Characteristics of Fecundity of Narrow-clawed Crayfish (Astacus leptodactylus Esch.) Population in Kardjali Reservoir with a View to Their Economic Exploitation

Institute of Fishery and Aquaculture, BG-9000 Varna, Bulgaria


HUBENOVA, T., P. VASILEVA and A. ZAIKOV, 2002. Characteristics of fecundity of narrow-clawed crayfish (Astacus leptodactylus Esch.) population in Kardjali reservoir with a view to their economic exploitation. Bulg. J. Agric. Sci., 8: 301–306

The objective of the study is to determine the absolute fecundity of sexually mature crayfish in Kardjali reservoir and its dependency on some major exterior parameters of the body such as length and weight of the body, length and width of the carapax. The investigation was carried out on 113 species that were caught in the beginning of the reproduction season (November-December) in Kardjali dam lake.
It was found that the increasing the weight of the body results in increasing the weight of the ovary and the number of mature oocytes in it (absolute fecundity) whereas the relative share of the ovary (GSI, %) decreases. Absolute fecundity correlates positively both with the length of the body and the length and width of the carapax. It is greatest with the weight group of 50–70 g and 12.9 cm – 369.67 nr oocytes, but crayfish of such dimensions can be found in rare cases. Species with dimensions of 20–50 g and 9.86–11.2 cm which account for 69% of the examined sample with average absolute fecundity of 205.61–295.95 nr oocytes are of importance to the reproduction potential of the population.

Key words: narrow-clawed crayfish (Astacus leptodactylus Esch.), fecundity