CPUE standardization of Illex argentinus for Chinese Mainland squid-jigging fishery in the southwest Atlantic Ocean

Abstract

Illex argentinus is one of the most important squid-jigging fishery of Chinese Mainland in Southw est Atlantic Ocean.It is necessary to standardize the catch per unit effort(CPUE) in the stock assessment.Generalized linear models(GLM) and generalized additive models(GAM) w ere used to standardize catch per unit effort(CPUE) of Illex argentinus for Chinese squid-jigging fishery in the southw est Atlantic Ocean based on the production data from 2000 to 2010 collected by Chinese Squid-jigging Technology Working Group and the environmental variables including sea surface temperature(SST),sea surface height(SSH) and chlorophyll-a(Chl-a).The GLM analysis indicated that the importance of four variables ranked by decreasing magnitude: Year,Latitude,Year × Latitude and SST.How ever,the GAM show ed that the model including Year,Month,Longitude,Latitude,SST,SSH,Year × Latitude and Year × Longitude w as the optimal model based on AIC and could explain 49.20% of the variance in nominal CPUE.GAM analysis indicated that high CPUEs w ere found in the area betw een 46.5° and 48.5°S at SST ranging from 12 ℃ to 16 ℃ and SSH ranging form-20 to 20 cm in summer.In this study,GAM tended to be more suitable than GLM in analysis of CPUE.