• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.3
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• pp.250-260
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• 2013

The annual and monthly fluctuation in the species composition and the catch abundance of dominant species were analyzed using the daily sales slip catch data by a set net in the offshore waters off Dolsan Island in Yeosu from March 2004 to December 2011. Mean catch from 2004 to 2011 is 372M/T and the maximum and the minimum catch are 526 M/T in 2005 and 27 2M/T in 2009, respectively. The dominant species were Engraulis japonicus mainly in spring and Scomberomorous niphonius in Autumn and therefore the set net catch that is dominated by S. niphonius's catch was much higher in autumn than in spring. Through comparative analyses for the environmental factors to the annual catch fluctuation, it is revealed that the water temperature variation affected the recruitment property of S. niphonius to the fishing ground but the effect of typhoon on the catch fluctuation was not distinct. Furthermore, the big blooming event of jellyfish, particularly Nemopilema nomurai, that occurred in 2009 showed a tendency of faster appearance and later extinction until December. The occurring characteristic of N. nomurai became a direct cause that brought about the lowest total catch in 2009 since the dominant species catch of the set net fishery was concentrated mostly in Autumn.

• Korean Journal of Ichthyology
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• v.18 no.3
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• pp.223-233
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• 2006

The annual and spatial changes in the species composition of catch off Yeosu were analyzed using the daily sales slip catch data by a set net in the inshore waters off Dolsan Islands in Yeosu from April to October 2001, off Yeon Islands of Yeosu from April to October 2002 and in the offshore waters off Dolsan Islands of Yeosu from April to December 2003, respectively. Scomberomorus niphonius, Seriola spp., Trichiurus lepturus, Engraulis japonicus, Sarda orientalis, Todarodes pacificus, Pampus echinogaster, Sardinella zunasi, Scomber japonicus, Lophius litulon and Loligo beka were dominant species in abundance, indicating that pelagic fish were mainly caught by a set net off Yeosu. S. zunasi, P. echinogaster, Platycephalus indicus and L. beka inhabited mainly in the inshore waters, and S. niphonius, Seriola spp., T. lepturus, P. echinogaster, T. pacificus, Takifugu porphyreus and Pagrus major resided mainly in the offshore waters as the pelagic resident species. E. japonicus was a representative dominant species moving between the inshore and the offshore waters seasonally. S. zunasi and E. japonicus occurred in the inshore waters, and E. japonicus, L. litulon and Seriola spp. begain to be caught in the deep offshore waters in spring. Total catch was high during the summer season by migration of the open sea species such as T. lepturus, S. niphonius, S. japonicus, Seriola spp., S. orientalis, P. echinogaster and T. pacificus. In fall, S. niphonius, E. japonicus, Sphyraena pinguis, Siganus fuscescens and Leiognathus nuchalis were dominant in the inshore waters, and S. niphonius, P. echinogaster, Hyporhamphus sajori, S. japonicus and T. lepturus continued to occur from summer in the offshore waters but total catch decreased, indicating the typical seasonal variation pattern of the temperate region. Most of catchable fishes by a set net were the pelagic species showing a significant temporal variation. Collection and analysis of daily catch data by large set nets can be used to determine seasonal variation in species composition of pelagic fish in a study area.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.42-49
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• 2015

According to the catch condition of Scomberomorus niphonius in autumn season affected greatly, the catch price for the set net fishery. Catch production and the selling price were relatively even except 2009 showing a great big blooming jellyfish of Nemopliema nomurai in 2008~2011. The fishing cost of the set net fishery in Yeosu has increased gradually by the decrease of catch production and unexpected environmental change like as jelly fish blooming. The increase of fishing cost diminished net income and caused a negative impact in profitability. The lowest Fisheries ratio of gross profit to gross costs the set net fishery were appeared 60.2% in 2010, respectively. Bycatch was highest in 2008 and lowest in 2009. In general, the bycatch was occurred from May to July every year and when Scomber japonicus was most dominant in the catch price by bycatch had a advantage in the profit side. However, the catch increase of immature small fishes by the bycatch, which will bring about the decrease of fisheries resources. Finally, the present state in set net fisheries will act as a defect on the long-term management of fisheries resources.