Assemblage Distribution of the Larval and Juvenile Myctophid Fish in the Kuroshio Extension Region: Winter 2020

Myctophids are an ecologically important mesopelagic species in the eastern Pacific Ocean. Due to the wide distribution, great diversity and variable biological characteristics of the species, there is a lack of reliable information regarding their spawning and nursery grounds in the Kuroshio extension region. In this study, we identified a total of 110 myctophid individuals using DNA barcoding and morphological techniques, among which, the dominant genus was Ceratoscopelus, comprising 37.27% of the entire catch. The abundance of each sampling station was calculated, and its relationship with environmental variables was analyzed. Tweedie-Generalized Additive Model (GAM) analysis showed that copepod density, oceanic dynamic processes, and sea surface temperature were the primary factors influencing the distribution pattern of larvae and juvenile myctophid fish. The results further indicate that the Kuroshio extension plays a dominant role in the biological processes of these fish in this region. These findings provide crucial dynamic information for the scientific conservation and exploitation of myctophids, which could have significant implications for the management of these fish populations.