Over 100 pike and bream are being operated on with small transmitters outside Östhammar as part of a research project to improve water quality in Granfjärden.
For two weeks researchers have been working in the coastal bay Granfjärden. The fish are anesthetized, fitted with transmitters in the abdomen and released again.
The aim is to understand how fish movements affect fish numbers and water quality. Since last year reduction fishing has been carried out to lower numbers of roach and bream that stir up sediment.
"We want to reduce the amount of roach and bream because they contribute to making the water cloudy", says Örjan Östman. The project is led by the Swedish University of Agricultural Sciences together with Östhammar municipality and the company Klara Vatten.