The relationship between egg size and female size infreshwater crayfish, Astacus leptodactylus

Abstract

In crayfish reproduction, one of the main factors affecting fecundity is egg size (Corey, 1991). An increase in egg size causes a decrease in fecundity in fish, gammaridean amphipods and similarly in crayfish (Abrahamsson, 1971; Ware, 1975; Steele and Steele, 1991). Although the relationship between fecundity and female size of Astacus leptodactylus has been the subject of much investigation (Cherkashina, 1970; Kossakowski, 1971; Papadopol, 1975; Stypinska, 1979; Koksal, 1988; Harlioglu, 1996), the relationship between egg size and female size of A. leptodactylus is little known (Harlioglu, 1996). Only a few studies have been carried out on crayfish species to evaluate the relation between egg size and female size (Abrahamsson, 1971; Mason, 1978; Lahti and Lindqvist, 1983; Kuris, 1991; Harlioglu, 1996). In order to have an accurate fecundity estimate, which is used in the estimation of recruitment, in addition to the relation between egg number and female size, the relation between female size and egg size should also be considered. Therefore, in the present study, the relationship between egg size and female size, and between egg wet weight and female size in A. leptodactylus was investigated. Males and females of A. leptodactylus were transferred from their natural habitat, the Agin Region of Keban Dam Lake, to the Crayfish Reproduction Unit of the Aquaculture Faculty of Firat University in Cip, Elazig in late summer of 1998. Mating and spawning started in mid-January 1999, and took approximately 3 weeks. The crayfish samples (n = 55, size range = 37–58 mm