An investigation on the population parameters of freshwater crayfish (Pontastacus leptodactylus Eschscholtz, 1823) in Lake Yeniçağa (Bolu)

Abstract

This study examines the monthly population parameters of Pontastacus leptodactylus in Lake Yeniçağa, including sex, length, and weight compositions, length-weight relationship, fecundity, morphometry, meat yield, and crayfish plague ratio. For this purpose, 641 crayfish were collected using fyke nets with a 34 mm mesh size. The females carrying eggs were observed between February and May. The female specimens carried between 103 and 841 eggs each, with a diameter ranging from 2.03 to 2.82 mm. The research revealed a size range of 80–168 mm and weight range of 15–133 g for crayfish specimens. As a result of regression analyses, the length-weight relationship was calculated as W = 0.0392L^2.9148 for males and W = 0.0701L^2.6139 for females. The population exhibited negative allometric growth based on the length and weight data. The evaluation of meat yield was based on the total meat yield, which comprises cheliped meat yield and abdomen meat yield. The study found that 14.35% of the P. leptodactylus population in Yeniçağa Lake was affected by crayfish disease. The results indicate that the P. leptodactylus population in Lake Yeniçağa has an overall healthy population structure, with a size suitable for fishing, and should be considered from an economic standpoint.