• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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• pp.263-270
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• 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
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• v.35 no.3
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• pp.243-249
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• 1999

Specificity of catches has been analyzed to japanese tuna purse seine A principle component analysis was used to improve the efficiency of fishing and increase sustainable production and productivity of Korean tuna purse seine.The result are as follows;From the principal component analysis of the fish catches, the first principal component(Z1) to promote principal component score was skipjack Kastsuwonus Pelamis, LINNAEUS and yellowfin tuna Thunnus Albacares, BONNATERRE (Small : smaller than 10kg) and proportion was 86.8% of total. The second principal component(Z2) to increase principal component score was yellowfin tuna (Large : larger than 10kg) and proportion was 9.5%.On the other hand, fish operating that have caught skipjack and yellowfin tuna (Small and Larger) was not so much. Fish catches for one species raised volume of the catches while catches for multi-species decreased it since principal composition score for one species and both species together has been increased.Fish school could be divided into three groups of schools each of which was associated with drift objects, payaho and ship, school associated with shark, whale and porpoise and school of breezing, feeding and jumping from proportion of principal component analysis for fish catches of school types. However, the biological pattern is different among school associated with ship, payaho and school associated with drift objects for analysis eigen vector. School associated with ship, payaho and school associated with drifting object associated is judged as school which be assembled to vessel and drifted log temporary.

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

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.719-729
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• 1997

Stomach contents of bigeye tuna, Thunnus obesus, and yellowfin tuna, Thunnus albacares, caught by longlining in the western tropical Pacific were analyzed to examine their foods and to compare their feeding behavior. The food species of both bigeye and yellowfin tunas were primarily fishes, crustaceans, and cephalopods. A total of 15 fish, 6 crustacean, and 1 cephalopod species were identified from their stomach contents, of which lantern fish (Myctophum sp.) was the most important food for both tuna species. No significant differences in species composition of food items between bigeye and yellowfin tunas were observed, indicating that in the same habitat the tunas have a similar feeding behavior. However, while they showed a remarkable similarity in diet composition, significant quantitative differences on the basis of IRI values were observed in several diet species, such as Myctophidae, Alepisauridae, Oplophoridae, Gammaridae, and Onychoteuthidae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.584-590
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• 2011

This study aimed to demonstrate the bioadhesive characteristics of gelatin biofilm to rat skin. The biofilm was manufactured from gelatin extracted from the acetic acid treated-skin of the yellowfin tuna Thunnus albacares. The bioadhesive strength of tuna gelatin biofilm was compared to that of porcine gelatin biofilm. The tuna gelatin biofilm exhibited a higher bioadhesive strength than the porcine gelatin biofilm. Gelatin biofilm was subjected to glutaraldehyde treatment at different concentrations, temperatures and pH in order to improve its bioadhesive strength. Glutaraldehyde treatment improved the bioadhesive strength of gelatin biofilm up to three-fold. The bioadhesive strength of glutaraldehyde treated-biofilm was significantly decreased by application of sodium borohydride.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.37-47
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• 1977

Korea started the Atlantic tuna fishery from 1964 by means of longline, then added bait-boats in 1972. Both fisheries have given the top priority to catch yellowfin tuna(Thunnus albacares). The paper reviews available catch, effort and biological data, estimates some population parameters in order to understand the status of the Atlantic yellowfin tuna as a whole. The main findings are summarized as follows: 1. The total of 476 million hook-equivalent fishing effort was thrown to catch yellowfin tuna in 1974, among which one thired was shared by longliners. 2. The dominant age group becomes younger in both surface and longline fisheries. 3. The recent mortality coefficients were calculated as 1.5 for total mortality and 0.7 for fishing mortality. 4. The weight at recruitment was 2.7 kg in 1973 which was smaller than the regulation size(3.2kg) proposed by ICCAT. 5. The maximum sustained yield was calculated to 95-145 thousand metric tons, which was the level of recent catch. Therefore, it is apparent that the present yellowfin tuna fishery should continue to receive close attention.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.38-42
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• 2000

Thig study was conducted to get a knowledge on chemical components of the cooked tuna bones (skipjack tuna bone and yellowfin tuna bone) as a food resource. The crude protein of tuna bone was around $29{\%}$ on the dry basis. The imino acid content (193 imino acid residues /1,000 amino acid residues) of collagen extracted from yellowfin tuna bone was higher than that (173 imino acid residues /1,000 amino acid residues) of collagen extracted from skipjack tuna bone, however, it was lower than that of collagen extracted from animal bone. The content and the ratio of unsatuated fatty acids in lipid extracted from yellowfin tuna bone were higher than those of lipid extracted from skipjack tuna bone, but they were lower than those of squid viscera oil. The contents of calcium and phosphorus as the major components of the tuna tone were 36.5 g and 17.2 g in 100 g ash in the skipjack, respectively, and 38.0 g and 18.7 g in 100 g ash in the yellowfin, respectively. It was concluded from these results that tuna bones could be effectively utilized as a mineral source.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.448-457
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• 1993

Deterioration of fish muscle is known to occur more quickly in the dark fleshed fish than in the white fleshed fish, causing by their high intestinal proteolytic activity. Muscle degradation which suffer post-mortem autoproteolysis is affected by trypsin with its unique activation function towards other enzymes. To compare physicochemical and enzymatic properties for the trypsins of the dark fleshed fish, trypsins from the viscera of anchovy (Engraulis japonica), and the pyloric caeca of mackerel (Scomber japonicus), yellowfin tuna (Thunnus albacores) and albacore (Thunnus alalunga) were purified through ammonium sulfate fractionation, benzamidine-Sepharose 6B, DEAE-Sephadex A-50, and Sephadex G-75 chromatography Two trypsins from mackerel (designated mackerel trypsin A and mackerel trypsin B), and one each from anchovy, yellowfin tuna and albacore were isolated as electrophoretical homogeneity, The purities of anchovy trypsin, mackerel trypsin A and B, yellowfin tuna trypsin, and albacore trypsin increased to 78.1, 4.8, 9.3, 120, and 160-fold, respectively, compared to crude enzyme solutions. Molecular weights of the trypsins from the dark fleshed fish estimated by SDS-polyacrylamide electrophoresis were ranged from 22kDa to 26kDa. The trypsins contained higher amount of glycine, serine and aspartic acid, and less amount of tryptophan, methionine, lysine and tyrosine. Optimal conditions for amidotici reactions of the enzymes were pH 8.0 and 45$^{\circ}C$ for anchovy trypsin, pH 8.0 and 5$0^{\circ}C$ for mackerel trypsin A and B, pH 9.0 and 55$^{\circ}C$ for yellowfin tuna trypsin, and pH 9.0 and 5$0^{\circ}C$ for albacore trypsin. It was supposed that the habitat temperature of the dark fleshed fish is slightly connected with the optimal reaction temperature of the trypsins of the fish.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.73.2-73.2
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• 2007

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• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.556-566
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• 2014

Korean distant water tuna longline fishery commenced in 1966 in the Atlantic Ocean. Since then, it has become one of the most important fisheries of Korea. By early of 1970s, total amount of tuna caught in the Atlantic Ocean was the highest among other Korean distant water tuna fisheries, but has become minor since 1990s. The annual catch of tuna and tuna-like species by Korean tuna longline fishery in the Atlantic Ocean was about 1,900 mt in 2013. Bigeye tuna was the predominant species in species composition followed by yellowfin tuna, Albacore tuna, Blue shark and Swordfish. Korean distant water tuna longline fishery have mainly operated in the tropical area of the Atlantic Ocean ($20^{\circ}N{\sim}20^{\circ}S$, $20^{\circ}E{\sim}60^{\circ}W$), fishing ground was almost similar as in the previous years. The length frequency of major species (Bigeye tuna, Yellowfin tuna, Albacore tuna, Blue shark and Swordfish) were estimated. As the result of length (size) frequency data on main species caught by lonline fishery in the Atlantic Ocean, main length intervals of bigeye tuna caught in 2011, 2012 and 2013 were 120~125 cm, 160~165 cm and 130~135 cm, respectively. For yellowfin tuna, those were 125~130 cm, 150~155 cm, 145~150 cm and for albacore, 109 cm, 102 cm, 109 cm and 106 cm respectively. For swordfish caught in 2011, 2012 and 2013, main length intervals were 130~135 cm, 125~135 cm and 125~130 cm, respectively, and for blue shark, 195~200 cm in 2011 and 185~190 cm in 2012, 2013.