TROUT FOOD

Hokitika Guardian, 18 December 1928, Page 2

TROUT FOOD

SUPPLIES BEING EATEN OUT?

INVESTIGATION IN WELLINGTON

WELLINGTON. Dee. It!

The results of the first year o| the research fellowship for the investigation of the various problems in connexion with trout iile, conducted under tin* auspices of the \ ictoria l niversify College, rendered possible by the gun ran Lee of a throe year’s lellowsltip at CiO(! a year by the Wellington Atc!’matisution Society, arc distuetly encouraging, as shown in the List venr’s reports now available, anil the suggestions made appear valuable. The Research Eellow, Captain J. S. Phillips, deals in his report with rivers in Wellington Province. Me says that lie has 'found not merely that there are bad trout streams, but that fish vary in quality greatly in diflcicnt parts of the same stream. Generally In* attributes the deterioration of lisb in recent years to scarcity of food supply.

•• It is possible that ether food organisms giving improved results might la* introduced into our waters.” states the report. “ For the purpose of (hiding the rate of growth of trout: living oti different organisms, it is proposed to segregate yearlings at Mtistorton, and to feed them with d’fl'erent foods, comparing their rates ol growth, snails being now reared ar tin* hatchery for the purpose.

“For a number of yours trout in hundreds of thousands have been liberated in our rivers, and little thought has been given as to how they are to live*. It is like sending an expeditionary force to a new country and systematically reinforcing them, hut. forgetting to send a quartermas-ter-general and an army sen ice corps. E,, r a time they can live on the country. and in tin* present case they have done so successfully for a long period, hut the aquatic food resources, though rich, are not inexhaustible, and every year the present policy continues the conditions will become worse.

• *As far its 1 can gather, most of tre larger trout are cither up-stream in inaccessible country, where conditions are more nearly as they used to he than in the transformed a ccssiblo areas, or at the river mouths., where food is more varied and pleiitilul (or where the fish may be sea rum, or ill hikes, where, again, the loot! conditions mav hi* quite ilillereiit. *n the accessible and well-lislted portion ol streams ami rivers, there a re. a groat number of small trout —occasional teports Lo the contrary notwithstanding --and in most, though not all. ol these places there is plenty of small lislt loud such its caddis and maylly hit sue and minute gastropods. It is probable that these are insufficient to produce large fish, and it is also probable thatthere are not sufficient of even these to cope with the present policy ol adding 2.000,000 new trout yearly, in addition to those spawned naturally. "'lt would seem highly advisable either to take steps to increase tin* the food supply or to stop putting out fish. ft would he hetetor still to do both. Why not use the hatcheries (enlarged to double the size this 'eat) to rear trout and trout food alternately. or if it is considered preferable use half of them for trout, and half for trout food. As to what food would be most suitable, that will require considerable investigation, and 1 should much appreciate the opportunity ni examining the stomachs ol large fish. Professor Dali! was much impressed with the food value of some Norwegian mollusca. As our only common river gastropod is rather minute, it would probably pay to import something rather larger, but it must be capable of living in swiltly-moving witter. Mr Phillipps, of tbe Dominion Museum, considers that the native fish have been largely eaten out b\ the trout, it would he a simple matter to rear these at the hatchery, Ruliy for example, have been reported spawning at the mouth ol a’stream running into Lake Wairarapa. Tbe number ol whitebait could obviously he greatly increased. provided that conflicting interests could be temporarily appeased. Outlarge Ephernerids are scarce, and they should he increased by importing other large species. Even the most rabid exotophobist could produce no real reason against doing so. It angleis and eel catchers would send stomachs of their catches to me it would prove of the greatest benefit, in investigations, and would show also what proportion of (tel food trout represent.”