Mark-recapture experiments on fish in Windermere, 1943–1982

Marking experiments on perch, Perca fluviatilis L., pike, Esox lucius L., and charr, Salvelinus alpinus L., have been carried out in Windermere. Numbered tags were used for individual identification, except in some short term experiments on charr. A total of 13 182 perch and 4696 pike were tagged; 2066 charr were tagged subcutaneously and marked with a fin clip. In the short-term experiments 2015 charr were marked with a fin clip or punched hole. Perch were recaptured up to 8 years after tagging, pike 12 years and charr 5 years. Estimates of numbers and mortality were not satisfactory, except for limited sections of the populations of pike and charr. The main reasons for the unsatisfactory results were: for perch, unknown mortality at time of tagging; for pike, selectivity of the gillnets and in some years low numbers tagged; for charr, restriction to few spawning sites and in some places low numbers recaptured. The experiments provided useful information on movements and growth, which could not have been obtained in any other way.