Using sclerite number distribution in marginal growth of scale for ageing sea trout spawners (Salmo trutta morpha trutta L.) from the Vistula River

Abstract

Distribution of sclerite numbers in marginal scale growth of A.1+, A.2+ pattern in sea trout spawners was analysed. Two distinct peaks of sclerite numbers were obtained. Two phases of growth were distinguished: small marginal growth and big marginal growth, used as a basis of age determination in sea trout spawners. Probability of error in trout ageing was calculated for the area where the distribution curves overlapped.