Determination of exploitation model for Rutilus caspicus in south east of Caspian Sea (Golestan Province)

Rutilus caspius is one of the most important and commericial species in southeast of Caspian Sea that its catch had high fluctant in past decads for overfishing. In this study, data obtained from 246 specimens caught from coastal sein cooperative companies (they are located in the southeast coast of the Caspian Sea) during the fishing season 2014-2015 were analyzed. Results showed individuals ranging from 14.5 to 31.2 cm total length. Growth model were isometric and negative alometric in male and female, respectively. The growth parameters of L∞, K, Z, M, F and E and were computed 41.8 cm, 0.12 year-1, 1.239, 0.324, 0.916 year-1 and 0.74, respectively. Fish biomass, Maximum sustainable yield (MSY) were equal to 417 Kg and 215 Kg, while the raion of catch was 28 Kg. It seems, the rest of it was in forbidden catch. Totally, catch situation of Caspian roach is not suitable.