The off-shore paired trawlers and danish seiners catch benthic fish at around Tsushima strait and adjacent waters. Majority of target stocks are yellow sea bream Dentex tumifrons, red sea bass Doederleinia berycoides and three species of flat fishes, spotted flounder Eopsetta grigorjewi, willowy flounder Tanakius kitaharai and long nose flounder Hippoglossoides pinetorum. They are warm water species exceptlong nose flounder. The long term fluctuation of stock - recruitment relationships of the stocks were analysed using virtual population analysis by back calculation with Pope's approximation equation. The RR, which is relative distance from Ricker type stock-recruitment model, was evaluated as the index of year-class strength. The RR of four warm water species showed positive correlation with sea water temperature，but that of long nose flounder was negative.
Benthic fish population
sea water temperature
Ricker type stock-recruitment model
virtual population analysis (VPA)