Andrzej Kompowski and Zbigniew Neja
University of Agriculture in Szczecin, Kazimierza Królewicza 3-4, 71-550 Szczecin, Poland

Key words: Aspius aspius, asp, fecundity, gonadosomatic index (GSI), Międzyodrze.

Abstract.
The mature section of the asp population in the Międzyodrze waters is comprised primarily of individuals ranging in age from five to seven years. The proportion of mature males to mature females is nearly 1:1. The absolute fecundity of asp ranges from 63 044 to 324 833 eggs. The dependence of absolute fecundity on female length and weight was nearly linear. Absolute fecundity also increased with the age of the fish, although this correlation was much weaker. Relative fecundity was in the range of 35.11-107.94 eggs per g of female body (without viscera). No significant correlation was confirmed between relative fecundity and the length, weight or age of the investigated asp.