AN INVESTIGATION ON THE STURGEON STOCKS IN SOUTHERN CASPIAN SEA

We launched a summer and winter cruise using two fishing vessels to assess the stocks of the sturgeon fish in the southern coasts of the Caspian Sea in the year 2004-2005. Eighty five random stations were selected and sampled using a 9 meter trawl in waters less than 10 meters and a 24.7 meter trawl for the depths above 10 meters. We caught 170 sturgeons in the summer cruise which comprised 142 Acipenser persicus, 19Acipenser stellatus, 4 Huso huso, 3 Acipenser nudiventris and 2 Acipenser guldenstadtti. In the winter cruise, 118 sturgeons were caught of which 75 were Acipenser persicus, 41 were Acipenser stellatus, 1 was Acipenser nudiventris and 1 was Acipenser guldenstadtti.
Catch per unit effort (CPUE) was calculated as 2 fish for summer cruise with the Acipenser persicus being the most abundant species with 1.67 individuals per trawling while for Acipenser stellatus this was 0.22. For Huso huso, the CPUE was 0.05 and for Acipenser nudiventris it was 0.04. For winter cruise, the CPUE was calculated as 1.38 fish, again with the Acipenser persicus as the most abundant with 0.88, while that of the Acipenser stellatus was 0.48. The CPUE for Acipenser guldenstadtti and Acipenser nudiventris was 0.01 in the winter cruise.