Mortality of Pike-Perch (Stizostedion lucioperca, Brown Trout (Salmo trutta) and Landlocked Salmon (Salmo salar m. sebago) Caught as By-Catch in Pelagic Trawling in a Finnish Lake

The post-trawling mortality of pike-perch, brown trout, and landlocked salmon taken as bycatch in vendance trawling in Lake Pyhaselka, eastern Finland, was studied. Exploratory trawl hauls showed that brown trout and salmon were caught only in surface trawling, while pike-perch were also taken in mid-water trawling. Most were smaller than the minimum legal size. When kept in net cages for a week after capture, all salmon died, while less than 15% of the surface-caught pike-perch and brown trout died. Pike-perch caught in mid-water trawling had a much higher mortality than those caught at the surface. Pike-perch and brown trout caught at the surface are likely to recover. Trawling damage to these stocks appears to be minor.