The features of narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) population development in Lake Sevan during 1996–2018

Abstract

The narrow-clawed crayfish, an invasive hydrobiont of Lake Sevan appeared in the lake due to accidental introduction having occupied almost the entire territory of Lake Sevan, finding favorable conditions for its existence. Investigation of the dynamics of narrow-clawed crayfish population development showed that since 2014 there has been a tendency in reduction of the crayfish population, which was the result of improper organization of the fishing process and deterioration of the ecosystem. Although the main factors limiting the distribution of crayfish in natural conditions are oxygen deficiency at great depths and the type of the bottom sediments, in recent years, the reason for reducing the stocks of narrow-clawed crayfish is the increased anthropogenic impact, in particular, the use of incorrect fishing gear.

Keywords

• lake sevan
• narrow-clawed crayfish
• crayfishing
• commercial stocks