NATURE NOTES.

Otago Witness, Issue 3215, 27 October 1915, Page 65

NATURE NOTES.

By G. M. Thomson, F.L.S

No. XXXVT.—NATURALISATION OF ANIMALS (Continued).

In my last notes I mentioned the fact that the first brown trout in New Zealand came from Tasmania. It would he more correct to say that all the brown trout in this country came from Tasmania. The Otago Society sent Mr Clifford across in November, 1868, and he brought back ova, from which nearly 800 fry were hatched ; in 1869 1000 were obtained, and in 1870 1070 fry. They were quickly spread all over the country, and they increased in size at a phenomenal rate. Fishermen arc proverbially noted for their modesty of assertion; therefore the following statement from the eighteenth annual report of the Otago Acclimatisation Society will be read with interest;—“Enormous Fish Reported : One taken out of Lake Hayes is said to have been 601 b in weight; two seen in the Clutha River, below the mouth of the Lindis, were estimated at 801 b each; one from the Mararoa River weighed 421 b. As no Salmo fario over 301 h seems ever to have been taken in English waters, the above weights must at present be received with caution.” After these interesting surmises we may come back to a record of simple fact—viz., that from 1869 to the end of 1-914 the Otago Society liberated over 22.000,000 young fish in the streams of this provincial district. The Wellington Society between 1902 and 1915 liberated and sold over 6,000,000 fry; but I have no complete records yet from any other society. The only other society which imported brown trout ova from Tasmania was the Auckland one, which obtained 1000 eggs in 1870; but only 60 fry hatched out. Further supplies were got in 1872. 1873, and 1874; but no record of their number is now obtainable. From these shipments a very large proportion of the brown trout in the North Island was derived. The rainbow trout (Salmo iridens) were originally introduced by the Auckland Society, which imported the first lot of ova in 1883. Mr Cheeseman savs: “ I believe that the whole of the wild stock of rainbow trout in New Zealand has been derived from the Auckland Society’s introductions.” Unfortunately, I have not yet received the later reports of this society, and so cannot record the enormous number of fry and ova which it has distributed over the country. But the 'Wellington Society, trtw on 1901 and 1915. liberated and sold over 2.730,000 fish, and the Otago Society in the same period some 513,000. Another species which has been verv widely distributed is the American brook trout (Salmo fontinalis), which was first introduced to Auckland in 1877. Again I cannot tell how many millions of fish the Auckland Society liberated or distributed ; but the Wellington Societv has distributed over 660 000 fish, and the Otago Society over SCO,OOO. Since 1890 the Government and the Acclimatisation Societies have poured out money lavishly in attempts to natur - ’ 1 the Atlantic salmon (Salmo salar) in this countrv. Ova have been introduced by the'million, and the young fish have been turned out in many rivers. Both Otago and Canterbury kept fish in the ponds, and obtained ova from them, liberating the fry in various streams; bpt once the fi h went to sea they were never heard of again. I have not got the numbers of eggs which were introduced, nor of fry hatched out from these ; but no authentic record occurs of the capture of a returned fish. The Otago Society, in its report of 1900-01, states; “We have assurance of an old experienced salmon-fisher, Baron Bultzingslowens, who visited our shores during the last fishing season, that he caught a true grilse”—i.e., a young salmon) —“ in the Waiau last February. He savs ‘ the main object of these lines is to tell you that one of the 41b fi=h was a true grilse, and not a trout. I am too old a salmon fisherman, and have landed too many hundreds of grilse and salmon, not to know* the difference between a grilse and any kind of trout. There is to me not a shadow of doubt about that fish being a true grilse. Had it been possible to send vou the fish I should have done so.’ ” The Field of January 9. 1892, in an article on “ New Zealand’ Salmonida?.,” states that Mr Tanner, bon. secretary of the Southland Acclimatisation Society, “sent three frozen fish from the Aparima River, supposed to be from the salmon fry liberated there in 1890. They were from to 21b in weight. They’ were submitted to Dr Gunther, who reported as follows: “These specimens are most assuredly not salmon (S. salar) ; neither are they brook trout (S. fario). They are a kind of seatrout (S. trutta), looking extremely like the Irish white trout. But the different kinds of migratory sea-tront are so closely allied to each other that it is almost a matter of impossibility to give an opinion on artificially-reared fish or their offspring.” Tire paper goes on to say: “This leaves the question precisely where it was, ard will confirm the opinion of those who

insist that the acclimatised trout in Tasmanian and New Zealand waters acquire a distinct character of their own,” In 1896 a fish was caught in Oamaru Harbour which was sent to the editor of the Field by the Waitakl Acclimatisation Society. This was submitted to Mr A. Boulenger, of the Natural History Museum, South Kensington, and stated by him to be a true Salmo salar. It was between 81b and 91b in weight. The angling editor of the Field commented as follows on this fish: —“I have examined dozens and scores of frozen fish sent from New Zealand as salmon, which, in spite of their size and appearance, were trout of some kind. This is the first of these forwarded specimens which has been, to my mind, thoroughly satisfactory, and which, from a superficial inspection, would lead one to say with confidence, ‘This is a salmon.’ ” Some wise critics think that the fish should have been placed in one river, some in another, and attribute failure to this cause. Well, it is interesting to know that in the first instance ova were procured in the Old Country from the following rivers:—Spey, Tay, Forth, and Tweed, in Scotland; from the Tyne, Ribb'.e, Hodder, Lane, Avon, and Dart, in England, and from the Rhine. In this country they have been liberated in all sorts of rivers—the Aparima, Mataura, Owaka, Clutha, Leith, Waitaki, nearly every stream on the Canterbury Plains from Temuka to the Clarence, on the West Coast from Lake Ada, in Milford Sound, right up to the northern end. In the North Island, in several streams from Wellington to Taranaki. Yet in all the record is the same. The fish grow to 10 or 12 inches in length, go down to the sea and never return. All sorts of theories have been advanced to account for this fact. One idea is that they are all eaten, which is nonsense in face of the fact that brown treat and Californian salmon also go to sea, but never fail to return to the rivers, though not necessarily to the same river as they were hatched out in. Some think the sea is too hot and some that it is too cold, some accuse the nor’-easterly current on the Otago coast for carrying them out to sea, hut none accuse the nor’-westerly current on the West Coast of bring them back to the rivers. The fact is that their disappearance is a mystery, and at present there are no data on which to found a reasonable explanation. Probably the only way to get the required information would be to attach small labels to marked fish, and endeavour to trace these. Then it might be possible to ascertain what comes of the myriads of fish which we from time to time send out from these shores. It is interesting to read what Mr Saville Kent, the Queensland Commissioner of Fisheries, said in 1872 : —‘‘The attempts to stock Tasmanian streams with the true salmon have utterly failed. The young fish have thriven magnificently until their departure for the sea as sniolts, at which stage they have simply vanished from human sight, the warm seas of the south being too enervating for them.” This last explanation is quite incorrect: the seas on the coasts of Britain and Norway are on the average warmer than the seas on the southern coasts of Tasmania and New Zealand. Therefore the explanation must be sought elsewhere. While the introduction of the Atlantic salmon has been sc complete a failure, that of the Californian species (Salmo quinnat) has been a great success. The Auckland Society got large consignments of ova in 1875 and 1876. and liberated over 20,000 fry in various rivers—the Waikato, Thames, Whakatane. etc. The Canterbury Society also got 100,000 ova in 1876, and over 50,000 in the following year, and these were turned out in many of the streams both north and south of Christchurch. The Auckland Society got 100.000 in 1877, and the same number in 1878, while in the same years the Otago Society liberated 13,000 in the Kakanui River and 18,000 in the Waipahi. The Wellington Society also liberated numbers of fry in the Hutt River. Out of all these fish only one example was recorded and identified as a Californian salmon. This was a specimen found dead in the Avon in 1884, which was sent to Dr Bean, ichthyologist of the U.S. Museum, Washington. With this exception it looked as if all the attempts made had failed. Curiously enough the Americans themselves had the same experience with quinnat salmon. Marshall M'Donald, Commissioner of the CCS. Department of Fish and Fisheries in Washington, writing to Mr Hugh Craig, of San Francisco, said:—‘‘We have experienced the same difficulty in attempting the acclimatistion of this species upon our eastern coasts; all experiments having failed completely after expending a large amount of money, and being tried on a scale of magnitude and under a variety of conditions sufficient to test fully the capabilities of our eastern streams in this direction. We have attributed the failure to the different temperature conditions prevailing in the rivers of the east and west coast at the spawning season, which is from July to September. The streams of the west coast at this period, fed as they are by the melting snows in the mountains at the head of the large rivers, ' present ?„ relatively low temperature, which invites the ascent of the salmon in obedience to the natural instinct which pervades the entire family to move from warmer to colder waters in seeking- their spawning grounds. On the east coast at this season of the year our rivers are warmer than the adjacent seas, and we have concluded therefore that the failure to enter our streams is due to the higher temperature conditions prevailing in them. This is probably true in regal’d to our own waters. The summer temperature of the Pacific coast streams in which the salmon enter at the season of spawning rarely reaches 60deg Fahr. During the same season on our eastern coast the temperature rises to at least 70deg Fahr., and sometimes reaches a, maximum of 80deg to 85deg.” In 1901 the Government imported 500.000 ova, and hatched them at Hnka-

taramea, where a number were liberated into the Waitaki, while others were put in Lake Ohau. Whether it is from these fish or from those previously liberated I cannot say, but quinnat salmon are now met -with in several of the Canterbury rivers, and they run regularly up the Waitaki, so that great numbers oi eggs are now secured from them, and are hatched out at Hakataramea. This is one of the most successful of the attempts naturalisation.