The Effects of temperature, eyestalk ablation and stocking rate on egg incubation time, survival rate, growth, and meat composition of Turkish crayfish (Astacus leptodactylus)

ABSTRACT PhD THESIS THE EFFECTS OF TEMPERATURE, EYESTALK ABLATION AND STOCKING RATE ON EGG INCUBATION TIME, SURVIVAL RATE, GROWTH, AND MEAT COMPOSITION OF TURKISH CRAYFISH (Astacus leptodactylus) BAYBARS SAGLAMTIMUR DEPARTMENT OF FISHERIES INSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OF ÇUKUROVA Supervisor: Assoc.Prof.Dr. Metin KUMLU Year 2002, Page 148 Jury: Assoc.Prof.Dr. Metin KUMLU Prof.Dr. Gürkan EKİNGEN Asst.Prof.Dr. Nazmi TEKELÎO?LU Asst.Prof.Dr. Sedat KARAYÜCEL Asst.Prof.Dr. Mahmut Ali GÖKÇE This thesis is comprised of three different experiments: In experiment I, the effects of uni or bi-lateral eyestalk ablation, and HCG injections of various dosages were investigated on mating and spawning time, and eggs of Turkish Crayfish (Astacus leptodactylus Esch.) broodstock. Bi-lateral eyestalk ablation shortened spawning time by 25 days in comparison to the control group whereas; uni-lateral eyestalk ablation and HCG injections had not effects on reproduction. Bi-lateral eyestalk ablation has physiologically forced the females to moult more frequently and this resulted in the loss of eggs that had been adhered to the abdomen. In experiment II, artificial incubation of eggs at an early embryonic stage under various water temperatures (natural, 20, 24 and 28°C) was studied in order to shorten the incubation period. At the early embryonic stage, the eggs in none of the groups had completed artificial incubation successfully. In experiment III, the effects of three temperatures (20, 22 and 25°C), bi-lateral eyestalk ablation and two stocking densities (15 and 30 animals/m2) were investigated on moulting, growth, survival, abdomen and abdominal meat rates, and meat quality of this crayfish species. Bi-lateral eyestalk ablation was found to shorten moulting interval and increase growth (two fold) as compared to intact animals. Different temperatures was found to have no significant effect on growth. Keywords: Astacus leptodactylus, Temperature, Eyestalk Ablation, Hormone, Incubation II