• KSBB Journal
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• v.11 no.5
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• pp.518-523
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• 1996

The sensor to determine ATPase activities was consisted of an immobilized enzyme membrane(purine nucloside phosphoryrase and xanthine oxidase) and an oxygen electrode. The proposed sensor was used for the determination of $K^+-, Ca^{2}+- and Mg^{2+}-$ATPase activities in several fish muscle proteins such as Thunnus albacares(Yellowfin tuna), Tetrapturus audax(Striped marlin), Prognichthys agoo(Japanese flyingfish), and Cypvinus carpio(Carp). $K^+-, Ca^{2}-$ATPase activities measured by the proposed sensor system were in good agreement with the results obtained by a conventional colorimetric assay. One cycle of assay could be completed within 3mlnutes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.6
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• pp.944-947
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• 1997

Docosahexaenoic acid (DHA) rich oil was obtained from blue fin tuna (Thunnus thynnus orientalis) orbital tissue with centrifugation of 12,000 rpm under vaccum $(10^{-1}\;Torr)\;at\;4^{\circ}C$. The effect of DHA rich oil (DHA content; $27.8\%$) on $CCl_4-induced$ acute injury was investigated biochemically and histopathologically. Dosage of DHA rich oil on 24h before $ CCl_4-administration$ prevented significantly the increase of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GTP) values. No necrosis of hepatocytes was observed in rat livers treated with DHA oil on 24h prior to $CCl_4-administration$. These results suggested that DHA oil controls the accumulation of fat in the liver and prevented the liver injury.

• Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.1.1-1.12
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• 2018

Pacific bluefin tuna (Thunnus orientalis) is one of the commercially important species in Korea as well as other countries of the North Pacific. Korean offshore large purse seine fisheries targeting small pelagic fishes such as chub mackerel have caught T. orientalis temporarily in the east of Jeju Island. The catch of T. orientalis in March through June occupied approximately 60% of the total. The monthly catch around Jeju Island from 2004 to 2013 showed a negative correlation (r = - 0.755, p < 0.01) with the seawater temperature at 50 m and had a significant positive correlation (r = 0.856, p < 0.01) with the Pacific Decadal Oscillation Index (PDOI). The highest catch and catch per unit effort (CPUE) of T. orientalis around Jeju Island occurred either when the seawater temperature ranged between 15 and $16^{\circ}C$ at 50 m or when the catch was taken near the frontal area where two water masses from offshore and coastal areas collide. The length of T. orientalis caught around Jeju Island from 2004 to 2013 ranged from 19 to 193 cm in fork length (FL). The time series of the monthly mean FL of T. orientalis had a negative correlation (r = - 0.592, p < 0.01) with the seawater temperature at 50 m and had a significant positive correlation (r = 0.668, p < 0.05) with PDOI.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.2
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• pp.116-123
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• 2018

Pacific bluefin tuna (Thunnus orientalis) has been mostly caught by the Korean offshore large purse seine fishery in Korean waters. The annual catch of Pacific bluefin tuna caught by the offshore large purse seine fishery in Korean waters showed less than 1,000 mt until the 1990s except for 1997. The catch sharply increased to 2,401 mt in 2000 and recorded the highest of 2,601 mt in 2003, but the catch has generally decreased with a fluctuation thereafter. The main fishing ground of Pacific bluefin tuna of this fishery is formed around Jeju Island. However, it expanded to the Yellow Sea, the coastal of Busan, and the East Sea, which depends on the migration patterns of Pacific bluefin tuna by season. The CPUE standardization of Pacific bluefin tuna was conducted using Generalized Linear Model (GLM) to assess the proxy of the abundance index. The data used for the GLM were catch (weight), effort (number of hauls), catch ratio of Pacific bluefin tuna, moon phase by year, quarter and area. The standardized CPUE from 2004 to 2011, except for 2003 and 2010, showed a steady trend, and then increased until 2014. The CPUE in 2015 decreased, and in 2016 was higher than that in 2015. The result of GLM suggests that the effect of the catch ratio of Pacific bluefin tuna is the largest factor affecting the nominal CPUE.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.740-746
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• 2010

This study standardized the catch per unit effort (CPUE) of bigeye tuna (Thunnus obesus) caught by the Korean longline fishery in the Pacific Ocean. The study used a general linear model (GLM) to standardize the CPUE using catch and effort data aggregated by year, month, and $5{\times}5$ degrees of latitude and longitude in the tropical Pacific Ocean from 1982 to 2008 (except for 1988 and 1989). Explanatory variables in the GLM analysis included year, month, subtropical area, and number of hooks between floats (HBF). The study area and HBF were subdivided into three subtropical areas and six classes, respectively. During the study period, the standardized CPUE was significantly related to the nominal CPUE. The standardized CPUE declined sharply, as compared to the nominal CPUE, after the mid 1990s. In particular, the decline in the standardized CPUE in all subtropical areas in the 2000s was clearer than that of the nominal CPUE.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.2
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• pp.125-134
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• 2023

The swimming behavior of pacific bluefin tuna (Thunnus orientalis) in the offshore sea cage of the brass fishing net was observed and analyzed by imaging sonar techniques. The cultured fish spent most of the time swimming a circular path along the circular cage wall and continued to swim only clockwise direction without completely changing the swimming direction during the 23-hour observation time. In addition, changed swimming behaviors were divided into four categories: (a) the behavior of a large group temporarily swimming in the opposite (counter clockwise) direction, (b) the behavior of a small group temporarily swimming in a small circular path, (c) the behavior swimming small circular path in the center of the cage, and (d) the behavior of a large group swimming across the center of the cage. The maximum swimming speed of the cultured fish was from 3.5 to 3.8 TL/s, the mode was from 1.2 to 1.4 TL/s and the swimming speed during the day time was faster than at night time. It was confirmed the cultured fish swam not only on the surface but also near the bottom net of the cage during the day, but swam mainly at the upper part of the cage at night.

• 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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.225-231
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• 1991

In order to suggest the useful information on the fishing ground of the bigeye tuna Thunnus obesus(LOWE), a data base system was formed with catch data of the Korean tuna long liners during from 1975 to 1987 by using a set of 16 bits personal computer. This data base was constructed of the handling program and 4 types of data file processed from the monthly and yearly catch data of the whole tunas and the bigeye tuna. And when the system was started, the map of one among various Oceans such as the Pacific, the Atlantic and the Indian Ocean. is drawn on the monitor. And then the catch rates of the whole tunas or the catch ratios of bigeye tunas are indicated by the figured symbols and the colors on the sea divisions of 5$^{\circ}$ space of longitude and latitude respectively at the same time. Also this system has the preestimating program on the catch rates of the whole tunas and the bigeye tuna in the desired month and sea divisions. In the results than this data base system was handled and tested, very useful informations were obtained for the detection of tunas, especially bigeye tuna, and the preestimation was possible in a desired level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.363-372
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• 2023

This study was developed to prepare hamburger steak (HS), wantang soup (WS), and tomato soup (TS) for senior-friendly seafood's (SFS) using bigeye tuna Thunnus obesus, and to investigate their quality characteristics. All data were presented in the order of HS, WS, and TS. The hardness values were 298.9×1.0³, 47.1×1.0³ and 14.9 ×1.0³ N/m², respectively. The viscosity of TS was 2,856 mPa·s. The protein contents were 13.8, 11.7, and 9.7 g/100 g, respectively. The fat-soluble vitamins content were as follows: vitamin A 21.88, 5.03, and 23.72 ㎍RAE/100 g; vitamin D 1.15, ND, and 1.81 ㎍/100 g, respectively. The water soluble vitamins contents were as follows: vitamin C 47.22, 32.83 and 37.01 mg/100 g; vitamin B₂ 0.17, 0.11 and 0.10 mg/100 g; vitamin B₃ 34.87, 34.76 and 54.62 mgNE/100 g. The Ca contents were 15.9, 16.8, 28.9 mg/100 g, and the K contents were 383.8, 167.4, and 300.0 mg/100 g, respectively. The dietary fiber was 0.04, 0.07 and 0.08 g/100 g, respectively. Escherichia coli was not detected in any of the products. These results suggest that the products should be classified as follows, based on their appropriateness as SFS: HS, WS and TS.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.206-211
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• 2002

The aim of this study was to obtain the basic data on the fish school behavior change to approaching vessel and fish species identification by means of their swimming speed. The surveys were carried out for the juvenile southern blue fin tuna and other fish schools off Esperance, western Australia from January to March 1999. We observed changes of fish school behavior in response to the approaching vessel using 360-degree scanning sonar. The results showed that, a horizontal direction index used to quantify a change of fish school behavior did not identify dependence of a radial distance and a swimming speed. A Mann­Whitney test conducted using the horizontal swimming speed of both species identified by sonar specialists, did not reveal a significant difference.