Turkish Journal of Fisheries and Aquatic Sciences
2004, Vol 4, Num, 2 (Pages: 75-79)
Effects of Different Water Temperatures on the Hatching Time and Survival Rates of the Freshwater Crayfish Astacus leptodactylus (Esch., 1823) Eggs
Hamdi Aydın 1 ,M. Kamil Dilek 1
1 Kocaeli University, Gazenfer Bilge College, Department of Fisheries, 41670 Karamürsel, İzmit, Turkey
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In this study, freshwater crayfish (Astacus leptodactylus, Esch, 1823) eggs were incubated starting seven weeks after
spawning, at three different temperatures (11.8 ºC, 16±1ºC and 20±1ºC) and the results were compared with respect to
hatching time and survival rate. The eggs hatched between days 116 and 125, 88 and 97, and 69 and 74, at 11.8 ºC, 16 ±1 ºC,
and 20 ±1 ºC, respectively. The survival rates at these temperatures were 22.4%, 46.9% and 32.5%. In conclusion, it was
found that A. leptodactylus eggs could hatch 1.5 months earlier than under natural conditions by increasing water
temperature, starting in March, up to 20 ºC, but the optimum temperature for maximum hatching rate was found to be around
16ºC.
Keywords :
Freshwater crayfish, Astacus leptodactylus, hatching time, survival rate, water temperature