Mechanisms analysis of the stock abundance index for the winter-spawning cohort of Todarodes pacificus based on the factor of SST

Abstract:

Understanding and mastering the environmental factors that affect the resource abundance of the winter-spawning cohort of Todarodes pacificus are of great significance to the development of fishery forecasts and fishery resource assessment and management.In this study, Sea Surface Temperature (SST) was used to measure the catch per unit effort (CPUE) of the winter-spawning cohort of Todarodes pacificus from 1998 to 2018, the spawning ground (25°N-40°N and 125°E-145°E) during the spawning period from January to March, and the feeding ground (26°N- 40°N and 125°E-145°E) during the feeding period from June to July,the SST value affecting CPUE was obtained by generalized linear model analysis, and we made the spatial overlay analysis of the CPUE and the obtained influence factor SST in consecutive high-value years (2007, 2008, 2009) and consecutive low-value years (2016, 2017, 2018).The results showed that CPUE and spawning ground SST from January to March were significantly related to January (25°N-40°N and 125°E-144.5°E),and the optimal range of SST in this sea area was 18-26 ℃. The significant correlation between CPUE and SST in June and July was mainly concentrated in July (27°N-39.5° N and 125°E-144.5°E), and the optimal range of SST in this sea area was 18-28 ℃,the SST of consecutive high value CPUE years was lower than that of consecutive low value years. The study suggests that the stock abundance of the winter-spawning cohort of Todarodes pacificus was significantly affected by SST.