TROUT-BREEDING.

Dominion, Volume 3, Issue 795, 19 April 1910, Page 3

TROUT-BREEDING.

ZEALAND'S LESSONS. The statement that trout ova from New Zealand are to be secured for Blaedon .Reservoir (says the "Sporting and Dramatic New,s" of February 24), where already trout grow big, is something that would have made the late 'Frank Buckland wonder and rejoice. Little did he guess when he fathered the erpbrt o£ trout ova for New Zealand that the experiment would result in the finest trout m the world (unless Tasmanian fish exceed). It was not dreamt that the wonderful results accomplished in the southern hemisphere would eventuate in. improvement such as to induce Englishmen to reimport with a viow to increased size of the Home stock. What is wanted is not only large trout (those we have), but large trout in numbers, and a race that are free to feed on fly and grow large generally. What chances are there that all these qualities will survive the loss of Now Zealand's conditions? It is not very easy to say what those conditions are to the trout, v but one thing that is very evident is that tho food supply must be unlimited. It must be so now; but, more, it must have been so during the whole time that the race of trout has been improving because of it. Will the offspring of these fish continue to grow large where their collateral relations have not done so? It seems likely that the conditions that served their ancestors to make them small will again dominate the situation, and no doubt in time that will be so, unless English people become learned, not so much in the art of fish culture as in the culture of the natural food of the fishes. That is by no manner of means impossible, but it is both an art' in breeding and a science in what to breed. Both, are at present almost absolutely neglected, and those fish culturists who know the way are not always willing to advocate a policy that would, if generally adopted, go to destroy their own monopoly. In other words, if riverside owners were to attend to the cultivation of food, their trout woald taKe care of themselves. That is not to say a race of dwarfs, by eating much, can became giants in their own generation, but. they can improve, and each generation will grow bigger and better. Probably the better.! feeding would be very much thrown away on the raco of dwarfs, and therefore it may be wise, whure impioved feeding conditions exist, to go tor a race of giants in the first instance, and try to improve that race instead of the dwarfs. We are not hopeless about results, for even in poor feeding waters there must be very much, in breed. To grow big, a race of- fish' must be frco feeders, and who is the .fisherman who has not had cause to lament, that British trout have bad appetites. It. is born in them.

' Obviously, all future' improvement of numbers and size of British trout turns on food, and it is curious to observe how rough and ready are the means employed to that end. It was discovered, thirty years ago, that if dry land and vegetation were submerged, as when the Liverpool .waterworks submerged the boglands on which now is their Welsh reservoir, the trout at once grew big. Obviously decaying vegetation was the source of nutriment to some creatures on which the trout fed. Blagdon followed with similar methods, and results in big fish; and Loch More, in Caithness, has only recently shared improvement by-having its area extended over rhe heather and grass adjoining its former shores. This lastnamed is the most important experiment of all, for although already it has become a famed trout lake, there is still the question of its 6almon, and those of the Thurso (which flows through it) to be solved. Its trout improvement would be a sorry reward for any damage to the famous Thurso as a spring salmon river. Thus, all thai is known and acted upon is that "somehow" land vegetation under water is good for trout. What particular kinds of water insects are most improved by such treatment is not known, nor Which are the most use to trout. But possibly it is not the decaying vegetation as food so much as the harbour it gives to insects where they may breed in poace that is the secret of the .success. Turf roots are a network of fibre, so also are heather roots; no fish could get into either, but insects of the land breed in those recesses, out of harm's way, and possibly, when submerged, insects of the water do so also. Some sucoess in improving fish has been achieved by no greater labour that tying up, bundles o£ useless ferns and sinking them. ■ These formed- nurseries for water insects, which Wrod in multitudes in them, so that only those that left tho nurseries were eaten by the trout, whereas had those bundles not been there, the breeders amongst the insects would have been oaten also. It is remarkable that althongh nobody believes that fish feed on water, most of the preservers of rivers (outside fish culture establishments) act as if they thought good wator was all fish required.