Radio transmitters to reveal the secrets of sea trout

Sea trout are highly regarded among anglers, and thanks to intensive fisheries conservation efforts they have become increasingly common. The trout reproduce in small rivers along the whole of the Swedish coast, and the eggs hatch in the spring. The fish then remain in the river for about two years before migrating out to sea.

"The environmental requirements of trout and their behaviour in the rivers where they are born have been studied for several decades, but we know very little about their adult lives at sea. With the aid of radio transmitters, we hope to be able to analyse how sea trout migrate and in what environments they move," says Johan Höjesjö at the Department of Zoology of the University of Gothenburg.

Knowledge of how local populations of sea trout mix in the sea is also lacking. It is important to be able to locate different populations and their spread from the point of view of fisheries conservation. The researchers will therefore also be studying the genetic kinship of trout along the coast. To obtain as broad a basis as possible, anglers along the west coast are being asked for the assistance in collecting fin samples.

"What we need is a piece of a fin, preferably the pectoral fin, around 5 x 5 millimetres, together with information on where the fish was caught and its size. It's fine to send the piece of fin taped onto a piece of paper in a franked envelope. A photograph would also be appreciated," says Höjesjö.

The fin samples should be sent to: Department of Zoology, University of Gothenburg, att: Johan Höjesjö, Medicinaregatan 18, 413 90 Gothenburg

Everyone who takes part in the study and gives the researchers their e-mail address will receive information about the results by e-mail.

The project is being directed by the University of Gothenburg is taking place in close cooperation with the Swedish Board of Fisheries, the Swedish Angling and Fish Conservation Association and several coastal municipalities.