Fecundity of river lamprey Lampetra fluviatilis (L.) in Drwęca River (Vistula Basin, Northern Poland)

Abstract

Fecundity of river lamprey (L. fluviatilis) of autumn and spring run to Drwęca River was studied. The population showed very high fecundity (23460-52072 eggs) related to large individual size of Drwęca lampreys, bigger than in other European rivers. No statistically significant differences were observed between autumn and spring run.