Stock assessment and management implications of horse mackerel (Trachurus japonicus) in Korean waters, based on the relationships between recruitmentand the ocean environment

This study presents an example of horse mackerel (Trachurus japonicus) stoc k to demonstrate that marine environmental factors are important in stock a ssessment for the new Korean Total Allowable Catch (TAC)-based fisheries ma nagement system. The estimated survival rate (S) of horse mackerel ranged f rom 0.25 to 0.36. The instantaneous coefficient of natural mortality (M) wa s 0.48/year, and the age at first capture was 0.83 year. Annual biomass of horse mackerel in Korean waters was estimated by a biomass-based cohort ana lysis using annual catch in weight at age during 1965-1995. Yield-per-recru it and spawning biomass-per-recruit were estimated under various harvest st rategies at F-max F-0.1, F-30%, and F-40%. A method for estimating acceptab le biological catch (ABC) is proposed for dealing with the large difference s in the quality and quantity of information and data available. Using recr uitment of horse mackerel estimated from various spawner-recruitment relati onship models combined with salinity, volume transport, and zooplankton bio mass as environmental factors, the ABC under the best information available was estimated to range from 3100 to 3800 mt. (C) 2001 Elsevier Science Ltd . All rights reserved.