• 수산해양기술연구
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• 제52권2호
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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.

• 수산해양기술연구
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• 제56권4호
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• pp.277-291
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• 2020

In order to understand characteristics on bycatch of Korean tuna purse seine fishery, especially operations associated with Fish Aggregating Device (FAD) in the Indian Ocean, we conducted analyses related to bycatch by school association type (unassociated school, FAD associated school and log associated school) using the data collected by scientific observers from 2016 to 2018. The FAD used by Korean tuna purse seine fishery in the Indian Ocean was a drifting FAD, which belongs to non-entangling FADs according to the category proposed by the International Seafood Sustainability Foundation (ISSF). The target species of Korean tuna purse seine fishery are skipjack, yellowfin and bigeye tunas, accounting for 99% of the total catch. The ratio of bycatch was 0.97% in total catch and the discard accounted for less than 1%, indicating that most catch was retained on board. In terms of bycatch ratio by school association type, it accounted for 0.12% for unassociated school, 1.09% for FAD associated school and 1.25% for log associated school. As for the catch proportion of shark species by school association type, it accounted for 0.01% for unassociated school, 0.11% for FAD associated school and 0.10% for log associated school, which showed that unassociated school type was the lowest to affect bycatch of non-target and shark species. Given the proportion of bycatch compositions, however, it is considered that FAD associated school of Korean tuna purse seine fishery has less caught bycatch species of non-target and shark, compared to other fleets operating in the Indian Ocean.

• 수산해양기술연구
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• 제56권4호
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• pp.299-315
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• 2020

Tuna fisheries were applied to an integrated ecosystem-based fishery risk assessment method using indexes of target species status, inhabited species in a target ecosystem, habitat quality and socio-economic benefit of affected fisheries. This study suggested more effective and efficient management measures to break away from traditional management methods, such as limitation of catch and fishing effort. The results presented that the objective risk index (ORI_S) on sustainability of bigeye and yellowfin tunas by purse seine fishery was estimated high due to the high catch ratio of small fishes. The ORIs of biodiversity (ORI_B) and habitat quality (ORI_H) of purse seine fishery were also estimated at a high level from using fish-aggregating devices (FAD). However, due to skipjack tuna's high catches, the ORI of socio-economic benefit (ORI_E) was estimated at a very low level. Due to the high bycatch rate, ORI_B was high, and ORI_S and ORI_H were evaluated at a low level in longline fishery. Due to strengthern of fishing restrictions and increase of fishing costs, the ORI_E was assessed to be very high. The ecosystem risk index (ERI) for two tuna fisheries was assessed low, but the overall FAD management by purse seine fishery is necessary at the ecosystem level.

• 한국수산과학회지
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• 제40권6호
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• pp.367-373
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• 2007

We assessed the stock of the southern bluefin tuna (SBT, Thunnus maccoyii) by applying the MULTIFAN-CL model. The model is spatially disaggregated, with the population and fisheries stratified into a number of regions within the overall stock range. Catch, effort, length-frequency, and tagging data from 1965 to 2003 were stratified by three regions and four quarters (Jan-Mar, Apr-Jun, Jul-Sept and Oct-Dec). These data were used to estimate the instantaneous fishing mortality (F), biomass, spawning biomass, recruitment, and so on. The Commission for the Conservation of Southern Bluefin Tuna (CCSBT) used only Japanese data and did not consider migration for the SBT stock assessment. By contrast, we used Japanese, Australian, New Zealand, Taiwanese, and Korean data, and considered migration. As a result, the estimated annual average F of all age classes was 0.073/yr and the F of age class 6-10 was the highest. The results also showed that the biomass and recruitment of SBT had declined significantly after 1965. Compared with the CCSBT results, the estimated spawning biomass in this study was lower and more uncertain. However, we will conduct a sensitivity analysis to get more accurate biological parameters and results. In addition, we need to use the bootstrap resampling method to quantify the uncertainty.

• 한국수산과학회지
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• 제50권6호
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• pp.684-693
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• 2017

We investigated methods for extracting histidine-containing low-molecular-weight (LMW) peptides such as anserine, carnosine and histidine from the edible meat of tuna byproducts. Extracts were treated by several methods including heat treatment ($80^{\circ}C$, 10 min), DOWEX ion exchange (IEC), ultrafiltration (UF), and carboxymethyl (CM)-cellulose column chromatography (IEC+CMC); then the levels of protein, total iron, histidine, carnosine, and anserine were measured. Extracts treated with IEC+CMC using CM-cellulose were analyzed for total iron, protein, histidine, and anserine content, which were $6.27{\pm}0.26mg/mL$, $5.20{\pm}0.21{\mu}g/mL$, 0.80 mg/mL, 0.208 mg/mL, and 4.40 mg/mL, respectively, in yellowfin tuna; and $9.05{\pm}0.82mg/mL$, $4.06{\pm}0.20{\mu}g/mL$, 1.62 mg/mL, 0.012 mg/mL, and 7.28 mg/mL in bigeye tuna. By comparison in IEC-UF treated extracts, protein, total iron, and histidine content decreased by 43%, 73%, and 27% in yellowfin and 0.4%, 54%, and 23% in bigeye tuna, wheres carnosine and anserine content increased by 22% and 17%, respectively. Freeze-dried (FD) extracts exhibited similar trends as non-dried extracts, i.e., dipeptide content increased with purification steps, whereas pro-oxidant (total iron and protein) content decreased. IEC+CMC treated FD extracts had the highest anserine, content, and the greatest reductuion in pro-oxidants.

• 수산해양기술연구
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• 제52권3호
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• pp.197-208
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• 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.

• 한국식품조리과학회지
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• 제23권2호통권98호
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• pp.221-226
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• 2007

This study was carried out to investigate the optimun conditions for the isolation of low molecular weight peptides containing histidine, and to evaluate the antioxidant effects of skipjack boiled extracts(SBE). The results are summarized as follows : L-histidine contents of the ordinary muscle and dark muscle extracts were $ 83.1{\pm}1.75{\mu}M/g\;and\;11.0{\pm}2.39\;{\mu}M/g$, respectively. The L-histidine level of the dark muscle was much lower than that of ordinary muscle in the SBE. The extracts were treated with alcalase and neutrase under different pH levels, temperatures, and times. The optimum hydrolysis conditions of SBE were pH 7.0 and a $60^{\circ}$C temperature for 2 hr in the batch reactor, which hydrolyzed 63% of the SBE. HPLC analysis showed a removing effect of the ultrafiltration permeate (UFP) to high molecular weight impurities in SBE. SBE and pure carnosine participated as inhibiting agents to, which was confirmed through the autoxidation processing of linoleic acid. UFP treatment improved the inhibiting ability of SBE to the autoxidation of linoleic acid. The reducing power of the UFP-treated ordinary muscle extracts were 10-fold higher than the dark muscle extracts, and 0.7-fold higher than 20 mM pure carnosine. The UFP-treated ordinary muscle extracts had greater reducing power activity than pure carnosine. The scavenging activities on DPPH radical of the different treated-SBE and pure carnosine were also investigated. Scavenging activities of the ordinary and dark muscle extracts and the pure carnosine were 90%, 70%, and 45%, respectively. In summary, Skipjack boiled extracts (SBE) demonstrated that low molecular weight peptides containing histidine are capable of inhibiting lipid oxidation. They also possessed effective abilities as free radical scavengers and reducing agents, and these activities may increase with increasing concentrations.

• 동의생리병리학회지
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• 제18권1호
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• pp.93-100
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• 2004

This study was carried out for analyzing pathological and epidemiological factors of osteoporosis and doing pilot test using trial compounds of tuna bone and oriental herbs based on the factors. Osteoporosis is originated from osteoblast, osteoclast, organic and inorganic factors etc. Therefore the pathology of osteoporosis is not simple because the cytokine, growth factors and hormones of the components are various a lot. Taking a view of epidemiological factors of type I osteoporosis, ageㆍmenarcheㆍcholesterolㆍBMI etc. have definite relation to them. So we can approach to aging or consumptive disease in oriental medicine, specifically differential diagnosis of blood depletion with deficiency of qi, deficiency of kidney, deficiency of yin, bony weakness etc. And it should be considered together with rules for maintaining good health or habit concomitantly. Therefore IL1ㆍ6 or TNF αㆍβ are generally used as molecular biological index for osteoblast and osteoclast because the most important index is bone mineral density and strength, but the factors like collagen and noncollagen protein must be accounted as biomarkers. Trial compounds generally showed favorable effects on accompanying subjective symptoms of osteoporosis in the pilot test for menopausal woman. But if she didn't have specific symptoms of osteoporosis there wasn't any specific change. And osteocalcin was increased in case of being under standard level, but wasn't changed in case of normal level. Therefore these trial compounds can be used as a funcdonal diet for type I osteoporotic patients or preventive measures.

• 수산해양기술연구
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• 제41권4호
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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.

• 수산해양기술연구
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• 제52권4호
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• pp.356-363
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• 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.