Long-term Changes in Biological Characteristics of Common Squid Todarodes pacificus in Response to Environmental and Stock Variability in the Korean Jigging Fishery
조민진·김무진*·김현우·강희중·김창신1
국립수산과학원 수산자원연구부 연근해자원과, 1국립수산과학원 기후환경연구부 기후변화연구과
This study classified the resource status of common squid Todarodes pacificus caught by the Korean jigging fishery between 1994 and 2023 into three periods based on the standardized catch per unit effort (CPUE): high-resource (1994-2002), resource-declining (2003-2016), and low-resource (2017-2023) periods. Biological characteristics for each period were compared and analyzed in relation to the environmental changes. Biological analyses included mantle length-body weight relationship, mantle length frequency distribution, gonadosomatic index (GSI), length at maturity, and condition factor (K). Environmental variables included sea surface temperature (SST) and zooplankton biomass. The environmental analysis revealed a delay in the timing of southward migration to suitable thermal ranges and an increase in zooplankton biomass. The biological analyses indicated that average mantle length and length at maturity (L50 and L95) continuously decreased, whereas body condition showed an increasing trend. These changes in biological characteristics suggest that resource variability and environmental fluctuations influence resource status.
Common squid, Biological characteristics, Environmental factors, CPUE, Jigging fishery