Review of changes for the Korean tuna purse seine fleet and fishing methods

The number of Korean tuna purse seiners increased rapidly every year from 1985 and reached peak at 39 vessels in 1990, followed by a steady decrease to 27 vessels in 1997. The Korean purse seine fishery has not shown significant changes in fishing methods and fishing gear. However, it is notable that in recent years, the proportion of log-school catch has shown a decreasing trend but that of free-school catch increased and the proportion of purse seiners carrying a helicopter has shown an increasing trend. Introduction The Korean tuna purse seine fishery began its commercial operation in the western Pacific in the early 1980s, about 20 years after the introduction of Korean tuna longline fishery into this region. Purse seine fishery targeting mainly skipjack and yellowfin tuna for export and domestic canning industry has developed rapidly from year to year and annual catches by this fishery increased to over 200,000 mt and reached a peak in 1991 at 227,000 mt Since then catches fluctuated widely between 200,000 mt and 130,000 mt, which mainly depend on the number of vessels operated. This paper was to review an overall trend in Korean tuna purse seine fleet, fishing methods and gear based on the data collected from fishing vessels. Data collection Fishery data on catch and fishing effort statistics for Korean tuna purse seiners have been collected by the National Fisheries Research and Development Institute (NFRDI) during the period 1980-1996. Historical data on log-school statistics have been accumulated since the early 1980s. Usually, Purse seine sets are made on a variety of schools either associated with floating objects or not Until 1991, however, the logbook data were not classified for each school type. Thus we considered it as log-school fishery when setting was done before 6 a.m. (sunrise) since setting is usually started before sunrise for log-school of tunas (Park, 1984). To collect information on the artificial floating objects such as fish aggregating device (FAD) or payao-like logs, vessel captains were interviewed when they made a visit to NFRDI and the results of interviews were presented here. Information on the changes in fishing gear or fishing method were also obtained by using the same method.