Some biological properties of freshwater crayfish (Astacus leptodactylus Eschscholtz, 1823) in lake Manyas

ABSTRACTThis study, was carried out between 10.10.2002 and 25.11.2003. Freshwatercrayfishes (Astacus leptodactylus) were obtained from a selected area. Meat yield,fecundity, length-weight relationships, life cycles, length frequency and reproduction ofthis species were investigated in Lake Manyas.In the present study, which was carried out under the project of Lake Manyas-YDABAG TUBITAK (Project No: 118Y101), crayfish samples were caught by trapswith a 22 mm net mesh size and collected by a 7,5 m fisherman boat. The samples wereprocessed at the research laboratory of COMU Fisheries Faculty. Biometricmeasurements such as total length, carapace length, carapace width, tail length, tailwidth, chelae length, chelae width, propodus length and wet weigth of the samples weremeasured arter freezing at -18 ºC. Measured crayfishes were cooked for 10 minutes inorder to determine meat yield. For the fecundity of mature female crayfish ovariumswere weighed and counted in the reproduction season. Physico-chemical (pH,temperature) parameters of the sampling area were analyzed in situ.Key Words: Astacus leptodactylus, Freshwater crayfish, biometric relationships, meatyield, fecundity, Lake Manyas.7