Fluctuations in distribution and relative abundance of Japanese Spanish mackerel, Scomberomorus niphonius, in the Yellow Sea, East China Sea and Sea of Japan

Abstract

To evaluate the habitat and abundance of Japanese Spanish mackerel, we analyzed catch per unit effort (CPUE) of large and mid-sized Japanese purse-seine vessels in the Yellow Sea, East China Sea and Sea of Japan using a generalized additive model and generalized linear model. An area of high CPUE was observed in the Yellow and East China seas from 1994 to 1997, but disappeared after 1998. The high-CPUE area firstly developed in the Yellow Sea from October to December, and moved to the southern Yellow Sea, East China Sea and coastal Japan from January to March. Based on the generalized additive model, Japanese Spanish mackerel appeared to prefer regions of low temperature at 10 m depth. The lowest CPUE was observed in 1996, and increased by 2000. Annual CPUE values declined from 2000 to 2003, increased subsequently (with some fluctuations) and remained largely stable after 2010. Our results comprise the first stock assessment report of Japanese Spanish mackerel based on the Japanese large and mid-sized purse seine fishery in the Yellow Sea, East China Sea and Sea of Japan. Further cooperative assessment with China and Korea is needed for accurate stock assessment and management of this species.