The effect of Hanging Ratio Factor on the catch amount of multifilament gill nets in coastal waters of Bushehr province, Persian Gulf

The aim of this study was to comparing the effect of different hanging ratios (E=0.5 and 0.6) of drift gillnets on catch rates, length composition and Catch per Unit Effort (CPUE) in Bushehr coastal waters between late September 2010 to late March 2011. The length frequency of Spanish Makerels did not differ significantly between gillnets with 0.5 and 0.6 hanging ratios (P>0.05). A total of 55889 kg of various large pelagic species were caught during 6 cruises in six months that 26409 and 29552 kg were related to gillnets with 0.5 and 0.6 hanging ratios, respectively. The catch composition of gillnet with 0.5 hanging ratio was included: Thunnus tonggol %48.81, Euthynnus affinis %25.41, Scomberoides commersonnianus %17.02, Carcharhinus amblyrhynchoides %3.87, Scomberomorus commerson %3.39, Rachycentron canadum %1.17, Sphyraena jello%0.33 and species composition of gill net with 0.6 hanging ratio was included: Thunnus tonggol %52.18, Euthynnus affinis %24.29, Scomberoides commersonnianus %16.52, Scomberomorus commerson %3.33, Carcharhinus amblyrhynchoides %2.88, Rachycentro ncanadum %0.61 and Sphyraena jello%0.19. The CPUE did not differ significantly between two gillnets (P>0.05).