PHENOGENETIC ANALYSIS OF THE POPULATION DYNAMICS OF CRAYFISH ASTACUS ASTACUS L. AFTER INTRODUCTION INTO A NATURAL RESERVOIR

This article presents an overview of the colonization dynamics of crayfish in a reservoir, specifically focusing on Lake Berezno in the Pskov region. The study involved trapping crayfish (Astacus astacus) as representatives of the overall population. To ensure accuracy, certain factors were considered, such as the season of catching, standard fishing gear, bait used, comprehensive morphometric analysis of individuals, and the sex ratio in the population. Based on the data collected in 1998, significant changes were observed in the ecological and genetic state of the crayfish population in Lake Berezno. These changes were possibly influenced by the implementation of a new morphogenetic program aimed at developing the entire useful territory of the lake. Interestingly, the crayfish population did not exhibit size polymorphism, and there was a single morphotype with a Gaussian size distribution. The variation in size observed in the crayfish population is attributed to the trapping methods used, as indicated by the asymmetry and kurtosis of variation. Remarkably, the noble crayfish A. astacus follows similar ecological and genetic patterns observed in other studied aquatic animals. This suggests that crayfish can serve as a reliable biological indicator to assess the state of the aquatic ecosyste