Diversity and Distribution of 18 Cephalopod Species, and Their Link with Some Environmental Factors in the NW Pacific

Abstract

Some cephalopods are important fishery resources, with some major economic species living in pelagic waters, possessing short life history cycles, and responding strongly to environmental changes. The analysis of cephalopod community species composition, catch distribution, and their relationship with environmental factors in important marine areas can provide a basic reference for cephalopod biogeography and resource development and utilization. In this study, based on the cephalopod survey data in the spring of 2015 and summer of 2016 in the Pacific Ocean, we analyzed the cephalopod species composition, diversity index (the Margalef richness index, Shannon–Wiener diversity index, and Pielou uniformity index), main contributing species, and catch distribution in the two seasons of spring and summer in the Pacific Ocean. We also analyzed the relationship between cephalopod catch, each diversity index, and environmental factors in each season using the GAM model. The results show that 18 species of cephalopods were captured in the spring and summer, the Margalef richness index, Shannon–Wiener diversity index, and Pielou uniformity index in summer was higher than that in spring; the average catch biomass in spring was significantly higher than that in summer. The main contributing species in spring was Todarodes pacificus, while the main contributing species in summer was Ommastrephes bartramii. The interaction of the “longitude” and “latitude” has a great impact on cephalopod catch biomass in spring, and “sea surface temperature” has a great impact on cephalopod catch biomass in summer. The results of the study can provide a basic reference for the study of cephalopod diversity and resource development and utilization in the Pacific Ocean.