FISH RESEARCH

Timaru Herald, Volume CXXXVIII, Issue 19987, 20 December 1934, Page 10

FISH RESEARCH

TALK TO ANGLERS’ CLUB

PROFESSOR PERCIVAL’S VISIT

Much interesting information regarding the culture of fish and their habits was given members of the South Canterbury Anglers’ Club last night by Professor Percival, of the Fish Research Committee. There was a large gathering of anglers over whom Mr T. O. Fox presided. In int?-oducing Professor Percival. Mr Fox emphasised the important part scientific research had played in all departments of civilisation and said that, while a good deal of time and money w r ere spent on research which proved useless, the results which had been obtained represented a handsome dividend for the expenditure. Anglers owed a great deal to Professor Percival for the time he spent in their interests. Professor Percival said the Research Committee was set up in 1929 to investigate the well-being of fish in New Zealand w'aters. At that time, the sum total of information regarding trout in New Zealand was contained in five or six papers published many years ago, so it was apparent that the committee’s scope was very divergent. The first task was to study the history of fishing in New Zealand and in that direction considerable difficulty had been encountered, but records taken of fishing in a four mile stretch of the Oreti River showed that the decline in fish was due to an increase of anglers, an increase of motor traffic and increased speed of transport. It was found that there was an over-supply of feed in 'most New Zealand rivers, more so in some than in others. There had been no apparent deleterious effect on fish growth. Certain investigators had said that the clearing of bush had caused a shortage in fly foods and also a greater run-off which, it was held, had caused a decline in snail and slug growth. Professor Percival said that his own researches showed that that was not so, and in fact that grasscovered ground provided a better runoff to a stream than bush country. “We have come to the conclusion that the fish’s greatest enemy is the angler,” remarked the speaker. Average Spawning Age The examination of scales by the South Canterbury Aclimatisation Society’s ranger (Mr F. W. Pellett) was referred to by Professor Percival, who said that results showed that there was a great variation in length and weight of fish taken from different parts of the country. The average age of spawning fish taken from the Selwyn was five years, from the lower Rangitata four and a half, from the Oreti about three years. It was interesting that in waters where the average age was low fish were easy to catch and, conversely, in waters where the average age was high fish were harder to catch. The further down one went, the older the fish became. So it was that in the upper reaches of a river one found small fish, growing larger until large fish were found in the estuaries. Referring to a contention that quinnat were responsible for driving out the brown trout, Prof. Percival said that for two years a man had been carrying on research in Canterbury, and he had come to the conclusion that the quinnat, brown and rainbow, in their early stages of growth, lived as harmoniously as did any fish of the same species. He also found that by hand stripping one lost 11 per cent, of eggs, and that one could gain a further three per cent, by so damaging the fish that they would die. Any egg collector should be satisfied if his loss was restricted to 10 per cent. After discussing spawning, the speaker said that if it were found that a stream was good for spawning and a majority of eggs in it survived then it was little use a society stocking up that stream. On the other hand, if the stream had a low survival rate, then the angler would benefit if fish were liberated there. It was said the committee was not in favour of hatcheries, but the committee’s only interest was the well-being of trout. They were working to find out things, and if the committee had stopped all the barren theorising which had gone on, then the money had been well spent. “I would like to see the hatcheries in the South Island shut down for

three to five years, or certain streams left for that period to study regeneration,” said the Professor. “Suppose you did not stock the Opihi for a year, and studied the age groups by marked scales. You would find that the fish you were catching belonged to certain groups, and if you caught no fish of the 1935 group in 1938 you would know that they were not there because they had not been put there. On the other hand, knowing that you had put no fish in the river in 1935, you caught fish which belonged to that age group you would realise that those fish had been hatched on the spot. Then you would know that there was no need to stock the river.” Professor Percival said he was endeavouring to persuade one of the South Island Societies to do that and said he would be glad of the co-operation of the South Canterbury Society. After illustrating his remarks with slides. Professor Percival answered a number of questions, and was accorded a vote of thanks. A vote of thanks was also accorded Mr J. Palliser for lending and operating the baloptican.