Standardized CPUE of yellowfin tuna (Thunnus albacares) by General Linear Model (GLM) for Iranian Gillnet Fisheries in the Oman Sea

Yellowfin Tuna (Thunnus albacares) is one of the most important commercial and neritic fish species which has known because of ecological importance and wide distribution around the world. The aim of this study was to determine relative index of abundance for Yellowfin Tuna from 2007 to 2016, also we evaluated effect of some explanatory variables (year, month, vessel tonnage and net height) of catch per unit effort data in traditional gillnet fishery standardized by general linear model (GLM) in the Oman Sea. Standardized catch per unit effort is an important entrance in stock assessment as an annual abundance index. The results of this study have shown that all explanatory variables influence CPUE significantly in GLM model with lognormal error distribution; CPUE of Yellowfin Tuna increased 0.007 and0.0016 by raising one ton of vesselchr('39') tonnage and one meter of net height, respectively. Relative index of abundance of Yellowfin Tuna has the lowest quantity in 2011, remain stable till 2013 then increase to highest level in 2016, which is shown the catch rate can increase by raising catch effort. There is a seasonal trend in standard CPUE of Yellowfin Tuna with the highest catch rate in cold season. Monthly relative index of abundance has shown highest catch rate occurred in February and March.