The Migratory Trout (Salmo trutta L.) in New Zealand. I—The Introduction of Stocks.

Transactions of the Royal Society of New Zealand : Zoology, Volume 4, Issue 17, 31 July 1964, Page 209

The Migratory Trout (Salmo trutta L.) in New Zealand. I —The Introduction of Stocks.

D. Scott

By

Zoology Department, University of Otago. [Received by the Editor, September 16, 1963.]

Abstract

The status of the trout (Salmo trutta L.) in the coastal waters of New Zealand is considered. In addition to importations of brown trout from Tasmania, not less than 6 importations of sea trout ova were made by different bodies or individuals during the first decade of salmonid introduction. Young sea trout were released in four known localities and probably released in several more. Competent observers identified sea trout from 1874 to the end of the century. It is concluded that breeding populations of sea trout were established in the south-east of the South Island of New Zealand.

Introduction

The presence of trout ( Salmo trutta L.) in the coastal waters of New Zealand was noted shortly after the introduction of salmonids to the country (Arthur, 1878), and such populations still exist (Hobbs, 1948; Stokell, 1955). The origin and status of these trout is not, however, clear, and the many statements on this problem are not supported by any substantial body of evidence.

The views that have been expressed fall broadly into two classes. On the one hand are those whose attention was drawn to the occurrence of brown trout in coastal waters, and Arthur (1884) was among the first to record this fact. In commenting on the brown trout in Otago Harbour (Arthur, 1884, p. 499) he notes a tendency to resemble sea trout in certain details of colouration. Day (1887, p. 7, 145, 184) refers to Arthur’s papers and suggests that the brown trout in question are in the process of assuming the appearance and habits of sea trout. A number of workers in Europe followed this view, but it appears that they are quoting Day rather than Arthur. Galderwood (1908, p. 6) states that brown trout taken from England to New Zealand quickly acquired a migratory habit. Regan (1911, p. 56) states that river trout exported to New Zealand gave rise to an anadromous race. Lamond (1916, p. 24) quotes Galderwood, and agrees with Regan’s statement. This view is taken farthest by Vladykov (1934) who quotes Day (1887) and states:

“For example European brown trout, landlocked forms of Salmo trutta, transported to New Zealand change their habits and transform into typical anadromous S. trutta ”

Arthur’s original comments have thus become substantially altered by quotation.

On the other hand Nall (1930, p. 81), Menzies (1936, p. 61) and Tchernavin (1939) have pointed out that sea trout were taken from Britain to New Zealand. They all express the opinion that the populations of trout in the coastal waters of New Zealand are probably derived mainly from these importations of sea trout.

It is clear that several related problems are involved here. The presence of brown trout in estuaries and the sea does not constitute a real problem, since the presence of brown trout in the sea has been recorded from Europe (Calderwood, 1908; Nall, 1930; Menzies, 1936; and Skrochowska, 1959).

It is therefore to be expected that the brown trout in New Zealand would have a distribution extending through estuaries to coastal waters. A more important question is the extent to which brown trout in the sea come to resemble sea trout in appearance. The problems in New Zealand concern the fate of the introduced sea trout and their relation to present day migratory populations. Finally, the problem which is basic to all the others concerns the nature of the differences between brown trout and sea trout. A review by Trewavas (1953) shows the need to apply recent concepts in speciation to this question.

The present series of papers will attempt to examine these problems, and this paper will examine the evidence on the introduction and establishment of the sea trout in New Zealand.

Establishment in Tasmania

In order to determine the origin of some of the trout stocks in New Zealand, it is necessary to examine the introduction of trout to Tasmania. The first successful importation of fertilised ova was made by the Tasmanian Government, and the stocks that are of concern here are the brown trout and sea trout imported in the 1860’s.

Thames-Itchen brown trout stock

Although the history of introduction of this stock has been recorded, it is useful to include it here and to confirm the original sources of the ova.

An historical account is given by Seager (1889), and it was not until 1864 that a shipment in the clipper Norfolk reached Tasmania in good condition. The shipment had been organised by James A. Youl, and the ova were unpacked at the hatchery on the River Plenty on 21st April, 1864 (Salmon Commissioner’s Report, 1864). The bulk of the shipment contained Atlantic salmon ova (Salmo solar ) but brown trout were also included. The origin of the brown trout is recorded by a number of authors (Arthur, 1878; Nicols, 1882; Stokell, 1955) but no confirmation by the collectors of the ova is given. Youl (1864) states that in January, 1864, 2,700 trout ova arrived at the East India Docks where the Norfolk was lying, 1,200 being from Frank Buckland and 1,500 being from Francis Francis.

Buckland (1883, p. 317) refers to this shipment and states that the ova were taken from one pair of trout in a tributary of the River Itchen at Bishopstoke, Flampshire. Francis (1879) refers to his part in the shipment and states that the ova were taken from trout in the River Wey, Alton, Hampshire, and the River Wycombe, High Wycombe, Buckinghamshire. (These writers followed the customary usage of referring to brown trout as “trout” or “common trout”.) On the basis of these statements, it is proposed to refer to this stock as the ThamesItchen brown trout.

The subsequent establishment of this stock in Tasmania is well documented, and it may be noted here that 200—300 brown trout hatched from the Norfolk shipment. This lot alone was the basis of the brown trout stocks in Tasmania, and a shipment of 500 brown trout ova in 1866 gave only dead ova on arrival (Salmon Commissioner’s Report, 1866).

Tweed sea trout stock

Among other successful shipments, Youl supervised the collection and packing of ova in 1866. The clipper Lincolnshire left London on 20th January, 1866, with 10,000 sea trout ova, the ova arrived at the hatchery on 4th May and 1.000 sea trout hatched during this month (Salmon Commissioner’s Report, 1866). The origin of the sea trout ova is not given by the Commissioners, but Johnston (1883), a Tasmanian ichthyologist, gives a list of rivers of origin of the introduced salmonids and states that the sea trout came from the River Tweed, Scotland. This statement occurs also in the Report of the Royal Commission on the fisheries of Tasmania (1882). According to Nicols (1822, p. 40) the ova were taken by R. Ramsbottom of Clitheroe, Lancashire. Nicols had the assistance of Youl in obtaining material for his book, and it appears that Ramsbottom was responsible for collecting ova for all shipments organised by Youl. Ramsbottom (1854) had experience in the rearing of salmonids, and seems to have been aware of the extent of intra-specific variation in certain species.

The subsequent establishment of this stock is well documented. In the Salmon Commissioner’s Report for 1867—1869 it is stated that most of the sea trout entered the smolt stage in September and October, 1867, and were released in the River Plenty. In a paper by Allport (1870 b), one of the Salmon Commissioners, it is stated that the remainder of the sea trout parr migrated to the sea as smolts in October, 1868, with the exception of some retained for breeding stock. Two fish, described as smolts, were taken in the Derwent estuary in October, 1869, and sent to A. Gunther, of the British Museum, for identification (Allport, 1870 a). The fish, which were about 10 inches long, were identified as sea trout. Allport (1875) describes a fish taken in the Derwent in December, 1873, and considered it to be a salmon ( Salmo solar). There is no convincing evidence that salmon were ever established in Tasmania, and the description could have applied to a sea trout. In the Royal Commission Report (1882) it is stated that smolts from the River Plenty and specimens from the River Derwent were identified by Gunther as sea trout. The report further states that the sea trout is thoroughly established and is the principal commercial species.

From the above, it appears that eggs taken from reputed sea trout in the River Tweed gave rise in Tasmania to a stock of fish which showed a smolt migration to the sea, and specimens of which were identified as sea trout by Gunther.

Establishment of the Thames-Itchen Stock in New Zealand

The history of this stock has been described by Arthur (1882) and Thomson (1922), and it is necessary to confirm that the stock did come from Tasmania, and that no stocks came from other sources until much later.

The first introduction was made by the Canterbury Acclimatisation Society in 1867 when 800 ova were obtained. Of these, 3 fish hatched and 2 were later reared to maturity. The circumstances are described in the 4th-6th Annual Reports of the Canterbury Acclimatisation Society (1868-1870), and by Thomson (1922, p. 212) and Farr (1880). The dispatch of the ova from Tasmania is confirmed by the Salmon Commissioner’s Report (1867).

In 1868, four acclimatisation societies made successful introductions from Tasmania. The Salmon Commissioner’s Report (1869) states that ova were sent to the provinces of Southland, Otago, Canterbury and Nelson, and the arrival of the four shipments is noted in the Otago Daily Times of 15th September, 1868. Confirmation of successful hatching and liberation is given for Otago (O.A.S. sth Ann. Rep., 1869) and Canterbury (C.A.S. sth Ann. Rep., 1869).* The Annual Reports of the Southland Acclimatisation Society have been lost, but a history of this society is given by Stock (1916), a former member of the council, and the introduction is confirmed. No records exist for the Nelson Society, but in view of the success of the other three shipments it is probable that this society was also successful (Thomson, 1922).

Successive shipments to New Zealand continued until at least 1874 (Salmon Commissioner’s Report, 1877), these being all of the same stock. During this period there is no evidence of importations of brown trout from Europe, and it was not until 1883 that such an importation was made.

Introduction of the Tweed Sea Trout to New Zealand

Before enumerating the individual shipments it is necessary to establish that the sea trout ova supplied from the hatchery on the River Plenty were from the original stock. Allport (1870 b) discusses this point and states that 12 individuals from the 1866 shipment matured in the winter of 1869, and that some of the progeny of these twelve fish were retained to add to the breeding stock. Both Allport (1870 b) and the Salmon Commissioner’s Report (1869) state that the sea trout retained for breeding stock were placed in a separate pond fed by a separate spawning race. The Report of the Royal Commission (1882) states that the original 12 sea trout lived till about 1873, but that the progeny of this group were used for breeding. This second group of sea trout resembled the parents and did produce ova. It can therefore be said that from 1870 to 1876 the sea trout ova sent from Tasmania to New Zealand were from the Tweed sea trout stock which arrived in Tasmania in 1866.

Southland

Stock (1916) notes that the secretary of the Southland Acclimatisation Society, E. D. Butts, returned from Tasmania with sea trout ova in September, 1870, and that 154 were laid down at the Wallacetown hatchery. Confirmation is given by the Salmon Commissioner’s Report (1873) where it is recorded that 200 sea trout ova were sent to New Zealand in 1870. Stock states that the sea trout were held until maturity and that in 1874 1,100 ova were obtained and the resulting young fish released in the Oreti. Stock’s actual wording does not indicate when the young sea trout were released, and letters from the National Archives provide information. One letter is from H. Howard (N.A, 13832) curator to the society, and is dated 16th December, 1875. Howard states that he has 2,000 sea trout fry at the hatchery. A letter (N.A. 13832/73) from Dr J. A. Menzies, vicepresident of the society, dated 26th January, 1876, gives a list of fish distributed from the hatchery by Howard. This gives the release of sea trout as 850 in the Oreti and 250 in the Wyndham. The two letters indicate that the sea trout were released in late December, 1875, or early January, 1876. Since Stock’s account is farther in time from the actual events, it is preferable to accept the more detailed statement by Menzies that the fish were released in the two rivers. The

discrepancies in dates offer some difficulties, since Howard refers to his fish as fry in 1875 and Stock states that ova were obtained in 1874.

If Stock is right in both date and locality, then it could be that ova were obtained in 1874 and 1875. If Stock is incorrect in his date then the sea trout had taken an unusually long time to come to maturity. The statement of Menzies on the release can be accepted without excluding the possibility of a liberation in 1874.

Otago

In the winter of 1870 the manager of the Otago Acclimatisation Society, G. P. Clifford, returned from Tasmania with sea trout ova, and every fish hatched successfully (O.A.S. 7th Ann. Rep., 1871). The Minute Book of this Society for 13th October, 1870, records that 142 sea trout fry were counted. A discrepancy in that the total number of ova arriving in New Zealand in 1870 was approximately 300, while the Salmon Commissioner’s Report (1873) records that 200 ova were sent, can be resolved by assuming that the 200 was an estimate and that 300 were actually sent.

The fry were retained for a short while, and in December, 1870, 134 sea trout were taken to a pond near the River Shag at Palmerston, maintained by W. A. Young (O.A.S. 9th Ann. Rep., 1874). The date and number of fish are confirmed by the Minute Book for 22nd December, 1870, when Clifford reported that he had taken the sea trout to Palmerston.

At a meeting of the Otago Branch of the New Zealand Institute J. S. Webb (1874), who was a council member of the Otago Acclimatisation Society, stated that W. A. Young had informed him that about 120 young sea trout were released in the Shag in 1872. In the 9th and subsequent Annual Reports of the Otago Acclimatisation Society the number of fish released is given as 134. It is unlikely that 134 fish could be held for over a year in a pond without losses, and since Young himself reared the fish, his reported statement on the number is accepted.

A second lot of Tweed sea trout ova was sent from Tasmania to Otago in 1876, but the ova failed to hatch (O.A.S. 11th and 12th Ann. Reps., 1878). The Salmon Commissioner’s Report (1877) in the return for 1876, confirms that 250 sea trout ova were sent to New Zealand.

Canterbury

In the winter of 1873 the Canterbury Acclimatisation Society imported 300 sea trout ova from Tasmania, of which 49 hatched (G.A.S. 10th Ann. Rep., 1874). The despatch of the ova is confirmed by the Salmon Commissioner’s Report (1877).

In the next annual report (C.A.S. 11th Ann. Rep., 1875) sea trout are listed as part of the stock in the garden ponds in 1874, but in subsequent annual reports no further mention is made of this stock. It is unlikely that the stock was disposed of between 1874 and 1875, and, since the reports of this society are unusually brief, it seems likely that not all activities were fully reported. The Minute Book provides no information, but some indication of the council’s policy towards this stock is obtained from a letter written by S. C. Farr, secretary of the society, to J. W. Agnew, of Tasmania, and dated 30th September, 1873 (C.A.S. Letter Book, 1869-1874). Farr says that the sea trout fry will be used to stock one river in a few years’ time. This would imply that the fish were to be kept to maturity.

The curator for the society at this period was A. M. Johnson, and in a letter to Archdeacon Davies, dated 7th February, 1874, he states that the 49 young sea trout are progressing favourably (G.A.S. Letter Book No. 81). No further evidence for this period appears in the records of the society, but a letter from A. M. Johnson in the Christchurch Press of 6th August, 1895 (this letter is also quoted in part by Thomson, 1922) describes the history of the stock, the details agreeing with the above account, and then states that at about four years old the sea trout spawned in a race entering the pond. He adds that he could not determine from Farr what happened to the stock. Johnson was curator until September, 1875, so that it is not possible to decide whether his report of the spawning was based on visits to the society’s grounds, or on reports from others.

Thus, although this society possessed a stock of Tweed sea trout in the 1870’s which they apparently proposed to release, there is no definite evidence that they were put in any river.

After leaving the employment of the society, Johnson established himself as a private fish culturist at Opawa, Canterbury, and appeared to have breeding stocks of several species. In a letter to the Colonial Secretary dated Bth June, 1886, he states that he imported sea trout, Lochleven trout, and Scotchbum trout from Sir J. Maitland of Howietoun (Johnson, 1886). Johnson, unfortunately, left no complete record of his activities, but it seems very probable that he distributed the fish mentioned to private individuals.

The Introduction of the Hodder Sea Trout to New Zealand

In addition to the Tweed sea trout a stock was brought directly from England, and since its existence has been largely overlooked it is necessary to consider the evidence in some detail.

Nicols (1882) states in an appendix that the Celestial Queen shipment included 4,000 sea trout ova but gives no further details. The shipment had been requested by the Provincial Government of Otago and the collection and packing of the ova supervised by J. A. Youl (Nicols, 1882, p. 207), and while most of the shipment consisted of Atlantic salmon ova smaller lots of sea trout, brown trout, and a species of char were included. Although the Provincial Government presumably kept records of the management of this shipment, only a few letters relating to this work were located in the National Archives, and the main source of information was found to be the Otago Daily Times, published in Dunedin.

The Provincial Government had asked W. C. Young, a former resident of Dunedin, to supervise the arrangements for the shipment in London. In a letter to the Superintendent of Otago (O.D.T.* 28th March, 1868) Young states that the Celestial Queen left the docks on 16th January, 1868, and that the shipment included 9 boxes containing 4,000 sea trout ova. In a further letter (O.D.T. 3rd April, 1868) Young confirms the number of ova and states that they are from the River Hodder, England. In a letter from Youl to J. Auld, the Edinburgh agent for the Provincial Government, Youl describes the supervising of the shipment (O.D.T. 3rd April, 1868). Young assisted Youl in the packing, and although Youl does not mention the origin of the sea trout ova, it seems that Young noted the details of each lot of ova as they arrived at the docks.

Youl’s remarks on the sea trout are significant:

“ Mr Ramsbottom, senior, at my request, brought up in water about 5,000 eggs of the sea trout, in first rate condition, which I packed most carefully, as they will go with the salmon, and are a most valuable fish, and give most excellent sport to anglers.”

Ramsbottom resided in Glitheroe, Lancashire, and was thus close to the Hodder which at that time was noted for sea trout (Grimble, 1913). It is quite likely, therefore, that Ramsbottom on receiving Youl’s request would visit a river which was both familiar and likely to hold suitable fish. The position adopted here is that the eggs were taken from Hodder sea trout by an experienced worker.

The Celestial Queen arrived at Port Chalmers on 2nd May, 1868, and an account of the unpacking is given (O.D.T. 4th May, 1868). It appears that the salmon and sea trout were to be handled by the Government, while the brown trout and char were presented to the Otago Acclimatisation Society (the brown trout failed to hatch). Part of the Government’s shipment (nine boxes of salmon ova and one box of sea trout ova) was transferred to a hatching site on the Water, of the Leith, while the remainder was taken to a hatchery on the Waiwera, a tributary of the River Glutha. In an account of the unpacking (O.D.T. Bth May, 1868) it is stated that two boxes of sea trout were opened immediately, and Dawbin, who was in charge, reported that a large proportion of the eggs was in excellent condition. The first hatching occurred at the Water of Leith on 24th May, but the report mentions only salmon. On the 28th May Dawbin reported that hatching had begun and that 50 fry were noted (O.D.T. 29th May, 1868). Dawbin does not state the species and there is no further mention of the sea trout in statements of Dawbin or others, the only fish indicated being the salmon. In a report Dawbin (1869) describes a flood lasting from 20th to 27th May and considers that this had an adverse effect on the ova as only 500-600 fry appeared. In two letters from Dawbin to the Secretary of Lands and Works dated sth and 23rd November, 1869 (N.A. Nos. 9272/151, 9272/48) salmon smolts are mentioned and the formation of shoals is noted. It appears that the change to smolts indicated to Dawbin the appropriate time for the release of the fish for, in a report in the Evening Star (Dunedin) of 30th November, 1869, Dawbin states that 150 salmon have left for the sea and that more will follow, while 100 will remain until next season. The remaining fish were released prior to 24th March, 1870, when Dawbin left the hatchery (National Archives, Letter No. O P 7/74 9272).

From this it appears that the fish that did hatch out were released into the Waiwera during 1869 and 1870, and it remains to consider whether the absence of any remarks on the sea trout means that they failed to hatch.

It is necessary to turn to the one box of sea trout ova which was under the care of G. Duncan at the Water of Leith. W. Arthur (1881) notes a statement from A. G. Begg that Duncan released sea trout in the Water of Leith in 1870 or 1871. Begg was secretary of the Otago Acclimatisation Society from 1874 to 1883, and the sea trout released must have been those from the Celestial Queen shipment. This release is reported by the Otago Society (O.A.S. 16th Ann. Rep., 1882) where the number of fish is given as 20 and the year as 1871. Since one box at the Leith containing approximately 450 ova resulted in the release of fish, then it seems likely that 8 boxes taken to the Waiwera should have resulted in a larger number of fish. Against this must be set the flood which occurred before

hatching and the fact that the total number of fish hatched was 500-600. In considering this number it cannot be assumed that the salmon and sea trout experienced similar mortalities. Young (O.D.T. 28th March, 1868) states that the salmon ova are from four different rivers and gives the number as 220,000. Youl (O.D.T. 3rd April, 1868) expresses concern over the Irish and Scottish ova and states that at least 160,000 have been packed in the best possible condition.

At the unpacking (O.D.T. Bth May, 1868) most of the salmon ova appeared dead, whereas both Youl (during packing) and Dawbin (during unpacking) commented on the good condition of the sea trout ova. The only estimate available of the ova finally put in the hatchery as healthy comes from an anonymous article in the Field for January 26th, 1878, quoted by Nicols. The letter states that 20,000-30,000 healthy ova were put in the boxes, and it is suggested that the proportion of sea trout ova in the total ova laid down was greater than the proportion of sea trout in the total ova packed in London. Although one box of sea trout ova at the Leith gave approximately 5% in young fish released this proportion cannot be applied to the Waiwera fish because of the flooding.

Nicols (1882, p. 87) reported that a salmon grilse of 31b weight was taken in the Clutha in the middle of 1874, but no further details are given. There are many instances during this period of reported captures of Atlantic salmon both in New Zealand and Tasmania. Those fish that were examined were usually identified as sea trout, as will be shown below. There are no records of Atlantic salmon from the Clutha, and if the fish taken resembled a salmon sufficiently to cause comment, then it is highly probable that it was a sea trout.

Finally, it should be noted that the sea trout in this shipment were included at Youl’s request, and the main interest in New Zealand was focused on the salmon. If, as seems possible, some sea trout did hatch out then Dawbin presumably reared them together with the salmon. Until further evidence is available, it is proposed to regard this as a possible release.

The known and possible releases of sea trout noted above are summarised in Table 1, and in Fig. 1 the locations of actual and possible releases are given.

Incorrect Reports

Although there is little published material on the introduction of sea trout to New Zealand, Stokell (1955) gives some details. He states that the Otago Acclimatisation Society liberated sea trout obtained from Tasmania in the Water of Leith, but there is no evidence in the Society’s detailed records to support this statement. The evidence available indicates that sea trout of the Hodder stock

were put in the Leith. Stokell also states that the Wairarapa Society received sea trout ova from a Government shipment in 1844, and that in the same year the Wellington Society received sea trout ova from Scotland imported for the Otago Society. At this time the Otago Society was attempting to obtain a stock of Lochleven trout from Howietoun hatcheries, Scotland, and after several attempts a shipment reached Dunedin in January, 1884, This shipment is described in a letter from W. Arthur to Sir J. G. Maitland, dated 23rd May, 1884 (Maitland, 1887). Arthur mentions that some of the ova were left at Wellington, and there is no doubt that the ova were from Lochleven trout. The report of sea trout received by the Wellington Society in 1884 appears, therefore, to be incorrect.

In the same letter Arthur refers to another shipment made by the New Zealand Government from Howietoun which arrived in Wellington in March, 1884, and Arthur is under the impression that sea trout had been sent. However, the Minute Book of the Otago Acclimatisation Society for 19th September, 1884, reports a letter from Maitland which states that no sea trout had been sent in the Government shipment, but only Lochleven trout. This is further confirmed by an Annual Report (0.A.5., 19th Ann. Rep., 1855), which describes both shipments and states that only Lochleven trout were sent. In the reports of the Wairarapa Society (Ist Annual Report Wairarapa Acclimatisation Society, 1884, and subsequent reports) it is stated that sea trout ova were received from the Government in 1884, and subsequently distributed. The ova in question must have been from Lochleven trout, so that no sea trout were distributed by this society.

The Establishment of Sea Trout in New Zealand

It is now necessary to consider whether or not the sea trout released during the first decade of salmonid introduction did develop into breeding populations. The evidence available comes from amateur or professional workers of the period and the initial problem of recognisable differences between brown trout and sea trout populations must be faced. Since it is proposed to discuss this more fully in a subsequent paper, the conclusions drawn here are necessarily tentative, and the literature will not be considered fully.

It is convenient to take Gunther (1866) as a starting point, for he examined many salmonids sent from New Zealand, and his views were familiar to most of the naturalists in New Zealand concerned with trout. Gunther distinguished many populations of trout in Britain as separate species and gave diagnostic characters for each species. Day (1880-1884, 1887) considered that the differences used by Gunther were not constant, and included all the populations under Salmo trutta L. In discussing the differences Day (1887, p. 177) considered that sea trout and fresh-water trout were local races of one species, that migratory or fresh water habits may result from local circumstances, and that colours were dependent on immediate surroundings. Regan (1911, p. 56) states that although brown trout and sea trout differ in habits and appearance, there are no structural differences, and he treats them as one species. Regan’s statement on the absence of structural differences has been quoted by almost all writers on this topic, and can be regarded as the prevailing viewpoint. Trewavas (1953) in a recent review agrees that no structural differences have been established but makes no definite comment on other differences.

It must be noted that this view does not exclude the possibility of recognisable differences between the two types, and experienced field workers are usually able to separate the types even at spawning time. The distinctions made by these workers are verified by the fact that progeny from the two types do develop the parental characters under normal circumstances. An interesting early example is given by Shaw (1844). He took a pair of spawning fish, which he considered to be sea trout, in a tributary of the River Nith, Scotland, and reared the progeny. At the age of two years the young assumed the characters of sea trout smolts. Shaw also marked descending sea trout smolts, and recovered the marked fish later as adult sea trout. It has been noted above that the shipment of ova to Tasmania in 1866 included ova stated to be from sea trout taken by W. Ramsbottom in the Tweed, Scotland. This lot of ova eventually gave rise to smolts which were released in the Derwent. Adult fish recaptured later in this river were identified as sea trout by Gunther. More recently the Lancashire River Board supplied the Otago Acclimatisation Society with ova stated to be from sea trout from the River Gilpin, Westmorland. The parent fish were taken by experienced water bailiffs and the fry hatched at the Society’s hatchery in March, 1960. In the spring of 1961 (October) 10% had changed into smolts, agreeing with published descriptions of sea trout smolts. An example on a larger scale is provided by Allom (1960). The River Grudie, Scotland, was stated to contain only brown trout, and had three falls which offered difficulties to migrating fish. An unspecified number of sea trout fry were put in the river in 1928, and in 1936 3,000 sea trout fry were added. In 1937 and 1938 the falls were altered and a fish ladder built, and in 1939 two sea trout were caught in the river. If two fish were caught it is probable that there were substantially more in the river. It may be argued that the removal of obstructions in 1937 and 1938 allowed sea trout to run up the river, and that the sea trout taken in 1939 and later were not necessarily older fish from the fry added in 1936. The existence of homing makes it unlikely that sea trout in appreciable numbers would run up the Grudie as soon as the obstruction was removed, and the same homing tendency makes it more likely that the sea trout taken were those that had been released in the river as fry. At present there is a large spawning run of sea trout in the river.

The above indicates that there are recognisable differences between brown trout and sea trout, these differences being apparent at spawning time in fresh specimens. From the viewpoint of the present problem it can be said that observers in New Zealand could usually, if they had previous experience in Britain, separate brown trout and sea trout in the field.

Otago

The liberation of sea trout in at least two rivers in this province has been established, and there are numerous reports of sea trout from this area from 1874 onwards. The Annual Reports of the Otago Acclimatisation Society record captures of sea trout from Otago Harbour from 1874 to 1882. In 1875, it is stated that a breeding population has been established, since fish from 11b to 71b in weight have been taken (O.A.S. 10th Ann. Rep. 1875). Concern was felt at the time over the 'illegal capture of these fish in Otago Harbour, and in one instance a fine of £25 was imposed for possession of sea trout (O.A.S. 14th Ann. Rep. 1880).

Identifications were made by a number of naturalists, of whom W. Arthur was the most important. Since this worker provided much information on the early development of salmonid stocks, it is important to attempt an assessment

of his reliability as an observer. Arthur (1837-1885) was born in Dunbarton, Scotland, and was trained as an engineer and surveyor. He came to New Zealand in 1860, and his earlier interest in angling led him to a serious study of both marine and freshwater fish. He was the author of eight published papers on fish in New Zealand, and was acquainted with the writings of Yarrel, Gunther, Day and others. He was well aware of the variability of salmonids from his experience in Britain and New Zealand, and his own work conveys the impression of a careful and honest observer.

In his first paper on trout (Arthur, 1879) he gives drawings of the heads of three fish which he considered to be sea trout and for comparison gives drawings of the heads of brown trout. In comparison, he states that the maxilla is shorter and finer in the sea trout than in the brown trout, that the free margin of the sub-operculum is rounded in the sea trout and angular in the brown trout, and that there are fewer opercular spots in the sea trout. Arthur’s figures are reproduced in Fig. 2, and the relevant details added. He also refers to a number of other fish taken near Dunedin, which he saw and considered to be sea trout. Although the written description is not detailed, the character differences for the maxilla and the opercular spots is not inconsistent with distinctions commonly made in the field.

In a paper dealing with migratory salmonids (Arthur, 1881) a detailed description is given of a fish taken in Otago Harbour, 27th April, 1880. Arthur compares this specimen, a 21b 14oz female with two sea trout from the River Clyde, Scotland, and the River Usk, Wales, as well as with descriptions by Gunther and Yarrel. Among the morphological characters mentioned are the short, fine maxilla, rounded margin of suboperculum and absence of teeth from shaft of vomer. It is of more interest, at this point, to compare the colouration of Arthur’s specimen with published descriptions. Not all of the older authors are used, and only descriptions of fish fresh from the sea are included. Where descriptions are given under several specific names, those referring to Salmo trutta are chosen as giving a valid comparison with fish possibly originating from the Tweed or Hodder. Couch (1877) is omitted, since his coloured plates seem misleading and his written description inadequate. Where comparison can be made agreement is good. The descriptions of the pectoral fin show much variation, but this can be explained by examination of fresh specimens. If the fin is examined in isolation it seems to be colourless or pale gray except for dark gray streaks on the medial aspect. If the fin is now laid flat against the body of the fish, it appears to be a pale bluish gray. The different authors were describing the fin in different positions. Arthur also states that the Harbour fish is identical with the fish taken at Otago Heads, April, 1874, in colouration. This latter fish is preserved in Otago Museum, and the head is seen in Fig. 2.

Arthur concludes (p. 190) that his fish is a sea trout (Salmo trutta) and the agreement in colour pattern is obviously close. He comments on two further characters on the trout from Sawyers’ Bay which he considers are not found in typical sea trout and brown trout. The lower jaw projects quite markedly beyond the upper in both sexes when the mouth is closed, and this feature was apparent in all the fish that he regarded as sea trout from Otago Harbour. He expresses some doubt over a fish from Lake Wakatipu with an identical head, and states that no sea trout were liberated in any feeder of the Glutha. However, as discussed above, it is possible that this did occur, and Lake Wakatipu drains into the Glutha. Since the sea trout in the Otago Harbour and possibly also in the Clutha could have been derived from a fairly small number of ova, it is likely that

only a few parent Hodder fish were involved. The distinctive lower jaw noted by Arthur could thus have been a character present in one or more members of the parental group.

The second peculiarity concerns the maturity of the fish. Although the female was taken at the end of April, it was clearly not going to spawn that winter*.

This, however, is quite consistent with the identification as sea trout, since Nall (1938) and others have shown that sea trout may spend one or more winters in the sea as maiden fish. It is much more difficult to reconcile the failure to spawn at this size with an identification of brown trout.

In the same paper Arthur notes that brown trout (Salmo fario ) may visit the sea and develop a silvery appearance, thus making distinction between the two types more difficult. He considers, however, that certain characters can still provide a distinction including details of structure and colouration.

In his final paper on trout Arthur (1884, p. 499) comments on the tendency of the brown trout in the Water of Leith to migrate to Otago Harbour. He states that these tend to resemble sea trout in appearance, but adds that only marking would give definite proof of identity. He then states that sea trout are present in the harbour but are becoming scarcer each year.

The first reported identification of a sea trout appears to have been made by F. W. Hutton. Hutton held a number of scientific posts and was the author of numerous papers on the New Zealand fauna. In April, 1874, at a meeting of the Otago Institute, he exhibited a fish which he identified as a sea trout and said that another had recently been caught (Hutton, 1874). The fish exhibited is now in the Otago Museum and is shown in Plate 1.

G. M. Thomson states (1922, p. 202) that he was dredging in Otago Harbour at the time of Hutton’s identification. He notes that the fishermen distinguished between two types of trout taken in their seine nets, and considers that these were sea trout and brown trout

Canterbury

In 1888 a supposed specimen of Salmo salar taken from Timaru harbour was sent to the Otago Acclimatisation Society for identification (O.A.S. 22nd Ann. Rep., 1888). This was examined by Professor J. T. Parker, of Otago University, and after comparison with specimens in the museum was identified as a sea trout (Salmo trutta) .

In 1889 the Canterbury Acclimatisation Society sent a fish to Dr Gunther, British Museum, and Gunther’s reply is quoted (Thomson, 1922, p. 191). The fish came from the River Selwyn and from the letter it seems the Society had thought it to be a salmon ( Salmo salar). Gunther states that it is a migratory trout and not a common trout ( Salmo fario).

In 1895, a fish considered to be a salmon was taken in the Opihi and sent to Gunther for identification. Part of the letter in reply is quoted by Thomson (1922, p. 211) but the entire letter appears in a book of newspaper cuttings belonging to the Southland Acclimatisation Society, and is reproduced here:

British Museum (Natural History), Cromwell Road, London, S.W

April 2nd. 1895

Dear Sir,

The fish mentioned in your letter of January 23 reached me today. Although the ice was thawed when I opened the case, the specimen was in perfect condition for examination. It is without question a genuine sea-trout. The short tail, the small scales of the tail, the teeth on the palate, the number of Pyloric appendages (49), the form of the praeoperculum are all as generally found in the most typical specimen of British sea-trout. The specimen has none of the specific characteristics of the salmon. It is certainly as silvery as a fresh-run salmon, but so are many sea-trout when fresh from the sea.

The specimen is a female with the ova well developed, which might have been ready for spawning in three or four weeks. It is of great beauty and fatter than I have ever seen a sea-trout or salmon, showing it must have had abundance of food, and grown up under the most favourable conditions. It has been stated (erroneously as in my opinion) that Salmonoides change their specific characteristics when transplanted from the Northern to the Southern Hemisphere. The specimen sent by you is strong evidence that no such change has taken place in your New Zealand Salmonoides.

Believe me,

Yours truly,

A. GUNTHER,

H. A. Bruce, Esq.

The above fish was caught by Mr A. P. O’Gallaghan, of Timaru, in the Opihi, and was supposed by him to be a salmon. The Society forwarded the fish to Dr Gunther for identification.

Southland

In October, 1891, the Southland Acclimatisation Society sent three fish to the Field, London, for identification. These were forwarded to Gunther, and the circumstances are described in the Field, 9th January, 1892. The fish were taken from the estuary of the Aparima, and were thought by the senders to be salmon. Gunther in his reply writes that the fish are neither salmon (Salmo solar) nor brown trout (Salmo fario) but a kind of sea trout (Salmo trutta ).

In assessing the evidence it may be objected that in some cases the number of sea trout released was small and unlikely to develop into breeding populations. It should be noted, however, that at this period the rivers did not yet have well developed populations of brown trout, and before the smolt migration the sea trout would suffer little from intraspecific competition. Intraspecific competition is usually considered to have more marked effects than interspecific competition, and there are examples from New Zealand of establishment of breeding populations of brown trout from small liberations. In the marine phase the sea trout would experience predation by fish and birds, but the severity of this cannot be estimated.

It may also be noted that Arthur (1879, 1881) states that no sea trout were taken in any of the rivers. The significance of this statement is difficult to evaluate, but Arthur expected to detect young sea trout in the rivers. These would be readily detected only during the smolt migration. It is curious, however, that Arthur did not observe any in the Water of Leith during the spawning season. The incomplete state of knowledge on the relative status of brown trout and sea trout makes it difficult to assess the above evidence, but it must be acknowledged that recognition of putative sea trout in the field and production from them of progeny which resemble the parents is strong evidence that usable criteria for separating the two types do exist. Since the identifications were made over a period of years by competent naturalists, and since the specimens were taken from the south-east of the South Island (the original release area) it is concluded here that the fish in question would correspond to fish identified as sea trout in Britain at that period.

Discussion

It has been argued that the releases of sea trout did result in breeding populations, and it is desirable to examine the views of successive commentators on the trout in coastal waters.

The observers in Otago expressed no doubts about the identity of the fish and the identifications made in Britain seem to support this attitude. Thus Arthur, writing in 1879 and 1881, appears satisfied that the trout in question are sea trout. Although he admits that brown trout may visit the sea and become silvery (Arthur, 1881, p. 192) he considers that they can be distinguished from sea trout. Later (Arthur, 1884, p. 499) he states that brown trout (Salmo fario) are frequently taken in the harbour, and that they tend to assume the appearance of sea trout.

Thomson, who was actively interested in fisheries in Otago over the period under consideration, comments as follows (Thomson, 1922, p. 208): “ The first record of trout in Otago was in 1868, but no sea trout were included. In those early days there was no doubt expressed, such as arose later in regard to fish caught in sea-water, as to the difference between sea trout and brown trout.”

On the same page he points out that the fishermen in Otago Harbour always distinguished at that period between “Salmon” and “Trout”.

The first observer to throw doubt on the existence of sea trout in New Zealand was Hector (1881). He gives a description of a fish taken in Nelson Harbour, and identifies it as a sea trout. His own doubts about the status of this fish, and of the fish identified as sea trout on the Otago Coast are then expressed. These doubts were, however, based on an inadequate grasp of events, for he states that the only sea trout released in New Zealand were those put into the Shag, and that the number did not exceed seventy or eighty. He then goes on to suggest;

. . what we know as brown trout in the rivers are of the large fastgrowing variety known as the Thames trout, but which, in New Zealand, enter the sea, and acquire the characters of true sea trout.”

There is no doubt that brown trout do enter the sea, but it has still to be satisfactorily demonstrated that such trout develop during their marine existence all the characters associated with sea trout. Hector need not have made this assumption, if he had considered the evidence which must have been readily available to him. Most subsequent writers, unfortunately, followed Hector by overlooking the evidence and by adopting the view that the trout population in coastal waters was derived from brown trout.

Spackman (1892) in a book on trout fishing in New Zealand, acknowledges his debt to W. Arthur, but on p. 82 he queries the identification of sea trout from the Aparima by Gunther. Although Arthur (1882) states that sea trout were released in the Oreti, Spackman states that no sea trout were put in any river near the Aparima. E. Tanner comments on Spackman’s book (Southland News, 27th October, 1892), and adopts Hector’s assumption. Although Tanner was secretary to the Southland Acclimatisation Society, in discussing the trout in the Oreti he overlooks the fact that his own Society released sea trout in the Oreti.

In this way, the early introductions of sea trout were largely overlooked by a number of writers in New Zealand, although later authors such as Donne (1927) and Stokell (1955) continued to note some details of the introductions.

In Europe, Day (1887) was the first worker to discuss the problem at length. On p. 7 he quotes Arthur (1884) as saying that brown trout are taken in Otago Harbour, and from this Day argues that the brown trout are becoming anadromous. He also refers to a 251 b trout, silvery and marked with black cruciform spots taken from the Waimakariri, and reports that trout caught previous to 1878 were marked with red spots, but are never seen now. Day considers this to be evidence that the non-migratory brown trout had assumed the habits and appearance of sea trout. On p. 145 Day refers to another part of the same paper, but does not comment on Arthur’s statement about the taking of sea trout in Otago Harbour. On pp. 183-184, Day refers to Arthur (1879) but ignores the recorded release of sea trout in the Shag, and Arthur’s description of sea trout taken in Otago Harbour. Day (1887, p. 173) had also read Arthur’s paper (1882) on the history of fish culture in New Zealand where he (Arthur) mentions the sea trout from the Celestial Queen, and the releases in the Oreti and the Shag. It is remarkable, therefore, that Day, in discussing the trout in the sea, makes no reference to the releases of sea trout. Day, however, uses the evidence from New Zealand to support his views on the relative status of brown trout and sea trout. He was followed in Britain by Calderwood (1907), Regan (1911) and Lamond (1916), none of whom appeared to have consulted Arthur’s papers.

The now widespread view that the brown trout introduced to New Zealand gav( rise to all stocks of trout migrating between rivers and the coastal waters, and resembling sea trout, is not based on substantial evidence. It is to be expected that some members of mainly river-dwelling populations did, and still do,

migrate to the open sea, but their contribution to the total stocks of trout in the sea cannot be properly evaluated without considering the introductions of sea trout. Although these have been largely overlooked, it appears that breeding populations were established, and that for a few decades after the introductions sea trout were common in coastal waters. The relationships between brown trout and sea trout during this period cannot be studied directly, and the problems can be taken further only by a study of present day populations.

Acknowledgments

I should like to thank the Acclimatisation Societies of Southland, Otago, and North Canterbury for permission to examine their records, the officers of the National Archives for the location of reports, and Dr R. Forster for permission to examine specimens in Otago Museum. I am indebted to Dr A. G. Nicholls for drawing my attention to the Royal Commission reference to the origin of the sea trout in Tasmania. I am grateful to K. R. Allen for criticising the manuscript.

References

Allom, P. G., 1960. Birth of a salmon river. Salmon & Trout Mag., 160: 226-228.

Allport, M., 1870 a. Brief history of the introduction of salmon ( Salmo solar) and other Salmonidae to the waters of Tasmania. Proc. Zool. Soc., 1870: 14-30.

Proc. Zool. Soc., 1870: 750-752.

waters. Proc. Roy. Soc. Tasmania, 1874, 12—18.

Arthur, W., 1879. On the brown trout introduced into Otago. Trans. N.Z. Inst., 11; 271-290.

13: 175-193.

Bugkland, F., 1883. The natural history of British fishes.

Calderwood, W. L., 1908. The life of the salmon.

Canterbury Acclimatisation Society, 1868-1875. 4th-llth Annual Reports. Letter books No. 81, 1869-1874.

Christchurch Press, Christchurch. Issues in 1873, 1895.

Gough, J., 1877. A history of the fishes of the British islands.

Dawbin, R., 1869. Letter to Macandrew. Appendix Jls. House Rep., Dls.

Day, F., 1880—1884. British and Irish fishes.

Donne, T. E., 1927. Rod fishing in New Zealand waters.

Evening Star, Dunedin. Issue in 1869.

Farr, S. C., 1880. A brief history of trout culture and distribution by the Canterbury Acclimatisation Society.

Field, London. Issues in 1878, 1892.

Francis, F., 1879. Trout in the Antipodes The Field, p. 359.

Grimble, A., 1913. The Salmon Rivers of England and Wales.

Gunther, A., 1866. Catalogue of fishes. 6.

Hector, J., 1882. On the occurrence of the salmon trout in Nelson Harbour. Trans. N.Z. Inst., 14; 211-213.

Hobbs, D. F., 1948. Trout fisheries in New Zealand. Fish. Bull. Wellington, N.Z., 9.

Houghton, W., 1879. British fresh-water fishes.

Hutton, F. W., 1874. Trans. N.Z. Inst., 6: 447.

Johnson, A. M., 1886. Letter to Colonial Secretary. Appendix Jls. House Rep., H 7a.

Johnston, R. M., 1883. On the fishes of Tasmania. Proc. Roy. Soc. Tasmania, 1882* 53-144.

Lamond, H., 1916. The sea-trout.

Maitland, J. R. G., 1887. The history of Howietoun.

Menzies, J. W. M., 1936. Sea trout and trout.

Nall, G. H., 1930. The life of the sea trout.

New Zealand National Archives, Wellington. Letters numbered 13832, 13832/73, 9272/48, OP 7/74, 9272.

Nigols, A., 1882. The acclimatisation of the Salmonidae at the Antipodes.

Otago Acclimatisation Society, 1869-1888. sth-22nd Annual Reports. Minute Books.

Otago Daily Times, Dunedin. Issues, in 1868.

Parnell, R., 1838. On the fishes of the district of the Forth. Memoirs Wernerian Nat. Hist. Soc., 7: 161-520.

Ramsbottom, R., 1854. The salmon and its artificial propagation.

Regan, G. T., 1911. British freshwater fishes.

Royal Commission on the Fisheries of Tasmania, 1882. H. of Ass. Pari. Papers 132.

Salmon Commissioner’s Reports, Tasmania, 1864. H. of 455. Jls., paper 41.

Seaoer, P. S., 1889. A concise history of the acclimatisation of the Salmonidae in Tasmania. Proc. Roy. Soc. Tasmania. 1888: 1-26.

Seeley, H. G., 1886. The fresh-water fishes of Europe.

Shaw, J., 1844. On the growth and migration of the sea-trout of the Solway ( Salmo trutta ). Trans. Roy. Soc. Edinburgh. 15: 369-375.

Skroghowska, St., 1959. Migrations of sea trout, brown trout and their crosses tagged as smolts in the Vistula. /. Cons. int. Explor. Mer. Salmon & Trout Committee No. 115.

Southland News, Invercargill. Issue in 1892.

Spackman, W. H., 1892. Trout in New Zealand.

*Stogk, A. H., 1916. History of the Southland Acclimatisation Society.

Stokell, G., 1955. Fresh water fishes in New Zealand.

Tchernavin, V., 1939. The origin of the salmon. Salmon and Trout Mag. 95: 120-140.

Thomson, G. M., 1922. The naturalisation of animals and plants in New Zealand.

Trewavas, E., 1953. Sea trout and brown trout. Salmon and Trout Mag., 139: 199-215.

Vladykov, V. D., 1934. Environment and taxonomic characters of fishes. Trans. Roy.

Canad. Inst., 20: 99—140.

Wairarapa Acclimatisation Society, 1884. Ist Annual Report.

Webb, J. S., 1874. Trans. N.Z. Inst., 6: 447.

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D. Scott, Zoology Department, University of Otago, Dunedin, New Zealand.

* Footnote. The contractions 0.A.5., and G.A.S. are used for Otago Acclimatisation Society and Canterbury Acclimatisation Society respectively.

* O.D.T. is used for Otago Daily Times.

* Where no number is given, release of fish has not been definitely established.

* Taken partly from coloured plate.

* Almost all spawning in Otago occurs from May-July.

* Stock’s work is undated, but the date is given by Thomson (1922, p. 206).

Stock Importer Date and River of Release No. of Fish* Hodder Provincial Government of Otago 1871, Water of Leith 20 Hodder Provincial Government of Otago 1869, 1870, Waiwera 1 Tweed Otago Acclimatisation Society 1872, Shag 120 Tweed Southland Acclimatisation Society 1875, 1876, Oreti 850 Tweed Southland Acclimatisation Society 1,875, 1876, Wyndham 250 Tweed Canterbury Acclimatisation Society Ova failed to hatch Tweed (1876) Otago Acclimatisation Society Howietoun Johnson ■ —

Table I.—RELEASES OF SEA TROUT IN NEW ZEALAND.

Arthur, 1881 Yarrell, 1836 p. 40 Parnell, 1838, p. 293 Houghton* 1879, p. 95 Seeley, Day, 1886, p. 310 1887, p. 157 Dorsal surface and sides Steel gray with blue tints Bluish black Bluish black Dark bluish Blackish, purplish tinge on sides Bluish gray, lighter on sides Ventral surface White White White Silvery white Silvery white — Spots on body Black, Black, Black, Black, Black, Black, cruciform cruciform cruciform cruciform cruciform cruciform Dorsal fin Bluish black Bluish black Dusky Bluish black — Light gray Adipose fin Bluish black — Dark Blackish — Caudal fin Bluish black — Dusky Bluish black Blackish Gray or dark coloured Pectoral fin White with blue black streaks Bluish white Inner surface dusky Blue gray Inner surface blackish, outer colourless Bluish lilac Pelvic fin White White White White Inner surface blackish, outer colourless Anal fin White with light bluish streaks White White White

Table II.—COMPARISON OF COLOURATION OF TROUT TAKEN FROM OTAGO HARBOUR, 27TH APRIL, 1880, WITH PUBLISHED DESCRIPTIONS OF SALMO TRUTTA.