Effect of coloured Gillnet on sturgeon fishing in the southwest of the Caspian Sea

Effectiveness of different coloured gillnets on Sturgeon fishing was investigated in Shahid Ghassemy fishing Station in Guilan Fishery Region. Green, blue and black gillnets were compared with undyed white gillnets usually fished for Acipenser stellatus and A. persicus, in coastal fisheries operation in the area. Netting material were nylon-Polyamide. Their physico-mechanical properties, construction, mesh size, type of twine, thickness of twine, total weight of the sinkers and the number of floats, buoyancy force, fishery condition were equal during experiments. The analysis of CPUE data described the impact of green colour gillnets demonstrated more catch per 1000 meters, per day fish No. : 2.203, fish Wt.(Kg) 30.863, Caviar wt.(Kg) 4.336. Blue colour gillnets fish No.: 2.027 fish wt.(Kg) 34.567 Caviar wt.(Kg) 4.898. Undyed white colour gillnets. In comparison with green colour gillnets vas shown least catch fish No.: 0.415, fish wt.(Kg) 4.392, Caviar wt.(Kg) 0.581. The results indic.....