Effects of sea surface temperature distribution patterns on the biological characteristics of neon flying squid (Ommastrephes bartramii) in the northwest Pacific Ocean

The neon flying squid (Ommastrephes bartrami) is an economically important cephalopod with a short life cycle, and its biological characteristics are highly susceptible to changes in sea surface temperature (SST). This study aims to investigate the influence of SST distribution patterns in the Northwest Pacific on the growth and development of neon flying squid, using deep learning methods to analyze termporal and spatial variations. Data on mantle length, body weight and gonad maturity of O. bartrami from July to October 2016 were analyzed, and the relationship between mantle length and body weight was modeled using a power index equation. The Deep Convolutional Embedded Clustering (DCEC) model was employed to extract SST distribution patterns from MODIS-Aqua and MODIS-Terra three-level inversion image data. The results showed that: (1) During July to October 2016, the growth and development of female and male O. bartrami in the Northwest Pacific Ocean were not completely synchronized; females exhibited a faster growth rate, while males had a faster gonad development rate. (2) Four types of SST image features extracted using DCEC model reflected the monthly SST characteristics of survey sites, corresponding to the effects of El Niño, Kuroshio Current, and Oyashio Current. (3) From July to August, squid exhibited low average body weight, mantle length, and gonad maturity, with minimal differences between sexes and no significant relationship with SST distribution pattern. (4) From September to October, when SST changed uniformly but overall temperatures were low, squid had low average weight, mental length, and gonad maturity. However, when SST changed uniformly with an overall temperature, average body weight, mantle length, and the number of sexually mature individuals significantly increased. Females grew faster than males, but male maturity rates exceeded those of females. When cold and warm waters met, forming a clear boundary, squid mantle length and weight reached their maximum, but gonad development was delayed. This study, based on the deep learning DCEC model, provides insights into the effects of SST distribution patterns on the growth and development of neon flying squid and offers a reference for further understanding the biological characteristics of O. bartrami in the Northwest Pacific.