Investigation on shelter competition between narrow-clawed crayfish Astacus leptodactylus (Esch.) and noble crayfish Astacus astacus L.

A. ZAIKOV, I. PISKOV and I. ILIEV. 2010. Investigation on shelter competition between Narrow-Clawed crayfish Astacus leptodactylus (Esch.) and Noble crayfish Astacus astacus L. Bulg. J. Agric. Sci., 16: 369-375 The aim of this study was to investigate the competitive relations in the occupation of shelters between Astacus leptodactylus (Esch.) and Astacus astacus L. in laboratory conditions. A total of 240 crayfish were used in the experiment, including 120 individuals of each species and 60 individuals of each gender. Three differ- ent groups of experiments were conducted in order to fully investigate the shelter competition. The study shows that the species belonging of the individuals has a predominant significance in shelter occupation. In all variants investigated, the noble crayfish have a dominant position compared to the narrow-clawed crayfish, and gender and body weight of the specimen investigated has no effect in this regard.