Art. XXII.—Notes on the New Zealand Sprat.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 15, 1882, Page 203

Art. XXII.—Notes on the New Zealand Sprat. By W. Arthur, C.E. [Read before the Otago Institute, 15th August, 1882.] Plate XXXIV., fig. 1. This fish has been described by Dr. Hector in the appendix to his Catalogue of New Zealand Fishes, and was subsequently figured (Trans. N.Z. Inst., vol. v., pl. xii.); but, as it appears on our coasts at considerable intervals of time only, I deem it may be useful for reference to record its recent reappearance accompanied by a drawing of the form found in our waters, and a description sufficient to establish its identity. The specimen which I have figured, and will call No. 1, is a male sprat, taken in the sea at Oamaru in May, 1882, out of a large shoal which came in to the coast at that date. The body is compressed laterally, dorsal outline slightly arched, abdominal deeply curved; head one-fifth total length; maxillary curved, with posterior extremity rounded accurately, posterior half of bone free, disconnected from head and quite transparent in colour, does not project beyond vertical from anterior margin of orbit; mouth small and round, lower jaw very prominent and projecting beyond intermaxillary one-tenth of an inch when mouth open as in figure. Operculum nearly vertical in outline but sinuous, preoperculum with a distinct lower limb, no striæ. One dorsal fin, caudal forked, belly-fins very fine, origin of dorsal and ventral fins in same vertical line. Lateral line barely visible, abdominal serrature not very prominent, but fourteen bars mark the space very distinctly between pectoral and ventral fins, apparently the external impression of the hæmal spines. Scales cycloidal, large, and deciduous.

Eye very large and round, iris yellow, pupil bluish-black. In colour the back is of an indigo hue shaded down into the brilliant silvery sheen of the sides and belly; dorsal and caudal fins dark; pectoral, ventral, and anal fins light olive yellow. Dimensions.—Total length, 4 9/10 in.; depth, 19/20; head 1 1/10; eye, 26/100; least depth of tail, 4/10. Fin rays.—D, 16; P, 18; V, 9; A, 22; C, 21–4/6; longest ray, 15/20; shortest, 6/20 in. Lenyth of fins.—D, 11/20; P, 7/10; V, 4/10; A, 13/20 in. Branchiostegal rays, 6. Scales.—L. lat. 55; L. trans. 15. Teeth.—The teeth in this specimen were scarcely perceptible to the touch and very minute. On examining the viscera, I found a thin silvery lobe 2 inches long, which I take to be the air-bladder. It was remarkably like the lobe of the Scotch herring, but the fish was rather old when opened. Specimen No. 2.—This is a female from the same locality as the male and obtained at the same time. Dimensions.—Total length, 4 7/10 in.; depth, 85/100; head, 9/10. Fin rays.—D, 18; P, 17; V, 8; A, 17 (injured); C, 22–4/4. Branchiostegal rays, 6. Vertebrœ, 56. Teeth.—Very minute, but perceptible to touch on mandible, intermaxillary, and tongue. Under the microscope four or five teeth were plainly seen on the intermaxillary, with some rudimentary ones. On mandible a few were seen very distinctly, one of the largest being a perfect cone, broad at base, clear and transparent, and about 1/3000 of an inch long. I also could make out six or seven others on same bone, but not so shapely and of irregular sizes. The ova of this female, in two lobes each 1½ inch long, were well developed. So light were they that in placing one lobe into fresh water it floated, and sunk very slowly when wetted all over its surface afterwards. No individual ovum was visible to the unassisted eye, but under the microscope the ova appeared to have an irregular pentagonal outline, covering an interior circular core full of cells. The space between core and outer covering also held some cells, but not so closely packed as in the core, while all the ova were surrounded by a jelly-like mass of fluid full of free cells. The diameter of each egg was about the 1/1550 part of an inch. Ova of Clupea sprattus × 1550. This beautiful little silvery fish is mentioned by Dr. Hector as having been found in Foveaux Straits and near Wellington in 1872 (see Cat. N.Z. Fishes, p. 133). A fishmonger in Dunedin remembers it being in the

market about eight years ago, so probably he means or refers to the same date as above, although he could not tell me very exactly the time of the occurrence. Neither can I find that this herring has been again seen on our coasts till May of this year, when it appeared in large numbers for a short time, as I have said, at Oamaru, close inshore, about a fortnight altogether; then bad weather set in, and it has not been heard of since. The shoals did not visit Moeraki Bay, nor Dunedin Harbour, but those fish caught were sent to Dunedin, and were found to possess good edible qualities. As to the habits, reproduction, and growth of this fish we know less than the little which is known of the British herring. Possibly, however, the sealers and whalers, still living, may possess information which would be of great interest in elucidating its natural history. Meantime one circumstance may fairly be inferred from the minuteness and buoyancy of the ova, which is, that in whatever depth of water spawning may take place, the hatching will occur on the surface of the sea in all probability. I have made a rough calculation from the size of the roe-lobes and find that one of these fish will contain over 20,000,000 ova! This is an almost incredible number, and would require verification by an examination of a number of other individuals when an opportunity again occurs. I may mention, however, that Mr. Frank Buckland, in his Natural History of British Fishes, gives approximations to the above number in the roes of the turbot and conger eel, which are given at 14,000,000 and 15,000,000 eggs respectively. The great number of ova in this sprat is suggestive of a very heavy death rate due to this species of herring being probably the food of the seal, whale, and predatory fishes, as well as of marine birds. The fact of these fish visiting our coasts at considerable intervals of time, points to another circumstance which may regulate their movements. Dr. Parnell in his “Fishes of the Forth,” describes the British form of the sprat as being very sensitive to cold, and that on the approach of winter it ascends the estuary of the Forth to the brackish water in search of a warmer locality. An old theory was also held by Pennant that the herring migrated to the arctic seas before winter. While there is much evidence of the presence of herring on the British coasts during winter, there is nothing against the probability of some of the species absenting themselves in the direction indicated at that time of the year. Be that as it may, if our sprat is as sensitive as its British representative, a reason would exist for its migration from more northern waters to the antarctic seas after our summer is past. For a warm current is believed to flow from the tropical region of the Pacific

Ocean towards the south pole, but which is separated from the east coast of Otago by a cold northerly littoral current. As the boundaries of these currents fluctuate a good deal according to the season and direction of the winds, a deviation of the warm southerly stream towards Otago at the time of the migration of the sprat would account for their occasional appearance as well as their disappearance. At present, however, there is not much more known of the great currents of the South Pacific Ocean, than of the habits of this little herring itself. Note. Since the above was read, a good deal of interesting information not previously ascertained by me, has been kindly placed at my disposal relative to above species. It is from Mr. P. F. Stoddart and Mr. Cosgrove. Mr. Stoddart says: “For years prior to 1875, when I was living near Moeraki, the sprat visited the Fish Reef regularly from March till May in incredible numbers, which were easily seen by us while fishing there, as they came close under our boat. They always disappeared on the approach of cold weather. The red cod which we caught on the reef were often found to be stuffed full of sprats,—indeed they were sticking out of their mouths.” The Fish Reef lies about three miles off shore. In a subsequent letter from the same gentleman, he adds:—“I have made enquiries about the sprats. Captain Liddle (who has been fishing at Moeraki for the last fifteen years) says, they are there every year in any quantity, about the reefs a mile from the shore. They begin to appear about January, but are most plentiful in March and April. On two occasions during that period they came inshore, into Moeraki Bay, in dense masses, as they did also at Oamaru and Timaru. He could give me no information which way the shoal travels, as they seem to be all over the sea; and accounts for their going close inshore, sometimes in dense masses, to other fish pursuing them. “Mr. Leggatt, who used to have the landing service at Port Moeraki and is now in Christchurch, also knows the fish very well and remembers his boys getting buckets full, left among the holes in the rocks by the ebb-tide, some four or five years ago. Captain Liddle says, that with a hoop-net, which he sinks a few feet at the stern of the boat and then throwing over some food, he can catch any quantity any year. There were plenty at Moeraki at the same time (May, 1882) these shoals were in Oamaru Bay, but they did not come close in the same.” Mr. Cosgrove writes me:—“It makes its appearance on the east coast of the Otago Peninsula in the month of November and remains off the coast of the South Island throughout the season, which is, so far as I can gather from searching enquiries and from personal observation, from

November to end of March. When first seen the shoal is usually travelling southward; still this is not invariably the case, as I have on one or two occasions seen it head towards the north. The direction in which the shoal is moving can at any time be ascertained by watching the movements of the mutton-birds (Puffinus tristis). These birds follow the shoals in vast numbers, indeed I might say, in myriads. So great are their numbers that I have seen a portion of the surface of the water, several square acres in extent, literally black with them. “The shoals pass and repass the coast between Ocean Beach and Sandfly Bay several times during the season, at a distance of from a quarter of a mile to two miles from the shore, according to the state of the weather. Should the sea be very calm, with a gentle breeze from the land, they are almost sure to come inshore. “For many years in succession they came in at Sandfly Bay, a beautiful spot at the foot of Mr. W. Robertson's property; but they have only twice visited that harbour during the last five years. When, however, the sprats do come in, either at this place or any other place along the coast, they come so close that all the pools around are actually packed with them, and when the tide ebbs the silvery little creatures may be seen turning over on their backs in thousands dying from want of oxygen. “Mr. W. Robertson informs me that the shoals have passed Sandfly every year since he settled there in 1860, and that in 1881 a shoal came in for a few minutes but went out again, and passed on towards the south. “The shoals are sometimes followed by great numbers of red cod, barracouta, groper, and dogfish, and these again are followed by seals. When such is the case, the scene from the shore baffles description. On the outside of the shoal are terns, gulls, and mutton-birds, fighting and screaming over their prey; while beneath are the large fish above-mentioned driving the sprats towards the surface; and added to the noise of birds and fish you hear the sudden splash and short bark of some three or four seals. So pressed have I seen a shoal, that several square yards of the fish were raised quite out of the water by the efforts of the sprats at the bottom to get out of the way of their enemies' attacks from below. On one of these occasions I caught six large dogfish by means of a large hook lashed to a long rod. As these fish lay struggling on the rocks, sprats came sliding and even jumping out of their mouths in great numbers! “As an article of food the sprats are really excellent. When fried in olive oil they are deemed a luxury by the most epicurean. As to how they could be caught for market, when offshore, I dare not venture an opinion; but when they are inshore, I can with confidence affirm, that they could be caught in great quantities with hand-nets alone. Indeed, so numerous are

they at these times, that a man standing on the rocks could lift them out of the shoal with a shovel. There are many other interesting facts which I have not mentioned here, but as you may already be wearied I will conclude, hoping you may be able, from these rough notes, to glean such information as you require.” My enquiries, before writing above paper, being confined to the fishmongers in Dunedin—is the explanation of the difference as to the appearance of this fish on the coast between my opening remarks and the notes just added. But the times known only to the fishmongers, are no doubt those when these fish come or are driven very close inshore. As the great body keep seemingly well out from the beach, and as an article of food this herring is very good, it ought to be searched for and netted by the fishingboats of our new Deep Sea Fishing Company.