The investigation of the crayfish (Astacus leptodactylus eschscholtz, 1823) population amplitude in Keban Dam Lake

In this study, the crayfish (Astacus leptodactylus Eschscholtz, 1823) population amplitude in Keban dam lake was investigated. For prediction of population amplitude marking and many caunting method (Schnabel Method) was used. The study was carried out in the stations determined in Agin, Keban and Cemisgezek regions of Keban dam lake. The crayfish were marked using an electrical soldering iron. The female/male ratio of population were determined as 0.81/1.00. The regretion equation of length and weight relationships were found as LogW= -1.4534 + 2.9468LogL, and correlation was found as 0.8324. In 8.06% of crayfish, claw foot was not determined. The catching amount of unit efford was calculated as 0.93 individual crayfish/pinter/7 days. The crayfish densities were predicted as 1.82 individual/m2 in Agin region and 2.08 individual/m2 in Keban and Cemisgezek regions. Total stockes were determined as 2198560 individuals in Agin region, 2672800 individuals in Keban region and 4799142 individuals in Cemisgezek region, due to weight 58482 kg in Agin region, 71096 kg in Keban region and 127657 in Cemisgezek region. The densities of catchable length of crayfish ( 9 cm) were determined as 1.17 individual/m2 in Agin region, 1.37 individual/m2 in Keban region and 1.40 individual/m2 in Cemisgezek region. The number of catchable length of crayfish were predicted as 1413360 individuals in Agin region, 1760450 individuals in Keban region, 3230192 individuals in Cemisgezek region, due to weight 44380 kg in Agin region, 55278 kg in Keban region, 101428 kg in Cemisgezek region. It was concluded that it was necessary to continue research to make crayfish catching continuously in addition the necessary precaution must be taken according to the investigation results. Key Words: : Keban Dam Lake, Crayfish, Astacus leptodactylus, Marking, Schnabel Method