Inter-annual variation in abundance index of Dosidicus gigas off Peru during 2003 to 2012

Abstract:

Dosidicus gigas is one kind of important economic fish in the world and also one of the most important squid jigging species of Chinese Mainland. According to the fishery-dependent data of 2003-2004 and 2006-2012 by squid jigging boats of Chinses Mainland and the environment data from satellite remote sense, we standardised the CPUE of Dosidicus gigas off Peru by generalized linear model(GLM) and generalized additive model(GAM).We analysed the inter-annual variation of Dosidicus gigas off Peru.By significant testing, the 9 variables chosen into the model are year, month, latitude, longitude, concentration of chlorophyll-a, interaction of year and longitude, interaction of year and latitude, interaction of month and longitude and interaction of month and latitude. The results of GAM indicate that coefficient of determination (R²) is 42.3% which is high. The standardized CPUE has the same trends with nominal CPUE and the average value is a little lower than nominal CPUE. The inter-annual variation of Dosidicus gigas abundance off Peru during 2003－2012 is severe, the highest value of abundance appeared in 2004, the average CPUE after standardizing by GLM was 7.94t/d; the lowest value of abundance appeared in 2007, the average CPUE after standardizing by GLM was3.28t/d.