Fecundity of Stone Crayfish Austropotamobius torrentium from Two Different Populations in Bulgaria

Institute of Fisheries and Aquaculture, BG-4003 Plovdiv, Bulgaria


HUBENOVA, T., P. VASILEVA and A. ZAIKOV, 2010. Fecundity of stone crayfish Austropotamobius torrentium from two different populations in Bulgaria. Bulg.J.Agric.Sci., 16: 387-393

The aim of the study was to establish the sexual maturity, pleopodal egg number and egg size in the stone crayfish from two different biotopes - a dam-lake and a river, at the end of the reproductive period - shortly before larvae hatching. The obtained results are the first data on this species in this country. In both investigated biotopes stone crayfish females seemed to reach sexual maturity at a very closed total length of 62-64 mm and at carapace length of 29 mm. The average egg number of 78 for the females in the Mrachenik River were estimated, while the egg number of the females from Dospat dam-lake are lower - only 29. In Mrachenik River the minimum registered egg number was 21 and the maximum 125. In Dospat dam-lake the minimum registered egg number was 11 and the maximum 66. An average size of 3.2 mm egg diameter and 0.019 mg egg weight for the females from Dospat dam-lake, and an average size of 2.8 mm egg diameter and 0.013 mg egg weight for the females from the Mrachenik River were established. Egg size diameter and weight did not show any significant correlation, neither positive to maternal female size, nor negative to total amount of eggs. The differences in pleopodal egg number and egg size in the both investigated populations are probably in connection with the influence of some environmental factors as temperature, duration of the reproductive period, food and shelters availability and etc.

Key words: stone crayfish (Austropotamobius torrentium), sexual maturity, pleopodal egg number, egg size

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