An Investigation on Some Population Parameters of Tigris Trout (Salmo tigridis Turan, Kottelat & Bektaş, 2011) for Çatak Stream, Upper Tigris Basin/ Turkey

Abstract

The present study examined length-weight relationship and some growth parameters of Tigris Trout (Salmo tigridis Turan, Kottelat & Bektaş, 2011) caught in Çatak Stream. By using electroshock and casting nets, 162 Tigris trout were caught between January 2008 and January 2009. The fork lengths and total weights were measured, and sexes of the caught fish were identified. Furthermore, their age was also identified in line with their otoliths. The age range was found out as II–VII age. The mean of fork length was found to be 19.69 ± 3.80 cm for males and 19.89 ± 4.63 cm for females. while the mean of total weight was 97.19 ± 5.98 g for males and 102.18 ± 6.10 g for females. The length weight relationship was found as W = 0.187 · "L^2.834. Length and weight relationship according to von Bertalanffy growth equations, they were estimated as L_t =36.467 ∙ (1 -e^(-0.188 (t+1.180) ) ), Wt = 495.428 ∙ (1 -e^(-0.188 (t+1.180) ) )^2.813 respectively. In line with the samples examined, it was revealed that the population was mainly composed of II and III elderly individuals. The male/female ratio was found out as 1:2 among the samples.