Record salmon hatchings

Press, Volume CXII, Issue 32959, 4 July 1972, Page 14

Record salmon hatchings

Records in salmon raising have been set during the last year by the North Canterbury Acclimatisation Society. Requests from other scientists reached a record figure, and 273,000 salmon have been raised at the society’s hatcheries at Silverstream.

Working through the South Island Salmon Committee, the society has received orders from the Internal Affairs Department and the Ashburton and Otago acclimatisation societies. These orders will be repeated for the next four or five years. The fish will be used to supplement runs in present salmon waters, and in an attempt to introduce salmon to other rivers. GROWING INTEREST

Societies throughout the South Island were conscious of the growing interest in salmon and of the increasing demands likely to be placed on salmon stocks. For this reason they were keen to build stocks as rapidly as possible, said the secretary of the North Canterbury Acclimatisation Society (Mr H. B. Barker) yesterday. Irrigation was one of the main dangers facing salmon stocks in South Island waters, he said. Irrigation not only reduced the amount of water in rivers —and if there was no water, there could be no fish—but

irrigation intakes could siphon small salmon from rivers, killing many young fish.

hatching, Mr Barker said. As far as was known, as they headed for the sea. salmon tended to hug the banks of rivers. Generally, irrigation water was drawn from the river edges. BARRIERS URGED One irrigation pump could destroy several thousand young salmon within hours, but fish barriers could avoid much or all of this loss. Acclimatisation societies were pressing strongly for adequate and effective fish bar-’

riers to be installed at the intakes of all irrigation schemes, Mr Barker said. The other problem was more difficult. Demands for irrigation were rising rapidly, and every scheme drew substantial amounts of water from the river, when the water naturally tended to be low. This plus seasonal lowness could result in rivers falling to a fraction of their original depth, making it much more difficult for salmon to move and to survive. DAMS THREAT

Hydro-electric schemes were another threat to salmon, Mr Barker said. A

big dam was a very substantial barrier and large, expensive salmon ladders were needed if fish were to be able to pass the dam to their spawning grounds. If there was no adequate ladder, natural spawning runs were interrupted, seriously affecting the return runs of mature fish to the same river in later years. Natural losses occurred, too —a fresh in the headwaters of a spawning river at the wrong time could destroy marfy salmon ova.

Acclimatisation societies had a statutory duty to protect stocks of wild fish, and at the moment they were considering the best way in which New Zealand waters could be used both for recreation and agriculture, Mr Barker said. The aim was to have water available for all uses without any one use being at the expense of others.

Salmon, like other wild fish, were one of this country’s important natural resources, providing sport and recreation for New Zealanders and overseas visitors, Mr Barker said. As tourism and the amount of leisure time increased, the demand on salmon stocks was also likely to rise rapidly. Protection now was essential.