• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.52 no.2
• /
• pp.149-161
• /
• 2016

Fishing characteristics of Korean tuna purse seine fishery in the Pacific Ocean were investigated using logbook data compiled from captain onboard and the statistical data from 1980 to 2014. Changes in fishing ground and correlation between marine environmental factors and fishing patterns were investigated using Oceanographic index. The proportion of unassociated set was higher than that of associated set. The catch proportion of yellowfin was higher in the unassociated set, while that of skipjack and bigeye was higher in the associated set. Due to vessels, fishing gears and Korean captains' high-level of skills in fishing technology optimized for the unassociated set and preference of large fishes, especially large yellowfin tuna, it showed unique fishing characteristics focusing on the unassociated set. As for fishing distributions of Korean tuna purse seine fishery and impacts of oceanographic conditions on the fishery, the main fishing ground was concentrated on the area of $5^{\circ}N{\sim}10^{\circ}S$, $140^{\circ}E{\sim}180^{\circ}$ through the decades. When stronger El-nino occurred, the range of fishing ground tended to expand and main fishing ground moved to the eastern part of western and central Pacific Ocean. During this season, yellowfin tuna had high CPUE and catch proportion of yellowfin tuna in the eastern part also increased. As for the proportion of fishing effort by set type, proportion of log associated set was high during El-nino season while that of FAD associated set was high during La-nina season.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.41 no.4
• /
• pp.263-270
• /
• 2005

This paper summarizes characteristics of the Korean tuna purse seine fishery in the Western and Central Pacific Ocean (WCPO). Major fishing area for the Korean tuna purse seine fleet consisted of the waters of Micronesia, Papua New Guinea and Solomon Islands and adjacent high seas between $130^{\circ}E-180^{\circ}$ The center of the Korean tuna fishing ground was in the vicinity of $180^{\circ}$ during the El - $Ni{\tilde{n}}$o event but was formed in $150^{\circ}-160^{\circ}$E during the La - $Ni{\tilde{n}}o$ event. As compared with other major purse seine fleets in WCPO, the Korean fleet set more on unassociated schools of tuna, while Japan, USA and Chinese - Taipei fleets accounted for more than 50% of sets on log - associated schools. In general, CPUES for log - associated schools were higher than those for unassociated schools and catch composition showed that yellowfin ratio was higher in unassociated shools than log - associated schools. Length frequency represented higher percentage of mid - sized yellowfin than Japanese and USA fleets. Daily set numbers and CPUE were high before 7 am and remained almost constant from 7 am to 3 pm but decreased rapidly after 3 pm and 5 pm, respectively. Catch composition per set indicated that pure skipjack school was caught most frequently, followed by mixed school and pure yellowfin school as the least, but CPUE was highest for the mixed school.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.3
• /
• pp.414-423
• /
• 2015

Fishing trend and characteristics of Korean tuna purse seine fishery in the Pacific Ocean were investigated using logbook data compiled from captain onboard and the statistical data from 1980 to 2013. The historical catch of this fishery had sharply increased since mid-1980s, and it has shown fluctuations with about 2-3 hundred thousands, whereas the catch per number of vessel has steadily increased with fluctuations since commencing this fishery. As for the proportion of catch by set type, unassociated type had increased from the mid-1980s to the end of 1990s, and then has decreased up to 2010s. Associated type had decreased continually to the end of 1990s, however, it started to increase since the beginning of 2000s. As for the catch proportion of set type by main species, those of skipjack tuna and bigeye tuna showed higher in the associated type, whereas that of yellowfin tuna has the highest proportion in the unassociated type. Fishing distribution of Korean tuna purse seine fishery was concentrated on the area of $5^{\circ}N{\sim}10^{\circ}S$ and $140^{\circ}E{\sim}180^{\circ}$ through the decades. The monthly catch distribution by longitudinal zone of Korean tuna purse seine fishery expanded the most further to the eastward in September to October.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.52 no.3
• /
• pp.197-208
• /
• 2016

The WCPFC CMMs related to tropical tunas have been strongly restricting fishing capacity and operating activities of main fisheries, especially purse seine fishery. In terms of changes in fishing trend by implementing relevant measures of FAD set, the number of FAD set by Korean purse seine fleet showed a decreasing pattern with the lowest level of FAD set proportion among major distant water fishing nations. With regards to the FAD closure, there was no significant change in fishing effort but a drop in catch, especially bigeye tuna during the period of FAD closure. Moreover, it showed closely similar trends between the number of FAD set and bigeye tuna catch. In terms of measures related to the high sea area including a ban on fishing on the HSP and limitation of fishing days on the high sea by flag state, proportions of catch and effort on the high sea had sharply declined after implementing those measures. As relevant measures are expected to be strengthened, it should pay attention to change of coastal nations policies and focus on improving fishing efficiency of unassociated school set with multi-pronged efforts.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.52 no.4
• /
• pp.356-363
• /
• 2016

To suggest more efficient fishing operation, it was analyzed using five years (2011~2015) catch data of six Korean-flagged tuna purse seiners (with 1000 mt of haul capacity) operating in the western and central Pacific Ocean. In terms of annual total catch, it presented a two-year cycle of variation on catch, showing that catches of 2012, 2014 and 2015 were high, whereas those of 2011 and 2013 were low. The proportions on fishing effort of associated set were around 21.9~30.8% having 21.5~45.0% of total catch. In this study, there was no significant difference between catches of unassociated set and associated set. When considered having good fishing conditions, fishing activities were concentrated in the areas of Papua New Guinea (PNG) and Kiribati, while it showed that fishing ground spreaded out to the areas of not only PNG and Kiribati but also Federated States of Micronesia (FSM), Tuvalu and Solomon islands. The average number of fishing days was 271 with a range of 246~285. As restriction on fishing operation such as reduction of fishing days and higher fishing fee are expected to strengthen, the result of this study will be helpful to select more efficient fishing methods for purse seine fishery based on fishing conditions.