Request for return of tagged salmon

Press, 28 January 1986, Page 29

Request for return of tagged salmon

It is likely that it will be another good season for salmon fishermen, according to the technical officer at the Ministry of Agriculture and Fisheries Research Division, Mr Ron Dougherty. Glenariffe, the research station in the upper reaches of the Rakaia, is still adding tagged salmon to the river.

Since 1977, large numbers of nose-tagged juvenile quinnat salmon have been released each year into several South Island rivers from Ministry of Agriculture and Fisheries facilities and salmon farms.

These releases increase the number of returning adults for the angler to catch, but these releases are also part of a scientific study of salmon. Fariy research at Glenariffe was into the basic biology of the fish and the character of its life history. Growth rates, age structure, and fry production were determined. At present, the main research aim is to determine how to obtain the maximum adult return from the number of juveniles released, which will benefit both the angler and salmon farmer. The project, which has been going for about 20

years, was begun because it was thought that the Rakaia should carry many more adult salmon than it did.

As part of the study, juveniles are released at different times and sizes.

Various factors come into play in determining how well the juveniles survive — their size and muscular development affects'to what degree they are carried by the current.

The length of the river also has an effect; it is only 80km from Glenariffe to the sea but North American rivers can be up to 1300 km long, thus giving the fish more of an opportunity to grow. “In our study we work with other groups such as catchment boards and acclimatisation societies but it is important for fishermen to play their part as well,” said Mr Dougherty.

“We must have the heads of tagged salmon returned to us to make our statistics as accurate as possible,” he said. The tagged salmon have a one millimetre tag implanted in their head before they are released. A tagged salmon is identifiable by the absence of its adipose fin. "If a fisherman catches

a salmon without an adipose fin he should remove the head and hand it into the nearest head depot,” said Mr Dougherty.

There are over 50 head depots near South Island rivers. “Fishermen can also help when they are in the company of other people fishing. Visitors from overseas or even the North Island may not realise the significance of the missing adipose fin,” said Mr Dougherty.

“Someone who has never caught a salmon before may not even notice that a fin is missing,” he said. “So it would be helpful if fishermen made such people aware.” Mr Dougherty said that anyone with a fish head could bring it to their lab and see the head being processed. If the salmon head returned has a tag, the name of the angler is entered into a draw and has a chance of winning $5OO. Tagged salmon caught at sea entitles the angler to a $5 reward and a chance in the draw. For anyone interested in salmon and research into salmon, the Glenariffe research station will be open to the public over Anzac week-end.