrychia belts disappear with the onset of open coast conditions. Enteromorpha nana on Little Barrier boulders is an exception. Despite its seasonal fluctuation in vigour, the vivid green Enteromorpha sward is too striking a feature in most seasons between M.S.L. and M.H.W.N. not to receive comment. E. procera f. minuta (or E. intestinalis where there is fresh or brackish water trickling over the rocks) is as typical of vertical wharf piles as it is of sloping or flat sandstone and basalt ledges devoid of barnacles. Possibly its most prolific growth is achieved on almost flat reefs where a certain amount of moisture is retained by the mat. In such places the community tends to be more persistent through the year. It responds quickly to continuous exposure by bleaching and dying of the tubular thalli. Tangled, spongy clumps of Gelidium pusillum are sometimes aggregated into a belt on their own or just below the finer textured plumes and branchlets of Bostrychia arbuscula and B. mixta, but nearly always modestly retreating to a shaded cleft or overhang. If G. pusillum does survive in the open it is mostly in association with some other organism, such as Volsella, from which it may derive moisture when exposed to sun and air. Nevertheless in a series of desiccation experiments (Dellow, M.A. thesis, unpub.) this spongy red alga was found to lose water at a much slower rate than other more light tolerant algae of lower levels—e.g., Scytothamnus and Corallina. Scarcity of Porphyra is a negative feature of the Gulf zonation. Seasonal growth of P. umbilicalis ? occurs in sheltered sandstone localities, but the community persists only from June until mid-September. Further out from land-protected shores P. columbina makes a sporadic appearance, though never in the profusion or attaining the dimensions of the thalli on the Auckland west coast (cf. Beveridge and Chapman, 1950, p. 191). No sun and shade forms were recognisable as at Piha; in fact any plants observed could be classified only as sun forms since they grew on directly insolated rocks or boulders, notably at Little Barrier, Wha Wha (east Coromandel Peninsula) and Sugar Loaf Rocks (Fig. 10). More widespread as a basic zone former is the leathery, crustaceous red alga Apophloea sinclairii, either admixed with barnacles, chitons and limpets or the only coloniser of bare rock between M.S.L. and about M.H.W.N. in situations where there is a fairly strong tidal current and little or no pollution Fertile thalli with erect projections were observed infrequently, the most common growth form consisting of the basal crust, often decaying in the centre or disfigured by the feeding of molluscs. Cranwell and Moore's (1938, p. 387) likeness of the patches of Apophloea, when dry, to congealed blood is an apt one; for the patches are seldom close enough to merge into one another. Apophloea is interesting in its absence from Waitemata Sandstone shores. There may be an antipathy on the part of sporeling stages to establishment on this type of smooth, easily croded stratum, since from its abundance on neighbouring shores (e.g., Leigh, Rangitoto) there would presumably have been opportunity for its settlement on the many bare sandstone surfaces about its particular tide level. The next prominent belt for the 2 feet below M.S.L. is the oyster belt, formed by Saxostrea glomerata in all situations with a certain amount of protection from direct wave action. The oyster belt is prominent on the East Coast mainland. It girdles most of the adjacent islands on their southern and western shores, and is physiognomic in sheltered harbours and bays of western Great Barrier and

Coromandel Peninsula, as well as on hard rock facies in the Upper Firth of Thames. Sensitive to excessive sedimentation and movable stones or boulders at the one extreme and to aeration and surf pounding at the other, it fades out at Te Puru, Howick, and again at Little Barrier, Sugar Loaf Rocks, and north-east Great Barrier. Saxostrea provides in its fluted, purple-fringed shells a home for barnacles, limpets, chitons, tube-worms and algae such as Caulacanthus spinellus, Centroceras clavulatum and Gelidium caulacantheum. Lepsiella scobina, the oysterboring gastropod, and also Neothais scalaris and Lepsia haustrum, have done untold damage to the commercial harvest. Harvesting and cultivation of rock oysters constitutes a major artificial biotic factor in the Gulf and on other wave protected North Island coasts. Not only are populations of Lepsiella, Lepsia and Neothais affected, but also those of Hormosira, which occupies wide stretches otherwise available for settlement of oyster spat. Marine Department records (1949–1951) indicate the numbers of borer (Lepsiella) and pupu (Lepsia, Neothais) destroyed annually; and the area cleared of dead oyster shells and Hormosira in connection with artificial oyster cultivation. A few figures* To the nearest 100. will suffice to illustrate the extent of this biotic interference which takes place each year in Kaipara Harbour, the Bay of Islands, Whangarei Harbour, Coromandel, Great Barrier and the Hauraki Gulf. Year. Oysters–sacks collected. Lepsiella scobina destroyed. Neothais Lepsia destroyed. Dead shells sq.yds. cleared. Hormosira sq. yds. cleared. Total Gulf 1949 5,000 700 1,204,900 700 1,400 1950 5,100 800 730,800 1,900 2,500 1,800 1951 4,200 800 1,429,500 1,800 900 9,100 In former years a number of square yards of rock were removed from high to lower levels in order to increase the space available for settlement of oyster spat. Over 100 square yards were transported during 1947–48, but no record appears after this date. Mussel (Mytilus canaliculus) populations are likewise considerably affected by commercial harvesting. The numbers of sacks collected at Auckland and Thames for the same years are as follows:— 1949 1950 1951 Auckland 9,400 9,400 11,800 Thames 3,400 3,700 4,400 Of the chief lower mid-littoral dominants there is still to be considered the distribution of Pomatoceros, Hormosira, Corallina and Xiphophora. The occurrence of Pomatoceros coeruleus is more difficult to correlate with a given set of habitat factors, since it dominates a number of widely divergent ecological stations—e.g., Narrow Neck, the Noises Islands, Little Barrier and Fletchers Bay. However, it fluctuates markedly in density from station to station, the most notable aggregation in the vicinity of sewerage outflows (Bastion Reef, St. Leonard's Point). In this connection it is interesting to recall the following supposition of Fischer-Piette (1936, p. 227) concerning the growth

of Pomatoceros triqueter on either side of the English Channel. “J'ai posé la question de savoir s'il ne fallait pas considérer que cette prospérité de l'espèce en certaines stations qui se trouvent tout être dans des baies étaient attribuable a une influence favorisante de substances organiques …” Sabellaria kaiparensis, the sand-tube worm frequently associating with Pomatoceros in the inner Gulf, is more restricted in distribution; and owing to its more easily eroded tubes it is less likely to be a basic zone former. Although a sheltered coast species on the east coast, it can evidently tolerate wild seas, since it has been reported as a co-dominant with Pomatoceros at Piha. Previous writers have made us familiar with the prolific growth of the Australasian genus Hormosira banksii on low-lying rocks of the midlittoral of semi-exposed to very sheltered coasts. The under-sized var. sieberi Harv. (= var. gracilis) is characteristic of pools and of growth on the lower midlittoral coralline turf. This variety can stand up to a moderate amount of lashing by surf at low tide, but is more conspicuous in water-filled depressions on reef surfaces not exposed to direct beating of waves. There appears to be an increase in size of bladders with increased shelter, shallower and more gently shelving shores, and greater turbidity. It was seen to be most prolific at Te Haruhi Bay, in lee of Whangaparaoa Heads, and Carnahan (1952, p. 38) notes H. banksii as replacing Saxostrea and C. columna ecologically at Rangitoto. He notes as well that the “button stage” may survive up to 1 foot above the upper limit of fully developed thalli. Such an effect is often demonstrated round margins of pools populated by Hormosira at higher levels in the barnacle zone. The buttons persist in the pool shallows and drainage channels which may dry up under excessive heat. Carnahan's experiments on water loss in Hormosira indicate an inverse rate of desiccation to the volume of each water-filled bladder or receptacle. Notheia anomala, the fucoid parasite associated with Hormosira, was not as widespread as might be imagined; in fact it was found on every host plant in only two localities, namely Motuihi Island and at Surfdale (Waiheke). Either associated with Hormosira or on its own, the cosmopolitan Corallina officinalis is the physiognomic turf component of moderately sheltered to moderately exposed, low-lying reefs. Like other wide-ranging dominants which are peculiarly sensitive to changes in vertical level (Dellow, 1950, Fig. 11), Corallina displays no limited preference for a certain type of substrate, being equally at home on sandstone, basalt and greywacke, both in pools and on exposed rocks. Loose stones and boulders are the only rocks on which it seems unable to support erect branches, although basal crusts abound on these. Growth may be quite normal where the water is clear, turbulent and well aerated (Station 10), but in general maximum development is achieved in situations where the Corallina-beds are subject to a certain amount of silt deposition from shallow, turbid water. The belt cuts out where estuarine conditions prevail— an analysis of its salinity tolerance would provide an interesting study. A suitable niche for germination and growth of many small red, green and brown algae is furnished by this coralline mat; and seasonal change in presence and abundance of the subordinate species is one of its distinctive features. Codium adhaerens var. convolutum is a frequent member of the community, with spring and autumn maxima (Dellow, 1953, pp. 239–246). Under the influence of shade

or surf, however, Codium may be elevated considerably above this level among Pomatoceros (Station 5) or barnacles (Station 33). Only repeated visits to the same area over a yearly period convince one that this velvety green belt of spongy, radiating thalli could not be sufficiently long-lived to contribute to the basic zonation of a Waitemata Sandstone coast. A light green contrast to the dingy pink of Corallina is provided by almost transparent tubes of Enteromorpha procera f. novae-zelandiae, by local cushions or reticulations of Microdictyon mutabile, and in darker crevices or overarched pools, by darker grape-like clusters of Caulerpa sedoides. In winter the turf may be hidden from view by a pale yellow-brown assemblage —not of Hormosira alone but of saccate Colpomenia sinuosa and perhaps the more gelatinous, convoluted thalli of Leathesia difformis. Deeper pink and red tonings are provided by Laurencias (L. botrychioides and L. virgata) and in shady pools and clefts, Plocamium spp., Cladhymenia oblongifolia, Symphyocladia marchantioides, Acrosorium decumbens and Myriogramme denticulata. A conspicuous molluse of the coralline turf is Lunella smaragda, the cat's eye (Oliver, 1923, p. 252). Once shallow, shelving shores are left behind and tidal platforms descend more abruptly into a clearer sublittoral, Corallina wanes in importance until it is completely replaced by other turf-forming red algae (the mixed algal turf community) dominated by species of Gigartina, Polysiphonia, Caulacanthus and Gelidium; by a Fucus-like band of light-brown Xiphophora; or by encrustations of whitish-pink lithothamnia. Mytilus canaliculus may also replace Corallina locally. Of these, Xiphophora takes precedence, since it is seen to dominate at almost every station where Corallina is lacking, especially in north and east sectors of the Gulf. Of course both genera can dominate in the one locality, Xiphophora flourishing on seaward slopes of rocks or boulders, Corallina taking charge on flatter reef surfaces and in shallow pools subject to gradual cover by rolling of broken waves, rather than to the direct force resulting as they break on the reef margin. Such a condition was observed at Wha Wha, an exposed station on the east coast of Coromandel Peninsula. Xiphophora itself is eliminated under conditions of maximal exposure (Needles Point). The presence of a belt of lithothamnia, like that of Xiphophora, is generally a reliable indication of an exposed coast subject to moderate or severe buffeting by waves. At stations intermediate in this respect (e.g., Leigh, Shag Rock) the thicker calcareous growths are confined to pools, and it is not until almost oceanic conditions prevail that the belt participates in the basic zonation of the community complex, as on the northern rugged shores of Great Barrier, and farther away to the north on Moko Hinau and the Poor Knights Islands. The absence of Novastoa zelandica from the lithothamnia belt south of these islands may indicate that it has reached the southern limit of its range. Cranwell and Moore (1938, p. 389) note a similar form, that of Stephopoma roseum, in a comparable ecological niche on the largest island of the Noises. Exposed to strong continual surge and sweeping currents, the small island in the centre of Oruawharo Beach (east coast, Great Barrier) was the only site examined where a typical West Coast Rhodophycean community occurs in the lowest midlittoral. Here Gigartina alveata and G. cranwellae are both dominants, the latter profusely intermixed with Pachymenia himantophora, Gymnogongrus nodiferus and Melanthalia abscissa.

Growth of Durvillea in the midlittoral* Durvillea antarctica is typically a member of the lower midlittoral—i.e., above M. L. W. M., not of the sublittoral fringe (cf. Chapman & Trevarthen, 1952, p. 201). at Needles Point, Great Barrier, confirming the verbal report of Miss H. M. Shakespeare (in Cranwell and Moore, 1938, p. 377), is essentially restricted to a few struggling colonies which fail to reach the vigour and abundance of their west coast relatives (Plate 3, Fig. 2). 4. Sublittoral Fringe Just as Chamaesipho columna is almost ubiquitous in the barnacle zone, so the sublittoral fringe of the Hauraki Gulf is distinguished practically everywhere by the profusely branched, blackish-brown fronds of Carpophyllum maschalocarpum. It is absent in fact only from rocks which have no sublittoral fringe (i.e., partially silted up areas) or where extreme to maximum wave exposure prevails. In the latter case it is replaced by C. elongatum (e.g., Sugar Loaf Rocks, Needles Point). Like Xiphophora, thalli which becomes established towards the upper boundary of its vertical range often appear stunted in growth, and are seldom fertile. From June to September, however, nearly all plants over a foot long display a prolific growth of tiny bunches of fertile receptacles in their “leaf” axils. Distribution of Carpophyllum plumosum is more puzzling, since it is a denizen of pools, and sheltered inlets and at the same time of the most rugged, storm-battered rocks. Surprisingly enough it has achieved profound dominance in the sublittoral fringe and the sublittoral on the wave and current-shifted boulders surrounding Little Barrier—a specialised habitat in which C. maschalocarpum has managed to obtain only a precarious foothold. Ecklonia radiata and its variety richardiana are also abundant locally in the fringe—however their massive unbranched stipes and tattered, bushy laminae are characteristically attached below tide levels, only the ragged heads and part of the stipes protruding at low water. Occasionally (Plate 2, Fig. 1) var. richardiana forms a belt on the seaward fringe of a sandstone reef in relatively shallow waters. The more robust, strap-like laminarian Lessonia variegata, the open coast equivalent of Ecklonia, is scarcely to be regarded as a component of the sublittoral fringe, although Lessonia does trespass above its watery canopy in isolated surge channels (Plate 3, Fig. 1). Cystophora and Sargassum are both represented in the fringe, usually as subordinates in varying degrees of abundance. Cystophora torulosa, the most common, sometimes dominates the upper fringe on the East Coast mainland, and in sheltered waters about the Noises and Waiheke. C. retroflexa is generally confined to low-level pools. Sargassum sinclairii may be encountered among Carpophyllum fronds in almost any locality except those most wave-beaten; and S. spinuligerum with its stumpy, blackish, spine-covered midribs is a feature of pool-depressed reefs at Browns Bay and Stanmore Bay. Beneath the canopy and among the holdfasts of these large brown algae which occupy the fringe between the tidal and tideless regions, a multitude of smaller plants and animals exist. Only a few can be mentioned here. On a groundwork of thin crustaceous corallines in which deeper pinks of Melobesia and shiny reds of Peyssonelia predominate one may fine coarse clumps of dark green Cladophoropsis herpestica, brown fan-like or strap-like thalli of Zonaria subarticulata,

or an abundance of Glossophora kunthii with its slender, furry, dichotomous branches. Common red algae include Pterocladia lucida, Melanthalia abscissa, iridescent Champia laingii in dense, creeping mats, C. novae-zelandiae var. dolichopoda, Plocamium spp., Myriogramme denticulata, Acrosorium decumbens and in rougher situations (e.g., The Pinnacles, Little Barrier), Cheilosporium elegans and C. corymbosum. Hydroids are numerous, both attached directly to bare rock between brown algal holdfasts and epiphytic on midribs and branchlets; e.g., Orthopyxis crenata, Plumularia spp. Sertularia spp. and Sertularella crassiuscula (cf. Kulka unpub.). Grey and orange sponges with red and white polyzoans find refuge in crannies where direct light never penetrates. Among the massive holdfasts of Ecklonia is a wealth of smaller molluscs, which constitute a specialised community in a specialised, restricted habitat. For much informative detail concerning the molluscs which occur in the littoral of the Hauraki Gulf the reader is referred to the accounts which appear by a number of student writers in the Auckland University College Field Club Journal Tane, between the years 1950 and 1952, to the local lists supplied by Oliver (1923), and to the masterly illustrated handbooks of A. W. B. Powell (1937,1947). 5. Sublittoral Zone Factors governing growth of permanently submerged communities differ profoundly from those producing vertical zonation in the intertidal region. Work has been done by Powell (1937) on bottom communities of animals in the Auckland Harbour, but the problem of algae remains practically untouched. Several algal records from shores of the Hauraki Gulf are purely from drift—e.g., Caulerpa hypnoides,* A report by Captain A. Duthie of a Caulerpa hypnoides bed at a depth of 14 fathoms off Katherine Bay, Great Barrier, needs confirmation. Cutleria multifida, Sporochnus, stylosus and Carpomitra costata. Of course this is no guarantee that they are confined to the sublittoral, and more intensive search may reveal them in littoral niches. Carpomitra however, is listed as a true sublittoral member by Lindauer (1947, p. 555). Certain brown algae which are typical sublittoral fringe inhabitants are known to occur in considerable quantities in the sublittoral proper, though not, as stressed previously (Part II, p. 21), in such pronounced horizontal bands. Table VIII has been compiled from records of specimens forwarded to the writer by R. Haxell of m.v. Ikatere. These brown algae were said to be dragged off the sea bed at the depths indicated, by a commercial type trawl. Table VIII. Records of Sublittoral Brown Algae in the Hauraki Gulf. Species. Date. Locality Depth Carpophyllum flexuosum (fertile) 25.7.50 Whangaparaoa passage 13 fathoms Carpophyllum flexuosum (fertile) 26.7.50 N.W. of Thumb Point, Waiheke Island 20 fathoms Carpophyllum plumosum 26.7.50 N.E. of Ponui Island 15 fathoms Sargassum sinclairii 25.7.50 Whangaparaoa Passage 13 fathoms Cystophora retroflexa 26.7.50 N.E. of Ponui Island 15 fathoms Cystophora retroflexa 25.7.50 Between Great Barrier (W.) and Flat Island 5 fathoms Halopteris hordacea 26.7.50 N.W. of Thumb Point, Waihere Island 20 fathoms More recently (17.9.53) the writer witnessed the dragging of specimens of C. maschalocarpum and Sargassum sinclairii in 7 fathoms, 2 miles north of Rangitoto.

B. Vertical Zonation From this regional survey it is apparent that on the rocky shores of the Hauraki Gulf there exist several clearly defined types of community complex, each associated with a certain kind of substrate. These will now be discussed, and compared with published reports from Piha and the Poor Knights Islands. In Figures 7-11 the writer has attempted to summarise the principal features of five representative coastlines in the Gulf. Each block diagram has been constructed in the first instance from a recorded traverse; but the symbols for the dominant or abundant organisms are arranged to indicate the most conspicuous features of that type of coast as a whole. Such a presentation is felt to be of greater value at this juncture than an exact replica of the zonation sequence at one restricted site of observation. The stations selected were: 1. Station 3 (Howick), an extremely sheltered Waitemata Sandstone shore, transitional between rock, sand and mud. 2. Station 5 (St. Leonards Point, one mile north of Narrow Neck); moderately sheltered Waitemata Sandstone, where tilted ledges form the shore. 3. Station 28 (Fletchers Bay), a greywacke coast in moderate wave exposure. 4. Station 29 (Sugar Loaf Rocks), a breccia substrate comprising a high level wave-cut platform and exposed to extreme wave action. Fig. 7. East Coast Mainland: Summary of Zonation at Howick a Waitemata Sandstone Coast in Extreme Shelter January 1950

5. Station 24 (Ti Titoki Flat, Little Barrier), a contrasting shore composed of loose boulders, and affected by moderate or strong waves and currents. 1. Howick (Fig. 7) The diagram illustrates the typical broad, gently shelving shore of sheltered sandstone areas, backed by stratified cliffs which in this case are quite heavily clothed with Pohutukawa (Metrosideros excelsa). Although the supralittoral zone and fringe are both recognizable from their respective dominants, the midlittoral is obscured for the most part by (a) a wide stretch of sand overlying the eroded rock strata, and (b) penetration of Zostera along the mud-silted depressions between parallel ledges. Absence of a Chamaesipho zone adds to the difficulty of defining the upper boundary of the midlittoral. Volsella, however, occupies its usual level on sandstone ledges close to the cliff. At lower shore levels there is no organism to distinguish a sublittoral fringe from a sublittoral zone, seeing that the change in dominance from Hormosira to Zostera takes place actually above M. W. N. It was decided therefore to omit the letters Ab, Bc, etc., used on other diagrams to indicate the junction between one zone and the next. Paucity in number of dominant species is a most significant feature of this type of shore, where the absence of the usual belt formers on Waitemata Sandstone is as striking an ecological fact as the presence of great sheets of Zostera at low levels. Saxostrea, Chamaesipho columna, Elminius plicatus and E. modestus are nowhere to be seen; and their absence is no doubt correlated as much with the heavy sand and mud deposits as with the reduction in direct wave action. Even Corallina, represented as it is by a few unhealthy patches, cannot tolerate such excessive deposition. From this type of shore it is but a brief step to the true mudflat where zonation is governed by a different factor complex (Chapman and Trevarthen, 1953, p. 200) and upon which the communities are seral in status. They range from Zostera at and below E.L.W.S. with its associated soft bottom groups like Amphibola-Helice and Chordaria-Potamopyrgus through a well developed Avicennietum, its pneumatophores and trunks supporting distinctive communities (e.g., Caloglossa-Catenella), to angiosperms of the salt swamp series, including the Stipa-Plagianthus, Festuca-Cynodon and Festuca-Ulex associes (Cooper, unpub.). 2. St. Leonards Point (Fig. 8) This headland, the northern limit of the previous (1947–48) survey of Narrow Neck, displays more of the range of features of the East Coast Mainland than the majority of other similar stations examined. Again one is confronted by an extensive littoral, broken up by a series of tilted ledges with their dip faces slanting towards the bare cliffs and the more or less vertical strike faces confronting the sea. The three-dimensional picture brings out not only the vertical limits of each species, but also the preferences of each organism for a particular type of configuration—e.g., that of Gelidium pusillum and Pomatoceros for vertical faces, and of Calothrix, Enteromorpha, Corallina and Saxostrea for strongly lighted surfaces of gentle slope. The tilt of the series of ledges, governed by the degree of folding of the adjacent cliff strata, complicates the zonation pattern considerably. Thus with a ledge tilted to say 30 degrees, a series of belts will be present on the upper surface, each belt coinciding with its appropriate tide levels. The strike face of the same ledge will probably be masked by a

Fig. 8. East Coast Mainland: St. Leonards Point Summary of Zonation on Waitemata Sandstone Ledges in Moderate Shelter. totally different population. Figure 8* In this diagram seasonal communities have been omitted, since their occurrence is known with more certainty than at other stations, and has been recorded in Part II. supplies numerous instances of such banding. The vertical sequence is familiar: a supralittoral fringe with Calothrix and Melaraphe, the latter roving over dip and strike faces; a midlittoral divided into several belts, or subzones, as follows: a green Enteromorpha sward; the wide-ranging Chamaesipho columna cropping up at high and low levels together with some Eliminius plicatus and E. modestus; the shining black Volsella belt, subtended by a strike face riddled with Pholadidea holes; an oyster belt, many of its shells clinging to the reddish upstanding limonite joints; a white band of jagged Pomatoceros tubes mostly restricted to strike faces; and finally the dull pink Corallina turf, admixed with small Hormosira and fringed on seaward edges by blackish green cushions of Codium adhaerens var. convolutum. Dark brown Carpophyllum maschalocarpum and C. plumosum holdfasts are the most obvious indicators of the commencement of the sublittoral fringe. In this zone the thalli of these Phaeophyceae are short in comparison with the length achieved by the same species in the sublittoral proper. Mytilus is conspicuous at E.L.W.S., though sparsely scattered in the Corallina turf above. Encrusting corallines are a feature of the fringe, but by no means confined to it. Only in the sublittoral zone do the bulky laminarian Ecklonia thalli reach their normal dimensions.

Zonation indicators of neighbouring shores conspicuous by their absence are Apophloea, which has not managed to establish its crusts on the smooth, often slippery, sandstone, and Xiphophora, a denizen of clearer waters and more open coasts. 3. Fletchers Bay (Fig. 9) From the location of Fletchers Bay on the extreme northern stretch of Coromandel Peninsula one might suppose it to be too exposed to display a community Complex representative of many rocky headlands inside the Gulf. However, Fletchers Bay is protected from the full impact of Pacific Ocean gales by Great Barrier Island, some 15 miles to N.N.E., and locally by a wide reef projecting at the eastern end of the bay. On the other hand, the sublittoral quickly descends to 18 or more fathoms off Cape Colville to the west, and gales may still strike this shore with considerable force. The traverse from which Figure 9 was constructed is interesting in that it crosses the boundary of the supralittoral fringe at three different places, the large rock mass in the centre providing sufficient protection to encourage growth of shelter-preferring algae in the channel intervening between it and the cliff, while on its seaward slopes flourish forms typical of an open coast. The greywacke substrate resembles that in many other localities—e.g., rocky promontories from Raukura Point (N.W. Firth of Thames) to the west coast of Coromandel Peninsula, and also Shag Rock, the Noises and northern Waiheke Islands. The rock surface is extremely hard and roughened by irregular, angular joints among which a relatively great number of plants and animals find a suitable niche. There is no predominating organisation of eroded strata into ledges, as on sandstone shores, rather a series of broken rock-masses which appear more regular owing to the banding of their dominant organisms. In the supralittoral zone crustaceous Verrucaria and Hildenbrandtia and tufts of Lichina are confined to cracks and crevices, accompanied by the littorinid Melaraphe. The fringe supports an increased population of the two latter, and there is a notable absence of Myxophyceae. The commencement of the midlittoral is marked unmistakably on both inner and outer margins of the traverse by a foot-wide belt of scattered Chamaesipho brunnea. C. columna follows in fairly dense patches from M.H.W.N. on the protected, and E.H.W.S. on the exposed face, down to below M.T.L. Within the barnacle zone, again several subzones are recognizable. Shielded by a certain degree of overhanging rock, Bostrychia enters between the two Chamaesipho species on the wall facing directly to seaward. Crustaceous forms delimit the other subzones; first a broken, blood-red belt of Apophloea, extensive patches bearing fertile branchlets towards its lower limit; and then an intermittent stretch of whitish-pink lithothamnia which becomes more clearly defined immediately below C. columna. Superimposed upon the former are stellate clusters of tiny red-brown Chaetangium corneum—a zonation feature apparently peculiar to Fletchers Bay. Ralfsia crusts are abundant, interspersed among or growing upon the lithothamnia, but Pomatoceros and erect Corallina are on the wane, being represented by a few scattered shells and clumps. Like most other coasts of similar substrate and wave-exposure index, the lowest midlittoral at Fletchers Bay is bounded by a dense fucoid band of Xiphophora, its mature fronds trailing well below into the sublittoral fringe. The sublittoral and its fringe are both more sparsely populated than usual at this point, there being no pronounced belt of Carpophyllum maschalocarpum below Xipho-

Fig 9 Northern Coromandel Peninsula Summary of Zonation at Fletchers Bay on Pre-Jurassic Greywacke, in Moderate Wave Exposure - May 1950. phora, perhaps due to the broken configuration. C. plumosum, however, is abundant, and with C. flexuosum and Ecklonia it constitutes the bulk of the sublittoral population. Sheltered coast dominants which are absent from this locality include Myxophyceae, Volsella and Elminius modestus. Saxostrea, Pomatoceros and erect Corallina are poorly represented. On the other hand a few shelter-lovers, such as Hormosira, Gelidium caulacantheum, Pylaiella and Corallina maintain a healthy pool-existence in the moist or water-filled channel protected by the elevated rock-mass in the middle of the traverse. 4. Sugar Loaf Rocks (Fig. 10) Not until the Coast is completely unprotected by any neighbouring island or stretch of mainland does a more simplified and regular horizontal pattern of zonation become apparent. Such is amply illustrated in the Sugar Loaf Rocks sequence, where the littoral topography has been moulded into a high spring tidal wave-cut platform hollowed out from the base line of the less resistant breccia cliff, and an undulating series of rounded steps at the seaward margin of the platform towards the sublittoral, finally to plunge almost vertically far into the depths below. By comparison with more sheltered shores, the intertidal region here is foreshortened to a noticeable degree. The surface of the wave-cut platform is covered with mounds of cemented stones and smoothly rounded boulders, among which tiny runnels wind their way

Fig. 10. North-Eastern Coromandel Peninsula: Summary of Zonation at Sugar Loaf Rocks on Breccia in Extreme Wave Exposure May 1950. Ab-Supralittoral Zone Bc-Supralittoral Fringe Cd-Midlittoral-Barnacles De-Midlittoral-Algae Ef-Sublittoral Fringe into shallow pools, where tufted Enteromorpha, Pylaiella and wrinkled Placoma find a refuge. Most of the platform surface is bare, but a closer inspection shows that the usual Lichina-Melaraphe community is present, and elevated above the supralittoral fringe along the numerous cracks in the broken cliff face. Nerita is also abundant. Marked by a slight elevation of the cemented boulders, the seaward fringe of the platform segregates the midlittoral sharply from the supralittoral fringe. Chamaesipho brunnea abounds on the steep face as the uppermost belt, in greater numbers than at Fletchers Bay. C. columna is equally pronounced in its boundaries, although not covering every square inch of the space available. Bostrychia again haunts the shaded crevices and overhangs. One or two Porphyra columbina thalli hang inconspicuously from rocks in the upper C. columna zone—doubtless a seasonal appearance. Enteromorpha, Caulacanthus, Gigartina alveata and Splachnidium have established themselves firmly on flats about M.T.L. where at low tide they have a chance of being kept moist by surge and splash. Nemastoma oligarthra forms a narrow, dotted band below C. columna, and encroaches on the lithothamnia belt in some places. A mosaic effect results from the patchwork of short, turf-forming algae (Ulva lactuca, Laurencia thyrsifera, Gigartina sp.) which dominate mainly on the flatter rock surfaces, but occupy less space in general than thick, crustaceous lithothamnia. Represented by a few young and mature thalli, the Xiphophora belt has waned in importance, although still a conspicuous feature in the major zonal pattern.

In the sublittoral fringe Carpophyllum elongatum holds complete sway. By contrast in the sublittoral proper, Lessonia crops up only at odd intervals, its presence betrayed by the straps of its laminae which are buoyed up to the surface of the water at low spring tide. 5. Ti Titoki Flat (Fig. 11) The figure represents zonation on the boulder spit of S.W. Little Barrier near the caretaker's residence. Viewed from a distance, a gently sloping supralittoral zone abuts on to soil or adlittoral vegetation. The boundary between the two is marked by a wall of large flax (Phormium tenax) bushes, isolated trees or shrubs of Pohutukawa (Metrosideros) and a tangle of Muehlenbeckia complexa straggling over the uppermost boulders. Euphorbia glauca grows locally between boulders coated with grey lichens (Ramalina, Parmelia and crustose spp.). All these plants flourish within a few feet of E.H.W.S.,* Tide levels are only approximate, owing to insufficient data from which to estimate averages. Intermediate levels, therefore, have not been indicated in Figure 11. and are liable to be drenched with spray in a heavy gale. Boulder size decreases appreciably below E.H.W.S. on the storm bank which continues down to about half tide-mark. No barnacles have obtained a foothold on this, their normal position on a rocky shore. A handful of black-shelled Nerita roam over the naked stones, but beat a rapid retreat into the moist spaces below the surface as rock temperature rises in bright sunshine. The spit is a shore which may be said with conviction to belong almost exclusively to the algae, since below half tide there is not a single exposed belt dominated by shelled animals. A green sward of Enteromorpha nana is conspicuous, not as an unbroken sheet but covering the upper domes or flat surfaces and sides of boulders, the whole creating an illusion of unity as it fades along the shore in the distance. Light brown circular patches of Ralfsia and Hapalospongidion are the next dominants to be disclosed by a receding tide; followed closely on seaward slopes by Nemastoma and lithothamnia—both thick and thinner crusts intermingling. The algal turf, that green, brown and red cover so typical of the Little Barrier lower midlittoral, vies for space with the lithothamnia. The boundary between the two communities fluctuates in a manner seldom observed on a coast with a more uniform substrate. At its first appearance confined to the lower, sun-sheltered sides of boulders, the turf gradually covers their upper surfaces with decrease in level of the shore to what corresponds with the sublittoral fringe. Here Xiphophora takes precedence, associated with or just above a profuse growth of the more slender dichotomies of Glossophora. At E.L.W.S. Carpophyllum plumosum gradually ousts the other dominants, even C. maschalocarpum, except for a dense growth of Spatoglossum on a few boulders. Boundaries between the zones of a consolidated rocky shore have not been indicated in the diagram, although the terms have been used in the same sense in the text, for convenient reference. There is no organism to mark the upper limit of the midlittoral or of the supralittoral fringe, but lower littoral communities are still noticeably confined to their respective tide levels, despite the broken nature of the surface. As usual, Xiphophora appears to mark the upper boundary of the sublittoral fringe, while that of the sublittoral zone is indicated by the site of attachment of Carpophyllum plumosum holdfasts. These subdivisions, then, are as much as reality as they are on more homogeneous substrates,

Fig. 11. Little Barrier Island: Summary of Zonation at Ti Titoki Flat on Upper Surfaces of Loose Boulders, in Moderate to Extreme Wave Exposure - October 1969. E.h.w.s.-About 8,0 Feet Above E.l.w.s but they are obscured by the broken surface configuration and irregular banding which may be caused either by the sucking back and welling up of the sea in between the boulders, or by occasional changes in the alignment of the boulders. Relationships With Other North Island Stations Since but two other detailed accounts of zonation on North Island coasts have been published—i.e., those for Piha (Beveridge and Chapman, 1950) and the Poor Knights Islands (Cranwell and Moore, 1938) a direct comparison of Hauraki Gulf zonation will be made with these. All three localities are in similar latitudes, and so it might be expected that zonation contrasts will be sharper with the west coast than with the east. (a) Piha Community complexes such as those at Sugar Loaf Rocks and Needles Point, Great Barrier, are the only ones in Hauraki Gulf waters which bear a close similarity to those on the rugged west coast, at places like Piha and Anawhata. Differences in specific dominance and ecological balance on the east and west coasts of the Auckland district must be associated in some measure with oceanographic conditions such as turbulence, depth of off-shore water, oxygen, phosphate and nitrate content, as well as with average and extreme climatic data. It is a well-known fact that water temperatures on the Auckland west coast are sensibly cooler to bathers than those on the shallow, sandy stretches of the more sheltered east coast. Further research is required to investigate the quantitative nature of these physical factors, including the possibility of upwelling in connection

with the cooler west coast water. Dense greenish brown sheets of phytoplankton observed on these shores, but never on the corresponding east coast, may well be positive biological evidence of such a phenomenon. Both shores are allegedly swept by the Notonectian Current, which flows in a northerly direction along the west coast, turning south again after it rounds the tip of the North Island at least as far as the Hauraki Gulf. The immediate offshore depths on both coasts are not much different except in the shallows inside the Gulf, where the water is subject to more extreme heating and cooling. Since the Hauraki Gulf stations do not differ appreciably in latitude from Piha it is unlikely that any differences in vertical limits of species common to both can be attributed to this factor (cf. Gislén, 1944; Knox, 1953). Although both east and west coasts are affected by prevailing westerly winds, the effect of the latter is of course totally different. On the west coast the direction is onshore, and the amount of wind-blown spray is great enough to give an impression of haze in the distance. The biological response is seen in an upward displacement of several dominant zones (cf. Beveridge and Chapman, loc. cit., Figs. 13, 14). On the east coast prevailing westerlies carry a low tide out below the predicted level, thus increasing the length of time littoral organisms are exposed to the possible effects of desiccation. Wind-blown spray is carried out to sea, rather than high up into the supralittoral. Naturally the situation is reversed during north-easterly gales, but these are relatively infrequent. Apart from problems of geographic distribution, the main ecological differences between the two coasts appear to be associated not only with the actual degree of turbulence, but also with its duration. The west coast is pounded almost continually by heavy ocean breakers—the east coast suffers merely intermittent gales of force 6 and over. Algae appear to be more sensitive in their relations to this factor than the dominant attached animals, most of which (except Novastoa zelandica) appear in comparable quantities on both coasts. North Island west coast algae poorly represented or absent from the corresponding east coast include Porphyra columbina, Gigartina marginifera, G. atropurpurea, G. alveata, Stenogramma interrupta and Durvillea antarctica. Conversely, dominants of the North Island east coast which are scarce or lacking on the west include all the Carpophyllum species, Glossophora kunthii, Xiphophora chondrophylla var. minus, Hormosira banksii, Ecklonia radiata and Lessonia variegata (cf. Moore, 1944a, Table II). In other words the chief differences in specific composition lie among the large brown algae of the lower midlittoral, sublittoral fringe and sublittoral zones. Other typical east coast communities apparently scarce on the west coast are the high level group of Myxophyceae, and the short algal turf below the barnacle zone. While Apophloea is not listed as a dominant at Piha by Beveridge and Chapman, it is recorded as such among representative “association” complexes by Cranwell and Moore (1938, Table I) from Anawhata, not far to the north. (b) The Poor Knights Islands In comparing the community complexes at Sugar Loaf Rocks and the Poor Knights, the only major dominants absent from the former are Novastoa and the sublittoral Rhodophyceae. Verrucaria and Myxophyceae were not found on these particular rocks, but it is quite possible that a more detailed search would reveal their presence, especially if made at a different season. (Verrucaria was recorded from shaded crevices in the supralittoral at Fletchers Bay, some two kilometres

westward.) Similarly, Apophloea was not recorded in the vicinity of the traverse, although noted less than a kilometre from its location. The harder rock and vertical faces of the Poor Knights coastline are more directly comparable with those at Needles Point, Great Barrier, where the vertical Table IX. Dominants of Community Complexes at Five Representative Stations in the Hauraki Gulf in Comparison with those at Piha and the Poor Knights Islands. Zone Species Howick St. Leonards Pt. Fletchers Bay Sugar Loaf Rocks Ti Titoki Flat Little Barrier Poor Knights Piha Sublittoral Zone Metrosideros excelsa + + + Phormium tenax + Euphorbia glauca + Muehlenbeckia complexa + Mesembryanthemum australe + Grey and yellow lichena + + + Melaraphe oliveri + + + + Lichina pygmaea + + + Verrucaria + + Myxophyceae + Supralittoal Fringe Melaraphe oliveri + + + + + + Lichina pygmaea + + + Calothrix scopulorum + + Rhizoclonium riparium + + + Bostrychia arbuscula + + Midlittoral Zone Chamaesipho brunnea + + + + C. columna + + + + + Enteromorpha procera f. minuta + + + Boetrychia spp. + + Gelidium pueillum + + Apophloea sinclairii + Volsella neozelanicus + + + Elminius moderatus + E. plicatus + + + + + Saxostrea glomerata + + + Pomatoceros coeruleus + + + + Sabellaria kaiparaensia + + Ralfsia verrucosa + + + + Hapalospongidion saxigenum + Lithothamina + + + + Thin encrusting corallines + + + + + Hormosira banksii + + + Novastoa zelandica + Corallina officinalis + + + Algal turf + + Xiphophora chondrophylla var. minus + + + + Gigartina alveata + + + Pachymenia himantophora + Gigartina spp. + Durvillea antarctica + Mytilus canaliculus + Gelidium caulacantheum + + + Codium adhaerens + + Zostera nana + Sublittoral Fringe Carpophyllum maschalocarpum + + + C. plumosum + + + C. elongatum + + Ecklonia radiata + Glossophora kunthii + Rhodophyceae + Mytiluse canaliculus + + Zostera nana + Sublittorial Zone Carpophyllum plumosum + + + C. flexuosum + + Ecklonia radiata + + Lessonia variegata + + Rhodophyceae + + Zostera nana +

sequence indicates maximal wave exposure in one or two places by the presence of Durvillea antarctica above Carpophyllum elongatum (Plate III, Fig. 2), and of a restricted Rhodophycean community dominated by Vidalia colensoi and Pterocladia lucida in the sublittoral (cf. Table IX). Further mention should be made of Table II in Moore's (1944a) discussion of the ecology of the New Zealand species of Pterocladia. In a series of “association” complexes the principal dominants on both east and west coasts of the North Island are listed as they occur most usually on exposed rocky headlands. This table serves as well to emphasize geographic range changes on different parts of the coast; and attention is drawn to notable absences or paucity of algae prominent in other districts. An appreciation is shown (p. 195) of the important differences which ensue in passing from the exposed headlands to more sheltered platforms which are so typical of the north-east coast of the North Island, and upon which, in the lower midlittoral, Hormosira and Corallina are physiognomic. C. Comparison With Rocky Coasts Beyond New Zealand 1. Geographic Status of the Flora and Fauna Much valuable data has been accumulated by various New Zealand workers in the field of systematics and geographic relationships about marine plants and animals, concerning both restricted groups and the occurrence of a faunal and floral provinces (cf. Powell, 1937; Moore, 1949). However, from an ecological as well as a geographical standpoint, T. A. and A. Stephenson (1950, p. 318) hold the opinion that the distribution of ecologically important communities— i.e., the intertidal biota considered as a whole, is most likely to be a natural guide to a true knowledge of geographical provinces. The Hauraki Gulf falls roughly in the centre of the area recognised by Moore as the Auckland province, which extends on the east coast from the tip of the North Island to East Cape, and reaches a comparable latitude on the west. According to Powell's subdivision, the Gulf lies in the north-easterly sector of the Cookian Province, which occupies most of the North Island, and is bounded on the east coast in the north by the Bay of Islands and in the south by Banks Peninsula. Powell, however (ref. in Hornibrook, 1952) has signified his intention to lower the east coast boundary of his northern Aupourian province to East Cape, in which case the Gulf would be classified, probably more naturally, in the same algal and molluscan provinces. Setchell (1915—1920) discusses the relationship between mean maximal and minimal sea temperatures and the distribution of marine algae. On his view, the summer isotheres and winter isocrymes of 0, 5, 10, 15, 20 and 25° C. are significant, and the majority of species have an upper range of temperature tolerance varying over not more than 5° C. In general, the total temperature range of one algal species lies within 10° C. Accordingly the world is subdivided into zones following the summer isotherms corresponding with these figures. From the angle, the system of Ekman (1935—Ref. in Stephenson, 1947) has been widely adopted for application to littoral (i e., intertidal) regions, and it is proposed to follow his classification here. Charts II and III from Svederup, Johnson and Fleming (1942) show that in summer (February) the Gulf lies just south of the 20° C. isotherm. The corresponding West Coast is north of the same isotherm. which curves to the south, west of North Cape. In winter (August) both east and west coasts of the Auckland district are traversed by the 14° C. isotherm. Thus

we have roughly to consider an area which undergoes an annual sea temperature range of 6° C., between the isotherms of 14 and 20° C. Stephenson (1947, p. 215) describes a warm-temperate fauna as one occurring where winter sea temperatures fall below 20, but not below 10° C. Maximal summer temperatures are about 25° C. A cold temperate fauna on the other hand tolerates winter temperatures below 10° C., but generally above zero. Considering now the sea temperature data collected in this survey it appears that within the relatively shallow area partially enclosed by the Gulf, inshore temperatures show a wider range of variation, as might be expected. The extreme recorded maxima and minima were 23.5 and 12.2° C. respectively, giving an annual range in the order of 11° C. If criteria for the faunal temperature boundaries as described by Stephenson (1947, pp. 214–215) were applied to the Hauraki Gulf, these figures would undoubtedly place it in the category of warm-temperate, seeing that the known maxima and minima fall within the limits of 10 and 25° C. T. A. and A. Stephenson (1952, p. 11) contend that such a population should consist mainly of eurythermic species with subtropical or tropical affinities, with possibly a smaller element of cold-temperate forms, but lacking stenothermic tropical and antarctic elements; although these latter could be represented by seasonal species. In the present work it is not intended to analyse the geographic components of the Hauraki Gulf fauna and flora in detail. The range of distribution of most of the dominant species is given in Appendix II. Since subordinate members have not been considered it is not possible to draw conclusions from the numbers represented in each geographic category. However, it is apparent from this list that certain elements are represented more strongly than others. The chief elements present include: (1) Endemic species confined to the north of New Zealand. (2) Endemic species ranging throughout New Zealand. (3) Non-endemic species confined to northern New Zealand. (4) Non-endemic species occurring throughout New Zealand. (5) Non-endemic species occurring mainly in the south of New Zealand. (6) Cosmopolitan species. (7) Winter- and summer-seasonal species. Group 1, the northern endemic element, is strongly represented by such species as Saxostrea glomerata. Chamaesipho brunnea, Pholadidea spp., Carpophyllum plumosum, C. elongatum, Gigartina alveata and G. laingii. Wider ranging endemics in Group 2 are also common—e.g., Carpophyllum maschalocarpum, Bostrychia arbuscula, Gelidium caulacantheum, Hapalospongidion saxigenum, Codium adhaerens var. convolutum (to Lat. 44° S.), Melaraphe oliveri, Pomatoceros coeruleus and Elminius plicatus. Non-endemic species in New Zealand not occurring south of Cook Strait (Group 3) include Enteromorpha procera f. minuta, Sargassum spinuligerum, Halopteris hordacea, Hormosira banksii f. sieberi and Nerita melanotragus. Among the dominant species not confined to New Zealand (mainly Group 4) relationships with Australia are much closer than those with western South America (cf. Laing, 1927). Typical Australasian species are Hormosira banksii, Ecklonia radiata, Carpophyllum flexuosum, Cystophora torulosa, Halopteris hordacea and H. spicigera (cf. Moore, 1953). Fewer species extend their range over the South Pacific Ocean to western South America—e.g., Scytothamnus

australis, Splachnidium rogusum, Glossophora kunthii, Durvillea antarctica and Lessonia variegata. Durvillea and Splachnidium, of course, are not confined to New Zealand and South America. Splachnidium is one of the few algae occurring also at South Africa, as well as in Australia and many other islands in the temperate southern hemisphere (cf. Chapman, 1953). Southern species which belong to the subantarctic element and occur at outposts in northern New Zealand (Group 5) include only Durvillea antarctica and Lessonia variegata. Winter occurrence of Porphyra spp. is probably an extension of this element. In the cosmopolitan group 6 we find the lichens Lichina pygmaea and Verrucaria, as well as Myxophyceae like Calothrix scopulorum, green Rhizoclonium riparium and Ulva lactuca, and also crustaceous Ralfsia and lithothamnia. This group contains a number of forms which are seasonal in their Hauraki Gulf appearance—namely Scytosiphon lomentaria, Colpomenia sinuosa and Leathesia difformis. From the above the Gulf emerges as a region with a strong and characteristically northern endemic element in its major littoral biota, including fairly prominent Australian and cosmopolitan sections. Although a very much reduced element is present which is characteristic of subantarctic biota (Skottsberg, 1941, pp. 75–80) on the west coast of South America, nevertheless truly subantarctic dominants are rare. It will be noted that only species are discussed here. The situation may appear in a different light when a large number of genera are considered, as Laing has done in his 1927 account. New Zealand has obviously been isolated for a sufficient length of time for the evolution of a great many species, but generic connections are still strong with Australia, and to a lesser extent with South Africa and South America. One of the major facts resulting from the present survey is the relative paucity in numbers of algae, in comparison with records made by workers on other coasts. In a recent publication H. B. S. Womersley (1950, p. 137) lists 401 algae from Kangaroo Island, South Australia. A further 100 are still to be described. In the Hauraki Gulf, coastline of comparable magnitude with that of Kangaroo Island, the writer records only 241 species of algae (Appendix I). This figure does not include varieties or forms of the same species. Womersley collected between the years 1944 and 1949, and the writer's records are made over a fiveyear period between 1947 and 1951. The species analysed are distributed among the different algal groups as follows: Kangaroo Island Hauraki Gulf No Common to both Myxophyceae 26 28 11 Chlorophyceae 46 45 9 Phaeophyceae 96 46 15 Rhodophyceae 233 122 16 Total 401 241 51 The numbers of blue-green and green algae almost coincide, but there is a wide discrepancy among the brown and red groups, in both of which the Hauraki Gulf populations are reduced by about half. Inshore temperatures about Kangaroo Island are slightly below Hauraki Gulf records. Womersley (1947, p. 234) notes a variation between 11° and 20° C. Taking into account the ecological differences between the two areas arising from

the fact that Kangaroo Island lies at least 10 miles out from the mainland and is washed by a strong westerly current, it is probable that the greater number of species and richer crop production (cf. T. A. and A. Stephenson, 1950, p. 395) which is inferred from Womersley's (1950) account, is connected to some extent with conditions resulting from slightly lower temperatures and more boisterous, highly oxygenated seas. But it could also depend on the presence of a greater variety of ecological niches round the shores of Kangaroo Island provided on coasts which are extremely exposed to north, west and south and extremely sheltered to the north-east (cf. Womersley, 1947, Fig. 4). In marked contrast Stephenson (1947, p. 293) found an increase in numbers of algal and animal species present from colder west to warmer east coasts of South Africa, the algae showing the trend less strongly than the animals. Solely on the basis of temperature, therefore, one would expect the numbers of Gulf algal species to be at least as high as those for Kangaroo Island. Obviously some other factors must be adverse for prolific algal growth in this region. Some of those factors may well be increased turbidity associated with a shallow, shelving shore in many districts, a lack of turbulence from direct wave action, plus a certain amount of organic pollution from the numerous sewage outflows, especially in the Auckland Harbour. Evidence in support of this assumption comes from the reports by T. A. and A. Stephenson (1952) of a reduction in numbers of common species of both plants and animals at Charleston, a sheltered harbour on the Atlantic seaboard of North America where pollution is extreme. 2. Relation of Zonation in the Hauraki Gulf to that in Other Countries The geographic and ecological status of the dominant organisms may be tested further by studying zonation sequences recorded in other parts of the world, where temperature and habitat conditions are similar. From the ever-growing literature concerning this topic in both hemispheres, those localities most closely related in their physical features and the nature of their biota have been chosen for comparison. Southern Hemisphere coasts which have been selected are those of New South Wales (Dakin, Bennett and Pope, 1948) and the southern coast of South Africa (Stephenson, 1944). In the Northern Hemisphere points of resemblance may be seen from Central Japan (Gislén, 1943) in the north-west Pacific, and on the Atlantic coast of North America at Beaufort, Marineland, Florida and North Carolina (T. A. and A. Stephenson, 1952). (a) Southern Hemisphere After considering the accounts of Dakin, Bennett and Pope (1948) for New South Wales, Bennett and Pope (1953) for Victoria, Guiler (1949) for Tasmania and Womersley (1947, 1948) for Kangaroo Island, it was decided to select the New South Wales account for direct comparison of the Hauraki Gulf with Australian shores. This does not imply that there are no points of resemblance with the other areas, but simply that New South Wales and the Hauraki Gulf have the greatest number of features in common. Similarly from the great South African survey of Stephenson and his co-workers (1939–1947) the southern coast appears to be more directly comparable with this part of New Zealand than either the east or west coasts. Sea surface temperatures are highest off the South African coast. An average range of about 18 to 24° C. is apparent from the diagram on p. 253 of Stephenson's

1947 paper. These records were made 10 miles out from the coast. Dakin's records (1948, Fig. 2), also well out (4 miles from Sydney) show a monthly minimum of 16 and a maximum of 23° C. Disregarding inshore records for the sake of uniformity, the figures averaged from coastal vessels inside the Hauraki Gulf indicate a range of 15° to 20° C. This is in substantial agreement with the August and February sea isotherms bounding the region. If these figures can be regarded as comparable, then it appears that New South Wales has a similar lower limit of temperature range with the Hauraki Gulf, and a similar upper limit to the southern coast of South Africa. The latter is bathed by considerably warmer waters than the Hauraki Gulf, although all three regions are classed as warm-temperate. On the basis of temperature, zonation on the New South Wales coast might be expected, therefore, to show features intermediate between those displayed in the Hauraki Gulf to the south-east, and westward on the southern coast of South Africa. An examination of Table X indicates that to a certain extent this is so. In all cases, superimposed upon the basic zones of littorinids, barnacles and sublittoral fringe are a number of subzones, each characteristic of the region, and the degree of wave-exposure. New South Wales shares its sheltered coast barnacle, Chamaesipho columna, its fucoid Hormosira banksii and its laminarian Ecklonia radiata with the Hauraki Gulf, also Pterocladia capillacea as a subordinate in the Gulf. Pyura, though recorded by Brewin (1951, p. 104) from Leigh and Takapuna, is not, generally speaking, a dominant belt-former in the Gulf lower littoral (contrast Dakin, Bennett and Pope, loc. cit., p. 195). Galeolaria is represented in New Zealand by Pomatoceros in the lower midlittoral of New Zealand, and in South Africa by Pomatoleios. The New South Wales exposed coast barnacle Tetrachta has its counterpart in more sheltered Cape regions, but Pyura is a major feature of the sublittoral fringe in both regions. Resemblances between the Hauraki Gulf and Cape sequences are to be seen in the presence of a short algal turf community in the lower midlittoral, typical of exposed coast localities in New Zealand, but of moderate shelter at the Cape. From Column II of Dakin, Bennett and Pope's Fgure 3, the presence of Corallina in a very exposed sequence is in contradiction to that in the Gulf, where it is generally a sheltered coast dominant of low-level platforms. Each of these shores has in addition certain belts which have no counterpart on the other two coasts. In the Hauraki Gulf the belts of Volsella (Modiolus), Elminius plicatus, Saxostrea, Xiphophora and Carpophyllum spp. may be cited. However, other parts of Australia and also North America are known to possess similar forms. For instance, Xiphophora chondrophylla is noted by Womersley (1953, p. 159) as occurring “in patches in the upper sublittoral”; and Bennett and Pope (1953, p. 120) draw attention to a band of Modiolus pulex in the upper Chamaesipho zone on the colder Victorian coasts. (b) Northern Hemisphere Because of a lack of uniformity in methods of description among writers direct comparison with northern hemisphere shores is more difficult. Nevertheless valuable comparisons can be drawn from several accounts, foremost among which are the Stephensons' descriptions of the Atlantic coast of North America from Cape Canaveral to Cape Hatteras (1952). In the north Pacific Ocean, Gislén's (1943) comparison between the coasts of central Japan and California is a profitable source of information, despite the fact that it is written without

Table X. Relationship of Warm-Temperate Zohation in the Southern Hemisphere to the Standard Standard Zonation New Zealand: Hauraki Gulf Australa: New South Wales South Africa: South Coast Supralittoral Fringe Zone after T.A. and A. Stephenson, 1949. after Dakin, Bennett and Pope, 1948. after Stephenson, 1944. sheltered exposed sheltered very exposed sheltered exposed grey and yellow zone Melaraphe littorinids Tetraclita Littorina littorinida black zone Melaraphe black zone black zone littorinids littorinids Tetraclita Littorina Porphyra Midlittoral Zone barnacles C. columa Volsella Apophloea E. plicatus Saxostrea Poxatoceros Hormosire Coralling encrusting C. brunnea C. columna E. plicatus C. columna lithothamis short algal turf Xiphophora C. columna Tetraclita Galeolaria Tetraclita Catophragmus Corallina Pyura Pterocladia Pyura Chthamalus and/or Tetraclita Pomatoleios short algal turf Octomeris and/or Mytilus Pomatoleios Gelidium Coohlear mosaic Hypnea Sublittoral Zone Fringe lithothamnia, brown or red algae, or coral, or ascidians corallines, C. maschalocarpum C. elongatum Pyura Phylloapora Ecklonia Pyura Phylloapora Ecklonia Caulerpa, Plocamium Pyura Ecklonia Lessonia Ecklonia Ecklonia reference to basic zonation concepts. From Gislén's account it is clear that the central Japanese coastline displays a number of physical features closely resembling those in the Hauraki Gulf, whereas the Californian coast is in sharp contrast both regarding physical factors of the environment and littoral zonation. The Japanese coast, as at Sagami Bay, will be discussed first. The much incised coastline of Central Japan is composed of loose volcanic tuffs and sandstones favourable to attack by rock borers. Sea temperatures have a lower average limit, like those in the Hauraki Gulf, of about 13° C. A summer average maximum of 27° C. which is up to 5° C. above normal for the latitude, is caused by the northward-flowing Kuro Shiwo current. Colder, northerly water flows south in winter (Gislén, 1943, p. 26). Thus, on Stephenson's definition, the coast is a warm-temperate one. Summer rainfall is heavy, and winds gentle northerlies, although waves result from typhoons to the south. Earthquake damage in the littoral has caused silting up of many areas which are no longer colonised by organisms preferring clear water. Finally, the great diversity of species (but with a poor crop production in comparison with California), surprising in view of the environmental conditions, is attributed to the uninterrupted connection of Japan with tropical waters by currents for a considerable space of geological time. Gislén recognises three distinct critical levels: Average Higher High Spring Tide, Mean Sea Level, and Average Lower Low Spring Tide. From Gislén's Figure 6 (1943) the present writer has attempted in Table IX to deduce the probable basic vertical zonation sequences under conditions of shelter and exposure, dominants having been placed in their approximate positions with relation to the subdivisions of the littoral now generally recognised. The exposed coast sequence seems quite straightforward, with barnacles in the supralittoral zone and fringe. But their replacement by lithothamma high up in the midlittoral is unique, if the latter occur in sufficient quantity to partake in the basic zonation. It may be that the vertical distribution as indicated by Gislén in his Figure 6 is no guide to their degree of dominance at any level. In both exposed and sheltered situations the apparent paucity or absence of barnacles in the upper midlittoral of Sagami Bay is significant. Corallina, as on the New

South Wales coast, belongs to the exposed sequence. Heliocidaris, an echinoid, appears to be the sole dominant in the sublittoral fringe under severe wave exposure. The absence of large brown algae therefore would most likely be correlated with the difficulty of establishment of sporelings in silted-up areas. Zostera and Halophila on the other hand are evidently widespread. It is by no means certain that an accurate picture of zonation on a sheltered coast of Central Japan has been given in column 3 of Table XI. Monostroma for instance may not be sufficiently long-lived to contribute to the basic zonation. By comparison, a transient Monostroma parvum community appears at high levels in sheltered waters of the Hauraki Gulf in winter or spring (cf. Carnahan, 1952, p. 38). Batillaria, a shelled molluse resembling Zeacumantus in New Zealand, could possibly replace the littorinids so prevalent elsewhere about these levels. Zeacumantus, however, is restricted at high levels in the Hauraki Gulf to tide pools. About M.S.L. a serpulid community might well be the ecological equivalent of Pomatoceros, Galeolaria and Pomatolcios in the Southern Hemisphere. Sargassum thunbergi is notable for its occurrence almost up to M.S..L in Sagami Bay. Hauraki Gulf members of this genus are not to be found on exposed rock Table XI. Relationship of Warm-Temperate Zonation in the Hauraki Gulf to that in Comparable Regions of the Northern Hemisphere New Zealand: Hauraki Gulf Central Japan: Sagami Bay Atlantic North America: Bkaufort Marineland Supralittoral Fringe Zone after Gislen, 1943. after T.A. and A. Stephenson, 1952. sheltered exposed sheltered exposed sheltered exposed grey and yellow zone Melaraphe Balanus Tetraclita Melaraphe black zone black zone Monostroma? Balanus Ostrea? black zone black zone Midlittoral Zone C. columna C. brunnea Batillaria? Balanus black zone yellow zone. Volsella C. columna Cladophora- lithothamnia? Chthamalus Chthamalus Apophloea E. plicatus Polysiphonia Tetraclita E. plicatus C. columna Serpulid Saxostrea Ostrea Siphonaria lithothamnia Sargassum Chondrus-Gigartina Modiolus Gigartina Porphyra Ostrea Mytilus Pomatoceros short algal turf Turbinaria Chthamalus Corallina Muddy Zone Mytilus Hormosira Corallina Xiphophora Mytilus Ulva algel zone Encrusting corallines Cp. elongatum Laurencia Heliocidaris? mixed algae Gracilaria Sublittoral Zone Fringe Cp. maschalocarpum Ecklonia Lessonia Amphiroa above the level of the coralline turf. Dommance of the red algae Laurencia and Amphiroa is a further point of contrast. Halophila and Zostera are probably not basic zone formers on rocky coasts. From the above it seems that organisation of littoral community-complexes in Central Japan may differ in several respects from that in the II auraki Gulf. The most notable similarities between the two regions appear to be:

(1) the presence of rock borers in soft sandstone either below the surface or under overhangs; (2) occurrence of a serpulid community about half tide mark in sheltered habitats; (3) predominance of lithothamnia and Gigartina in the midlittoral where wave action is strong. Turning now to the Atlantic coast of North America, it is surprising to discover from the graphic descriptions of T. A. and A. Stephenson (1952) that the majority of littoral zones in warm-temperate Marineland and Beaufort have direct counterparts in north-eastern New Zealand. Beaufort, the most northerly station dealt with in that survey, has an average inshore sea temperature range of 12° to 26° C. Marineland, slightly warmer, varies from about 15.5° to 27° C. (T. A. and A. Stephesnon, loc. cit., Fig. 8). Rocky surfaces at Beaufort, composed entirely of artificial breakwaters made up of rough granite and mica schist blocks, support a sheltered coast community complex astonishingly similar in its ecological equivalents to a normal sheltered sequence inside the Hauraki Gulf. Habitat conditions similar in both regions include shallow water, which tends to be more turbid on lower rocks, and an abundance of shifting sand. With regard to the littoral biota, both regions are characterized by a black zone in the supralittoral fringe where Calothrix and Entophysalis abound, and in the midlittoral by barnacle, oyster, and what the Stephensons have termed muddy zones. Although the Hauraki Gulf has not been discussed under the subheading of “muddy zone” many localities in the region are silted up to varying degrees in the lower midlittoral, and in some cases Corallina is eliminated, Hormosira having larger thalli than on cleaner coasts (cf. Fig. 7). Mytilus* The species are not the same in this case., dominant with Ulva in the muddy zone at Beaufort, can exist in New Zealand in relatively turbid, even polluted, Gulf waters (e.g., M. canaliculus at Bastion Reef) (Plate 1, Fig. 1). Ulva lactuca, however, is a denizen of clear water locally. The oyster zone at Beaufort differs from that in the Hauraki Gulf in the prevalence of a Porphyra species (P. leucosticta). At the same time it appears from the Stephensons' Plate 6 that the area of rock covered by oyster shells is not generally speaking as great as that here in sheltered Gulf waters, where competition on an overcrowded rock surface may result in shells growing one upon another. Further, Mytilus exustus of Beaufort is more like the local Volsella in size of shell and vertical range, whereas Modiolus demissus, a typical estuarine inhabitant, is much larger. In the Gulf, too, growth of Enteromorpha in profusion on firm rock is apparently higher up in the midlittoral than its counterpart at Beaufort. One could compare the lower littoral green sward on the smooth, rounded Little Barrier boulders, were it not for the fact that these are washed by waters almost entirely free from sediment. The exposed, coquina rock beaten by oceanic waves at Marineland has been subdivided by the Stephensons into black, yellow and algal zones, within the broader supra-, mid- and sub-littoral boundaries. This coast shows a certain resemblance in general topography to a Waitemata Sandstone shore in that it possesses a prominent high water platform, a wide, bare, rocky or sandy stretch in the centre of the midlittoral, and a gentle slope into a shallow sublittoral. Shifting sand is an adverse factor in both regions, but the Marineland shores

suffer more profoundly from hot sun in summer and lethal winter frosts. Moreover, wave action is consistently stronger than that affecting the more protected sandstone shores inside the Hauraki Gulf. Points of resemblance between the Gulf and Marineland are seen particularly in the black zone, where Calothrix scopulorum and Entophysalis deusta are common species. (Symploca laeteviridis usually occurs below M.T.L. in the Hauraki Gulf.) A sparse barnacle population is confined to vertical faces in the mainly bare midlittoral, together with patches of Enteromorpha (but not Ulva in the Gulf) and a lower littoral carpet of short Rhodophyceae. Gracilaria, the chief sublittoral fringe dominant at Marineland, is an estuarine genus in the Hauraki Gulf. Large brown algae represented here by Carpophyllum and Ecklonia are conspicuous by their absence at Marineland, and even at Beaufort are poorly represented by Sargassum filipendula. Paucity in number of common species recorded at Marineland (37 compared with 105 at Beaufort) is supposedly related to the harsh combination of habitat factors. At Charleston, intermediate geographically between Beaufort and Marineland, still fewer species (34) are present—a fact due in large measure to extreme harbour pollution. Since the inner Auckland Harbour was not investigated in the present survey, comparable figures cannot be given; but in 1947–48, 93 algae and 52 animals were recorded from Narrow Neck (Dellow, unpub.), a sandstone area of moderate shelter suffering from intermittent deposition of silt and sand, plus a certain amount of organic pollution. General Summary and Conclusions While the survey of the Hauraki Gulf littoral region described in this work makes no pretence at being complete, it serves to indicate the major features of vertical and horizontal zonation in these waters. From it, the Hauraki Gulf littoral biota emerges as a predominantly warm temperate population, probably affected by a southward-penetrating arm of the Notonectian Current, and not subject to fierce wave action except during relatively infrequent north-easterly gales from the Pacific Ocean. The coastline is deeply indented, and includes a number of larger and smaller islands. Interesting comparisons can be made between west and east coasts of Coromandel Peninsula and Great Barrier Island, especially regarding the biological response to increased wave action. With increase in shelter, on the other hand, the influence of sand and mud is an important factor in governing the type of community complex; and the effects of harbour pollution cannot be ignored. (1) Thirty-four stations in the Hauraki Gulf were investigated: stations 1–2 in the Firth of Thames; stations 3–12 on the East Coast mainland; stations 13–25 about the islands of Kawau, Rangitoto, The Noises, Waiheke Tarakihi, Horuhoru and Hauturu; stations 26–30 round Coromandel Peninsula; and stations 31–34 on Great Barrier Island. (2) In Part I geological, climatic and hydrographic factors are discussed. Major rock types present are Mesozoic greywackes, Tertiary sandstones and andesitic breccias. Prevailing westerly winds affect the Gulf, blowing offshore on the mainland east coast, and onshore on the western coasts of Coromandel and Great Barrier. Easterly gales are severe, but comparatively rare, and more common in winter (June to September). Rainfall is heavier in winter, but rarely exceeds 50 inches per annum. Despite a high average relative humidity, fogs are infrequent, being confined to occasional still winter mornings.

Air temperatures show an average annual range of 3–27° C., and a maximal range of 0–32° C. In Hauraki Gulf waters several miles offshore, sea surface temperatures vary from 15 to 20.6° C. on the average, but inshore records in shallow water indicate a range of about 12° to 23.5° C. After rounding the north of New Zealand, the Notonectian Current is presumed to flow in a southerly direction past the Hauraki Gulf towards East Cape. It is probable that this current influences the tidal stream outside the Gulf, the behaviour of which is not fully understood. The tidal stream inside the Gulf sets to the south with a flooding tide and northward during ebb. Outside the Gulf on the open coast the situation is apparently reversed. Tides are semi-diurnal, the ranges varying at extreme springs from about 8 to 12 feet. Lowest spring tide occurs during mid-afternoon. Other hydrographical factors discussed include salinity, pH, oxygen concentration, pollution and turbidity. Presumably owing to the winter rainfall maximum and hence greater run-off from the high ranges of the Coromandel Peninsula plus the numerous streams and rivers flowing into the Gulf, salinities are lowest in winter. Extreme records indicate a range of 34.27 to 35.55%. pH of seawater in Auckland Harbour varies from 8.25 to 8.37. Supersaturation of oxygen occurs in tide pools where photosynthesis is active among the algal populations. Pollution results in certain areas from 7 different sewage outflows. Judging from high coliform counts, it is suspected that Rangitoto, as well as beaches as far north as Milford and east to St. Heliers in the outer Auckland Harbour are liable to be polluted. The extent of this influence on intertidal populations is not known. However, it has a secondary effect in increasing the turbidity of the surrounding water, and is likely to prevent growth of stenophotic, open coast species. (3) Guiler's (1949) formula to indicate the degree of wave action on a particular coast has been applied to the 34 stations examined in the Hauraki Gulf. (4) In Part II a brief discussion on terminology is given, followed by an account of the communities recognised. Twenty-nine permanent and 11 seasonal biotic communities are recorded. A list has been compiled of algae and other common littoral plants and animals encountered, and records made of the ecological status of each at the 34 stations examined (Appendix I).* Dried and preserved specimens have been deposited in the herbarium of the Dominion Museum, Wellington. (5) Part III comprises, first, a discussion of horizontal and vertical zonation in the Hauraki Gulf, in comparison with that recorded from Piha on the Auckland west coast and the Poor Knights, a group of oceanic islands off the east coast to the north of the Gulf. (6) Geographic relationships of the dominant species and communities are then reviewed. On the basis of Stephenson's (1947) definitions of temperature boundaries, it is suggested that the Gulf flora and fauna should be classed as warm temperate. The main categories represented include: (a) endemic species confined to the north of New Zealand; (b) endemic species ranging throughout New Zealand; (c) non-endemic species confined to northern New Zealand; (d) non-endmeic species occurring throughout New Zealand; (e) non-endemic species occurring mainly in the south of New Zealand;

(f) cosmopolitan species; (g) winter- and summer-seasonal species. (7) In a comparison between the total number of algae recorded from the Hauraki Gulf and those listed by Womersley (1950) from Kangaroo Island, South Australia, it is seen that the latter has almost double the number of species of Phaeophyceae and Rhodophyceae. The reason for the discrepancy is obscure, but may be due at least in part to the more turbid state of waters in many parts of the Gulf. (8) Finally, the sequence of basic zone formers are compared and contrasted with other reports from similar warm temperate coasts in both Northern and Southern Hemispheres. Acknowledgments To all those people who have helped in the preparation of this work the writer expresses her sincere thanks. In particular she is deeply indebted to her husband, Mr. R. M. Cassie, for valuable assistance throughout the compilation, to Professor V. J. Chapman, under whose direction the survey was carried out, and to the Research Grants Committee of the University of New Zealand for their generous financial grant. The assistance of the following is also gratefully acknowledged: Miss S. D. Baker, Dr. M. A. F. Barnett (Director of Meteorological Services), Dr. R. N. Brothers, Mr. J. A. Carnahan, Dr. R. C. Cooper, Mr. and Mrs. R. Cooper, Mr. A. B. Cribb, Miss R. F. De Berg, Mr. R. K. Dell, Mr. K. J. Dellow, Dr. P. Dohrn, Captain A Duthie, Mme. G. Feldmann, Mrs. D. Freed, Mr. A. S. Fuller, Mr. E. W. Gilliver, Mr. R. Haxell, Mr. D. F. Hobbs, the late Mr. W. M. Jones, Mr. and Mrs. J. Kiernan, Mr. G. A. Knox, Mr. A. Lee, Mr. V. W. Lindauer, Mr. R. Lloyd, Miss M. Lokes, Dr. L. H. Millener, Miss L. B. Moore, Professor L. Newton, Mr. L. Oldham, Professor G. F. Papenfuss, Mr. and Mrs. C. Parkin, Dr. E. G. Pringsheim, Mr. G. F. Russell, Misses I. and J. Shakespeare, Mr. W. C. Smith (Secretary of Marine), Mr. P. A. S. Stein, Professor T. A. Stephenson, Mrs. P. A. Williamson, Dr. H. B. S. Womersley, and finally the members of A.u.c. Field Club who helped the writer so enthusiastically during 1949 and 1950.

Appendix I. Species d = dominant; a = abundant; f = frequent; o = occasional; r = rare; l = local; x = drift only; † = confined to pools. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 I. Algae Cyanophyta. Glorocapsa alpicola (Lyng.) Born. T Aphanocapsa marina Hansg. o Dermocarpa prasina (Ref.) Born. et Thur. l l r l o l O Entophysalis deusta (Menegh.) Dr. & Daily a ld a f f ld f a o f E. conferta (Kuetz.) Dr. & Daily r Oscillatoria nigroviridis Thwaites o la o ld l o o O. laetevirens Crouan r Phormidium corium (Ag.) Gom. ld P. ambiguum Gom. ld Lyngbya maiuscula (Dill.) Harv. +la o o o +la lf f ld L. confervoides C. Ag. o +l +o +lf o +a o o L. semiplena (C. Ag.) J. Ag. f ld +l l Symploca laete-viridis Gom. ld o a Microcoleus acutissimus Gard. o o M. tenerrimus Gom. O

Nostoc commune Vaucher o l Hydrocoleus lyngbyaceus o Nodularia harveyana (Thur.) Thur. o la o o Anobaena variabilis Kuetz. o Calothrix scopulorum (Web. & Mohr) C.Ag. f d l d d r C. crustacea Thur. ld o l C. pilosa Harv. l C. parietina (Naeg.) Thur. o Rivularia custralis Harv. ld ld lf R. Polytis (Ag.) Born. Et Flah. ld la o Brachytrichia quoyl (Ag.) Born. Et Flah. a Isactis plana (Harv.) Thur. f a f a a o o o a f o r Asterocystis ornate (Ag.) Hamel l Chlorophyta Ulothrix flacca (Dill.) Thur. r r Monostroma lindaueri Chapman l M. crepidinum Farlow l M. parvum Chapman lf o r r l

Letterstedtia petiolata J. Ag. ld ld Ulva lactuca L. l a f a a a a a f Ulva latissina L. ld ld Enteromorpha flexuosa l Enteromorpha intestinalis (L.) Grev. Ld ld l E. compressa (L.) Grev. f. brevis Chapman l l E. compressa (L.) Grev. var. australiensis Chap. ld ld E. compressa (L.) Grev. f. subsimplex J. Ag. ld ld la ld o o? E. prolifera (Muell.) J. Ag. var. flexuosa Wulff. la E. bulbosa (Suhr.) J. Ag. o ld la ld E. nana (Som.) Bliding d ld E. nana var. minima Blid. ecad fastigiata Chap. o E. nana var. marginata (J. Ag.) Chap. o E. clathrata (Roth.) Ag. var. plumosa Kuetz. o E. procera Ahin. f. minuta Chap. ld a d l la o f a f E. procera Ahin. f. novae zelandiae Chap. d f a a la la lf l f f E. procera f. eramosa (Schiff.) Chap. Ms. ld

Prasiola crispa Men. o P. stipilata Suhr.? d Sporocladosis novae zelandiae Chap. f r l Protoderma marina Reinke r Chaetomorpha melargonum (W. and M.) Kuetz. r C. aerea (Dill.) Kuetz. f o l o f o o C. aurea Chap. o C. linum (Muell.) Kuetz. o o C. capillaris (Kuetz.) Börg. la C. litorea Cooke l Rhizoclonium riparium (Roth.) Harv. ld l o f o la f l d R. elongatum Chap. r R. implexum (Dill.) Kuetz. l ld l o o f r l R. hookeri Kuetz. o o f f f o f R. tortuosum (Dill.) Kuetz. r r o Hormiscia penicilliformis (Roth.) Fries. r Cladophora crinalis Harv. l r ld l d l r C. colensoi Harv. r r Cladophoropsis herpestica (Mont.) Kuetz. o o o f l o o o a Wittrockiella salina Chap. ld ld o l l Microdictyon mutabile Delow f o o ld f o o a o o ld

Vaucheria synandra Woron. r Derbesia novae zelandiae Chap. r r o a a r Bryopsis plumosa (Huds.) Ag. o ?r o r o r B. corticulans Gard. var. novae zelandiae Chap. l o l Caulerpa hypnoides (R. Br.) Ag. x x C. sedoides (R. Br.) Ag. f. novae zelandiae Chap. ld la la l o Codium adhaerens Ag. var. convolutum Dell. o f a f a f f a a f d d ld r o ld o a o f f ld C. cranwelliae Setch. ld C. gracile (Schmidt) Dell. x Phaeophyta Pylaiella novae zelandiae (Grun.) Setch. o a f a ld a f la f ld ld f o x Ectocarpus duchassaing-ianus Grunow? r o Ectocarpus sp. f a o f a E. indicus Sonder f la la o r o l E. confervoides (Roth.) Le Jolis l Herponema maculaeformis (J.Ag.) Laing l Hapalospongidion saxigenum Lindauer. o l d d o o o

S. tribuloides Men. r r Halopteris brachycarpa Sauv. (?) x Halopteris spicigera (Aresch.) Moore x o ld f Hulopteris hordacca (Harv.) Sauv. x Cutleria multifida (Smith) Grev. x Dictyota dichotoma (Huds.) Lmx. l r D. dichotoma var. intricata (Ag.) Grev. o lf r o o Dictyota ocellata J. Ag. o o r o l Glossophora la f o f o ld ld f d d f f Spatoglossum chapmanii Lindauer ld ld f subarticulata (Lmx.) Papenf. o o l r o o o o f Raljsia (Aresch.) J. Ag. d ld a a d f f a d d d d d d d Elachista australis J. Ag. la la Leathesia difformis (L.) Aresch. f a a f f a a a f o lf Myrioglora lindaurii Kylin. O ld ld Tinocladia novae-zelandiae Kylin. o r Splachnidium rugosum (L) Grev. l la f r o o f f o f f o r Sporochnus stylosus H. et H. x Perithaha capillaris J. Ag. x Carpomitra costata (Stackh.) Batt. x

Ilea fascid (Muell.) Fries o 1 la o o Scytosiphon lomentana (Lyngh.) J. Ag. ld lf ld 0 o Colpomenia sinnosa (Roth.) Derb et Sol. f a a f a f o a f f o o Scytothamnus H. et H. f ld o o f f f o r ld ld o o Lessonia variegata J. Ag. d x d Echlonia radiata (C. Ag.) J. Ag. d d d d ld d d d d d ld d d ld ld ld ld ld ld E. radiata var. richardiana J. Ag. f a d x ld d Xiphophora chondrophylla (R. Br.) Mont. var. minus J. Ag. d f d a d d ld d d d d d d ld d Landsburgia quercifolia H. et H. x Cystophora retroflexa (Labill.) J. Ag. o o C. torulosa (R. Br.) Dec'ne f ld ld a a o d f a ld d f o ld Sargassum sinclarii H. et H. o f f f o o o ld S. undulatum J. Ag. f f S. spinuligerum Sond. a ld f Corpophyllum elongatum (Dickre) A. & E. S. Gepp. d ld d ld C. flexuosum (Esper.) Grev. f ld ld a ld ld f f C. maschalocarpum (Turn.) Grev. d d d d d d d d d d d d d ld d d d d d d d f ld d d d d d d C. plumosum (A. Rich.) J. Ag. f d d la d ld a ld d ld f d d ld ld f ld C. plumosum var. capillifolium A. Rich. f f f f f f

Hormosira banksii (Turn.) Dec'ne d d ld d f ld ld H. banksu var. sieberi Harv. d ld d d a ld ld lf ld ld d ld ld a lf anomala Bail. et Harv. a a lf antarctica (Cham.) Hariot ld Note: Nemacystus novae-zelandiae Kylin, collected by L. M. Cranwell at Squadron Bay Reef, Waiheke, in 1933, was not found in this survey. Phodophyta Comotrichum elegans (Chauv.) Zan. r r Erythrotrichia hunterae Gard. r r l r Bangia fusco-purpurea (Dillw.) Lyngb. la lf o B. vermicularis Harv. ld columbina Mont. f o f o f l P. umbilicalis (L.) J. Ag. var. zelandiae ld o l o P. subtumens J. Ag. ?r Acrochuetium sp. lf Rhodochorton Rothi (Turt.) Naegeli? ld Asparaqopsis armata Harv. l o f Falhenbergia infolanosa r

Nemalion sp. l Liagora harveyana? Zeh. f ld lf o l Helminthocladia australis Harv. ld ld Chaetangium corneum J. Ag.? a d scinuroides J. Ag. x o Caulacanthus spinellus (H. et H.) Kuetz. a f ld a a d ld d d f a ld a f Gelidium caulacanthcum J. Ag. f a ld ld f f ld d o f f ld f d lf ld G. pusillum le Jol. Ld o o d ld ld f la o la f f f ld d lf a f ld G. corneum (Huds.) Lmx. G. crinale (Turn.) Lmx. l ld Pterocladia lucida (R. Br.) J. Ag. o l f f lf f f ld d P. lucida var. sublittoralis ld P. capillacea (Gmel.) Born. o o ld f ld ld o f o o f f Aeodes nitidissima J. Ag. f Cryptonemia latissima J. Ag. x Pachymenia himantophora J. Ag. d Grateloupia polymopha (H. et H.) Lg. r Callophyllis decumbens J. Ag. o Rhizopogonia asperata (H. et H.) Kylin. r l r r r Cruoria sp. l Hildenbrandtia crouanii J. Ag. ld o ld la o la ?o Peyssonelia rubra (Grev.) J. Ag. f ?o f ?o ?f ?f

P. harveyana? f Lithothamnion spp. +ld a ld la ld d d d ld d ld Lithophyllum spp. +ld f ld la d d d o ld d ld Melobesia spp. d a d d d a d ld d d d d d a d d ld Cheilosporium elegans H. et H. Aresch. lf C. corymbosum? r l +l +o Corallina officinalis L. d D d d d d ld d d d d f d d f ld d ld d d l l d d ld d ld C. cuvieri Lmx. o Jania rubens? (L.) Lmx. o o f f f J. micrarthrodia Lmx. o o Apophloea Harv. ld ld ld d d ld ld f f d d d Nemastoma oligarthra (J. Ag.) Kylln. a o d d o lf N. feredayi H. et H. +l? Schizymenia novae zelandiae J. Ag. o l o a +o +l o o Catenella nipae Zan. d ld C. fusiformis (J. Ag.) Skottsberg. r r Craspedocarpus erosus (Harv.) Schmitz. r Hypnea musciformis (Wulf.) Lmx. x Plocamium abnorme (Harv.) f lf P. angustum J. Ag. o x f f x Phacelocarpus labillardieri (Mert.) J. Ag. r o o f o s f x

Sarcodia montagneana J. Ag. ld Curdiaea engelhartii (J. Ag.) C. crateriformis (J. Ag.) Kylin. x Cracilaria secundata Harv. f. pseudo-flagellifera Val. May o la ld Melanthalia abscissa (Turn.) H. et H. l o f o f f f +o Tylotus proliferus (Harv.) Kylin. r r x Gymnogongrus nodiferus (H. et H.) J. Ag. ld Stenogramma interrupta (Ag.) Mont. x Gigartina alveata J. Ag. ld ld d G. atropurpurea (J. Ag.) +l f o G. chapmanii H. et H. o r d G. cranwellae Laing. sp. ined. a a G. macrocarpa J. Ag. la f f G. laingii Lindr. sp. ined. d d f l o Lomentaria umbellata H. et H. f +f r o L. caespitosa (Harv.) comb. nov.? l r Champia novae zelandiae H. et H. var. dolichopoda J. Ag. o o f a a f C. laingii Lindauer a +la Rhodymenia leptophylla J. Ag. +o +o +o +o +o +f f R. palmetta? r

Antithamnion adnatum J. Ag. r r +o A. applicitum (H. et H.) J. Ag. +r +r Centroceras clavulatum (C. Ag.) Mont. f o f o a o f f o Ceramium apiculatum J. Ag. o +o o r f +l o r +o o +o C. uncinatum H. et H. r C. gracillimum Griff. et Harv. var. byssoideum (Harv.) G. mazoyer l o o r a Microcladia novae zelandiae J. Ag. 25 Ptilothamnion pectinatum (Mont.) Lg. r la antarctica (H. et H.) l +o r Pandorea traversii J. Ag. +r +r o +o +o +o Pleonosporium hirtum (H. et H.) Lg. a +r +o r o a r o r o x Monospora griffithsioides (Sonder) De Toni r Callithamnion colensoi H. et H. ?r ?r r +r Caloglossa leprieurii (Mont.) J. Ag. lf l d ?o Apoglossum montagneanum (Harv.) J. Ag. x Delesseria sp. Nov. r r Myriogramme gattyana (J. Ag.) Kylin. l M. denticulata Kylin. +o +l +o a o

Abrotela suborbicularis (Harv.) J. Ag. lf o o lf r r r f Acrosorium decumbens (J. Ag.) Kylin. o r o r A. uncinatum (Turn.) Kylin. ?r r Hymenena berggreniana (J. Ag.) Kylin. r aphanocladia delicatula (H. et H.) Falk. r la r Lophurella casspitosa (H. et H.) Falk. r o ld a metamorphe colensoi (H. et H.) Falk. r r +o r Pleurostichidium falkenbergii Heydr. o la f a Polysiphonia isogona H. et H. l f P. variabilis H. et H. r f a a f Polysiphonia rudis? r a Polysiphonia sp. o +r +o f l r f Bostrychia arbuscula H. et H. ld l l f la la d ld ld la o ld ld ld f ld B. mixta H. et H. ld ld l l la f la d ld la a o B. similis Rbd. la ?l B. harveyi Mont. la la Cladhymenia oblongifolia H. et H. o

Lourencia botrychioides Harv. f f f o o f o f f +f L. distichophylla J. Ag. o o l l l o o f L. (C. Ag.) J. Ag. o o +o f f o f ld r l o o f o o Symphyocladia marchantioides H. et H. Falk. o +o r r +o Dipterosiphonia heteroclada (J. Ag.) Falk. r lf o r o r Herposiphonia sp. r r Lophosiphonia macra (H. et H.) Falk. lf Euzoniella incisa (J. Ag.) Falk. f o f f f o f E. bipartita (H. et H.) Falk. r +r E. ovalifolia (H. et H.) Falk. +1 Lenormandia coronata Lindr. et Setch. +r +r Vidalia colensoi (H. et H.) J. Ag. +l r +l la ld Heterosiphonia subtilis Lindauer Ms. r r o o +l r H. Lindr. Ms. l

II. Lichens Lichina pygmaea Ag. ld d ld ld ld ld ld d d d ld d ld d l ld d d ld ld ld Verrucaria maura Wahl. d f f f o ld Xanthoria parietina Th. Fr. d d f ld d a ld Ramalina lelodea Nyl. a f la f ld ld d Physcia sp. d d a d d f a Parmelia sp. d d d d f a Caloplaca sp.? o la o l o l o r Cladina sp. D III. Angiosperms Parietaria debilis Forst. f. Prodr. la Mesembryanthemum australe Soland. f a f o o Coprosma repens A. Rich. o d Salicornia australis Soland. o d a o a d ld o Metrosideros excelsa Sol. et Gaertn. d a f d o o Stipa teretifolia Steud. f d Avicennia offioinalls L. ld d ld lf vostera marina Hook. f. d d ld ld

IV. Animals Pomatoceros coeruleus (Schmarda) d d ld d o f ld d ld o d o d o d Sabellaria kaiparaensis Augener d ld la a Saxostrea glomerata (Gould) d o d d ld d d f d d d ld d ld d d ld d r o d Mytilus canaliculus Martyn d ld ld ld d d ld Chione stutchburyi (Gray) ld Anchomasa simills (Gray) ld ld Pholadidea tridens (Gray) ld ld P. spathulata (Sowerby) ld ld Lunella smaragda (Martyn) f f f a a f f f a a f Actinia tenebrosa Farquhar f Nerita melanotragus (Smith) f d a a d Cellana spp. a a f f a f a Melaraphe spp. Ld d d d d d d d d d ld d d d d d d Volsella neozelanicus Iredale d d ld d d d ld ld ld ld Mitella spinosa Quoy & Gaimard Elminius modestus Darwind ld d ld d ld d ld ld d d d ld E. plicatus Gray d ld d o f d d d ld ld ld ld f ld Chamaesipho columna Spengler d d ld d d a d d d d d d d d d d la d d d C. brunnea Moore ld f la d d ld ld d d d d d d ld d D

Seasonal Dominants Winter-Spring Monostroma parvum. Northern New Zealand, East Coast (Chapman Ms.). Scytosiphon lomentaria. New Zealand; Stewart Island; Chatham Island; cosmopolitan (Lindauer, 1947). Ilea fascia. New Zealand; Chatham Islands; almost cosmopolitan (Lindauer, 1947). Porphyra columbina. New Zealand? (Laing, 1926). Spring-Summer Tinocladia novae-zelandiae. New Zealand; Stewart Island; endemic (Lindauer, 1947). Myriogloia lindauerii. New Zealand; endemic (Lindauer, 1947). Colpomenia sinuosa. Cosmopolitan (Lindauer, 1947). Leathesia difformis. Cosmopolitan (Lindauer, 1947). Nemastoma oligarthra. New Zealand; endemic (Laing, 1926, as Catenella oligarthra). Whatipu, Mayor Island; Great Barrier; Taranga (C. B. and J. Trevarthen; personal communication). Coromandel Peninsula to Bay of Islands (Laing, 1939); Wellington (Moore; personal communication). Summer-Autumn Splachnidium rugosum. New Zealand; Stewart Island; Chatham Islands; South Africa; St. Pauls Island; East Indies; New Amsterdam; Juan Fernandez; San Felix; Australia, Tasmania (Lindauer, 1947). Liagora harveyana. Northern New Zealand; South Australia; North Tasmania (Lucas, 1947). Helminthocladia australis. Northern New Zealand; Western Australia (Lucas, 1947). Bibliography Ambler, M. P. and Chapman, V. J., 1950. A quantitative study of some factors affecting tide pools. Trans. Roy. Soc. N.Z., Vol. 78, pp. 394–409, Figs. 1–9. Babtrum, J. A., 1921. Notes on the Geology of Great Barrier Island, New Zealand. Trans. N.Z. Inst., Vol. 53, pp. 115–127, Pls. XXII, XXVII. —— and Turner, F. J., 1929. The geology of the Takapuna-Silverdale district, Waitemata County. Trans. N.Z. Inst., Vol. 59, pp. 864–902. Bassindale, R., 1943. Studies on the biology of the Bristol Channel. XI. The physical environment and the intertidal fauna of the southern shores of the Bristol Channel and the Severn Estuary. Journ. Ecol. Vol. 31, pp. 1–29. Bennett, I. and Pope, E. C., 1953. Intertidal zonation of the exposed rocky shores of Victoria, together with a rearrangement of the biogeographical provinces of temperate Australian shores. Austral. Journ. Mar. and Freshw. Res., Vol. 4, pp. 105–159, Pls. I-VI, Figs. 1–5. Beveridge, W. A. and Chapman, V. J., 1950. The zonation of marine algae at Piha, in relation to the tidal factor. Pacif. Sci., Vol. 4, pp. 188–201, Figs. 1–14. Bishop, M. W. H., 1947. Establishment of an immigrant barnacle in British coastal waters Nature, Vol. 159, pp. 501–502, Fig. 1. Brewin, B. I., 1951. Ascidians of New Zealand. Part VI: Ascidians of the Hauraki Gulf. Part II. Trans. Roy. Soc. N.Z., Vol. 79, pp. 104–113. Figs. 1–8.

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Knowles, M. C., 1913. The maritime and marine lichens of Howth Head. Ireland. Sci. Proc. Roy, Dublin Soc., Vol. 14. pp. 70–143, Pls. I-VII. Knox, G. A., 1953. The intertidal ecology of Taylor's Mistake, Banks Peninsula. Trans. Roy. Soc. N.Z. Vol. 81, pp. 189–220, Pls. 15–16, Figs. 1–8. —— Unpub. Studies on a serpulid Pomatoceros coeruleus Schmarda. M.Sc. thesis, 1949. in Canterbury University College library. Kulka, R. Unpub, Hydroids of the Auckland region. In “Tane”, Journ. Auck. Univ. College Field Club, 1950. Laing, R. M., 1920. A reference list of New Zealand marine algae. Trans. N.Z. Inst., Vol. 57, pp. 126–185. —— 1927. The external distribution of the New Zealand marine algae and notes on some algological problems. Trans. N.Z. Inst., Vol. 58, pp. 189–201. —— 1939. New Zealand Seaweeds, reference list No. II. The Rhodophyceae—Part A. Trans. Roy. Soc. N.Z., Vol. 69, p. 134. Lewis, J. R., 1953. The ecology of rocky shores round Anglesey. Proc. Zool. Soc. Lond., Vol. 123. pp. 481–549, Pls. 1–4. Figs. 1–15. Lindauer, V. W., 1947. An annotated list of the brown seaweeds, Phneophyceae, of New Zealand. Trans. Roy. Soc. N.Z., Vol. 76, pp. 542–566. —— 1949. Notes on marine algae of New Zealand I. Pacif. Sci., Vol. 3, pp. 340–352. Figs. 1–8. Lucas. A. H. S., 1947. The Seaweeds of South Australia. Part II. The Red Seaweeds, pp. 1–458. Figs. 1–202, Adelaide. Marine Department Records, 1949–1952. Wellington. Mirams, R. V. Unpub. A study of some factors concerned in the natural regeneration of the kauri (Agathis australis). Ph.D. thesis, in Auckland University College library. Moore, H. B., 1935. The biology of Balanus balanoides, IV. Relation to environmental factors. Journ. Mar. Biol. Ass., Vol. 20, pp. 279–307. Moore, L. B., 1944a. New Zealand seaweed for agar manufacture. N.Z. Journ Sci. and Tech., Vol. 25, pp. 183–209. Figs. 1–16. —— 1944b, Some intertidal sessile barnacles of New Zealand. Trans. Roy. Soc. N.Z., Vol. 73, pp. 315–334, Pl. 46, Figs. 1–2. —— 1948. “Our Living Environment”—Seaweeds. Post Primary Schools Bulletin. Vol. 2. No. 13. Wellington. —— 1949. The marine algal provinces of New Zealand. Trans. Roy. Soc. N.Z., Vol. 77. Part 5, pp. 187–189. —— 1950. A “loose-lying” form of the brown alga Hormosira. Trans. Roy. Soc. N.Z., Vol. 78, pp. 48–53, Pls. 8–9. —— 1953. Some distribution problems from brown algae of the genus Halopteris. Proc. Seventh Pacif. Sci. Congress, Vol. 5, pp. 13–18, Figs. 1–10. Newton, L., 1931. A handbook of the British seaweeds. pp. 1–478, Figs. 1–270. London. —— and Crtbb, A. B., 1951. Some aspects of algal ecology in Britain and Australia. Research, Vol. 4, pp. 449–455, Figs. 1–5. New Zealand Pilot, 1946. Eleventh edition, reprinted 1948. pp. 1–447. London. Nicol, E. A. T., 1935. The ecology of a saltmarsh. Journ. Mar. Biol. Ass., Vol. 22, pp. 203–261, Figs. 1–17. Oliver, W. R. B., 1923. Marine littoral plant and animal communities in New Zealand. Trans. N.Z. Inst., Vol. 54, pp. 496–545, Pls. 42–50, Figs. 1–9. Powell, A. W. B., 1937. The shellfish of New Zealand, pp. 1–100, Figs. 1–18. Auckland. —— 1947. Native animals of New Zealand. Auckland. Rigg, G. B. and Miller, R. G., 1949. Intertidal plant and animal zonation in the vicinity of Neah Bay, Washington. Proc. Calif. Acad. Sci., Vol. 26, pp. 323–351, Figs. 1–8. Sandison, E. E., 1950. The appearance of Elminius modestus Darwin in South Africa. Nature, Vol. 165, pp. 79–80. Searle, E. J., 1948. Geology of the Auckland district. Education Department, Auckland, pp. 1–40, Figs. 1–24. Setchell, W. A., 1915. The law of temperature connected with the distribution of marine algae. Ann. Missouri Bot. Gard., Vol. 11. pp. 287–305. —— 1917. Geographic distribution of the marine algae. Science, N.S., Vol. 45, pp. 197–204. —— 1920. The temperature interval in the geographic distribution of marine algae. Science, N.S., Vol. 52. pp. 187–190. —— 1920. Stenothermy and zone invasion. The Amer. Nat., Vol. 54, pp. 385–397.

Skottsberg, C., 1941. Communities of marine algae in subantarctic and antarctic waters. Kungl. Svensk, Vedensk, Handl., Bd. 19, pp. 1–92, Pls. 1–3, Figs. 1–7. Stephenson, T. A., 1939. The constitution of the intertidal fauna and flora of South Africa. Part I. Linn. Soc. Lond., Journ. Zool., Vol. 40. p. 487–536, Pls. 1–17. —— 1944. Part II. Ann. Natal Mus., Vol. 10, pp. 261–358, Pls. 12–14, Figs. 1–13. —— 1947. Part III. Ann. Natal Mus., Vol. 11, pp. 208–324, Pls. 15–16, Figs. 1–11. —— and Stephenson, Anne, 1949. The universal features of zonation between tide marks on rocky coasts. Journ. Ecol., Vol. 37, pp. 289–305, Pl. 8, Figs. 1–4. —— 1950. Life between tide marks in North America. I. The Florida Keys. Journ. Ecol., Vol. 38, pp. 354–402, Pls. 9–15, Figs. 1–10. —— 1952. II. Northern Florida and the Carolinas. Journ. Ecol., Vol. 40. pp. 1–49, Pls. 1–6, Figs. 1–9. Svederup, H. U., Johnson, M. W. and Fleming, R. H., 1942. The oceans, their physics, chemistry and general biology, pp. 1–1087, Figs. 1–265. New York. Trevarthen, C. B., 1953. The use of a zonation diagram in interdidal ecology. Science Record, Vol. 3, pp. 5–12. Figs. 1–3. —— Unpub. An introductory study of features of zonation at the Bay of Islands in relation to the effects of exposure to wave action. Wallace, G. M. and Newman, L. E. 1953a. Bacteriological survey of Auckland Harbours. I. Extent of sewage fields in Waitemata Harbour. N.Z. Journ. Sci. and Tech., Vol. 34, pp. 515–522, Figs. 1–8. —— and Newman, L. E. 1953b. II. Condition of beaches to the cast of Orakei sewer outfall, Waitemata Harbour. N.Z. Journ. Sci. and Tech., Vol. 35, pp. 225–238, Figs. 1–13. Williams, L. G., 1949. Marine algal ecology at Cape Lookout, North Carolina. Bull. Furman Univ., Vol. 31, pp. 1–21. Womersley, H. B. S., 1947. The marine algae of Kangaroo Island. I. A. general account of the algal ecology. Trans. Roy. Soc. S. Austral., Vol. 71, pp. 228–252, Pls. 9–13. —— 1948. II. The Pennington Bay region. Trans. Roy. Soc. S. Austral., Vol. 72. pp. 143–166, Pls. 10–15. —— 1950. III. List of species. I. Trans. Roy. Soc. S. Austral., Vol. 73, pp. 137–197, Figs. 1–2. —— and Edmonds, S. J., 1952. Marine coastal zonation in Southern Australia in relation to general schemes of classification. Journ. Ecol., Vol. 40, pp. 84–90. Fig. 1. Mrs. R. M. Cassie 51 Poole Crescent Wainui-o-mata.

Fig. 1.—An mosaic of Coverham district photographed at about 16,000ft. Topography Langes from 900ft to 3,500ft Scale and yard grid are only approximately correct River marked by solid lines traeks by dotted lines. and mam drainage divides by dash dot lines Note trench eaused In Recent faulting north and east of the words “Civer Stream.