여수해역 정치망어업의 환경요인변화에 의한 경영수지분석

Abstract

The annual and monthly variation in the species composition and the catch abundance of dominant species were analyzed using the daily sales slip catch data by a set net off Dolsan Island in Yeosu from March 2004 to December 2011. Mean catch amount during study period is 372 M/T and the maximum and the minimum catch are 526 M/T in 2005 and 272 M/T in 2009, respectively. The dominant species were Engraulis japonicus in spring and Scomberomorous niphonius in Autumn and the total catch of set net was dominated by S. niphonius's catch. Through comparative analyses for the environmental factors to the annual catch variation, it is revealed that the fluctuation of water temperature affected the recruitment characteristic of S. niphonius to the fishing ground but the effect of typhoon on the catch fluctuation was not distinct. Furthermore, the recent bloom of jellyfish, particularly Nemopilema nomurai, has showed a tendency of faster appearance and later extinction from June to early December. The big bloom of N. nomurai in 2009 act a direct cause on the lowest total catch during the study period. According to the catch condition of S. niphonius in autumn season, the catch selling price flucuated greatly. Catch production and the selling price were relatively even except 2009 shown a great big blooming jellyfish of N. nomurai. The fishing cost rate of the set net fishery in Yeosu has increased gradually by the decrease of catch production and unexpected environmental change. The increase of fishing cost diminished net income and caused a negative impact in profitability. The highest net income and profit rate the setnet fishery were appeared 345 million won and 0.4 in 2010, respectively. Scomber japonicus was most dominant in bycatch and its catch less than 20cm was highest in 2008 and lowest 2009. In general, the price of bycatch was shown from May to July every year and the catch selling price of bycatch had the advantage in the profit side. However, the bycatch will promote the indiscreet catch of immature small fishes, which will bring about the decrease of fisheries resources. Finally, the present state in set net fishing will act a defect on the long-term management of the set net fishery.