Relationship between Pacific cod (Gadus macrocephalus) catch and environmental factors in southern East/Japan Sea

Abstract

The catch of Pacific cod (gadus macrocephalus) has increased in East/Japan Sea recently, but biological characteristics as well as recruitment processes are yet explained. Relationship between Pacific cod catch and environmental characteristics in the eastern Korea was investigated using Cross-Correlation Function (CCF) analysis and cumulative sum (CuSum). In general, there was negative correlation between total catch from southern East /Japan Sea and Arctic Oscillation Index (AOI), and the highest correlation (r = -0.451, P < 0.05) was shown with a time-lag of 4 years. CCF analysis indicated that cod catch in Korea were also significantly correlated with February temperature in the spawning ground with time-lag of 5 years. Also, we found relationship between cod catch and zooplankton biomass in Korea. For example, catch had a significant correlation with June biomass with a time-lag of 5 years (r = 0.452, P < 0.05) in the coastal area off the eastern Korea. Optimum range of adult cod caught appeared in seawater temperature at 100m depth range of 1-4℃ and salinity range of 33.8-34.2 PSU. Especially, highest catch occurred in seawater temperature range of 2-4℃ and salinity range of 33.8-34.0 PSU. These results emphasize the dynamic role cold habitats in southern East/Japan Sea.