Effect of Dıfferent Incubators and Temperature on Artıfıcıal Incubatıon of Crayfısh <em>Pontastacus Leptodactylus</em> (Eschscholtz, 1823) Eggs

Abstract

This study aimed to investigate the effectiveness of different temperatures and incubators on the incubation of <em>Pontastacus leptodactylus</em> eggs. Eggs were collected from a total of 150 broodstock with an average weight of 52.59 ± 12.26 g and length of 13.23 ± 1.48 cm. A total of 470 eggs were placed in each incubator. Four different incubator types were used in the experiment, and each group was studied with four replications; 1. Biolife Turbojet Star X6 (biolife), 2. Jar with a flat-screen bottom, 3. Platform with a screen bottom and 4. Aquarium containing a flat-screen chamber. Only incubator number 1 had a water current that moved the egg in a certain vibration, whereas the others (2, 3, and 4) did not move the eggs. All incubators were tested at two different temperatures 15.5 oC and 19.5 oC. In both temperature regimens, a water flow of 19 ml/sec was provided to the tanks containing all incubators. Two-way ANOVA analysis revealed that the influence of temperature was not significant (p > 0.05) in terms of hatching rate, but the incubator and interaction terms were significant (p < 0.05). Significant effects of temperature and incubators without an interaction (p < 0.001) were the case for the stage II survival rate. The best hatching rate was in the Biolife incubators at both temperatures. The highest hatching rate was observed at 15.5 °C (86.74%), followed by 74.68% at 19.5 °C, while the lowest hatching rate was recorded in the aquarium, with no hatching at 15.5 °C. These groups were followed by a platform with 49.57% at 15.5 oC, an aquarium with 42.55% at 19.5 oC, jar with 41.77% at 19.5 oC, a platform with 28.01% at 19.5 oC, and jar with 14.04% at 15.5 oC. The survival rate at the stage II larval was highest in Biolife with 54.82% at 19.5 oC, while the worst was in jars and aquariums at 15.5 oC. Biolife system that moved the crayfish egg during the incubation gave better results at both temperatures. Our recommendation is that egg-moving systems should be preferred for the incubation of crayfish eggs.