1National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hatsukaichi, Hiroshima 739-0452, 2Japan Sea National Fisheries Research Institute, Fisheries Research Agency, Niigata 951-8121, 3Seikai National Fisheries Research Institute, Fisheries Research Agency, Nagasaki 851-2213, Japan
We studied seasonal changes in groundfish species composition in the East China and Yellow Seas. Specimens from five surveys in these areas from 1986 to 1991 were classified into species, weighed and counted. Water temperature and salinity were measured at each survey site with a conductivity-temperature-depth (CTD) profiler. Number of species, species diversity, and abundance per season were calculated for the combined survey area. Groundfishes in the East China and Yellow Seas comprised 334 species from 121 families. The dominant species were Japanese anchovy (Engraulis japonicus), Black scraper (Thamnaconus modestus) and Japanese jack mackerel (Trachurus japonicus). Water temperatures of the bottom layer were higher in autumn than in spring-summer or winter. Salinities of the bottom layer were higher in spring-summer and winter than in autumn. Species richness, species diversity and median values for both number of species and abundance were highest in autumn (October-December). The numbers of species per survey site were greater in the southern East China Sea than in other areas in all seasons.