• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.3
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• pp.423-431
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• 2020

This study was conducted to investigate in vivo and in vitro digestibility in juvenile Atlantic Bluefin tuna Thunnus thynnus. In vivo digestibility was compared between four experimental diets to determine the optimum dietary inclusion level of an enzyme-treated sardine fish meal (EFM) and sardine fish meal (FM). The experimental diets were as follows; EFM75 (75% EFM), EFM60 (60% EFM and 15% FM), FM75 (75% FM) and SL (frozen sand lance) as a raw fish feed. Feces of Bluefin tuna (90.3 g) were collected both by siphoning from a 700 L cage and by dissection in 69 ton concrete rearing tanks. For the siphoning method, protein digestibility was higher in the tuna fed SL diet than that of other groups. The lowest protein digestibility was observed in FM75. For the dissection method, protein digestibility was higher in tuna fed EFM75 diet than that of other groups. The lowest protein digestibility was observed in the EFM60 group. In vitro digestibility was compared in six protein sources to find an alternative source of EFM for the tuna feed. The highest in vitro digestibility was observed in EFM (92%) followed by low temperature FM (72%), meat meal (65%), feather meal (60%), sardine fish meal (57%) and poultry by-product meal (55%).

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.305-310
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• 2009

This study was carried out to evaluate the use of fermented skipjack tuna viscera (FSTV) as an alternative for fish meal in juvenile olive flounder (Paralichthys olivaceus) diets. Lactobacillus bulgaricus was used as a starter for fermentation of skipjack tuna viscera. Four isonitrogenous (49% crude protein) and isocaloric (4 kcal/g DM) diets were formulated to contain graded levels (0, 5, 10, and 15%) of FSTV. Each experimental diet was fed three replicate groups (40 fish per tank) of juvenile flounder (average weight, $3.3\pm0.2$ g) for 5 weeks. At the end of feeding experiment, inclusion of FSTV up to 15% in diets did not affect survival rate (%) and weight gain of fish. Feed efficiency, protein efficiency ratio, protein and lipid retentions of fish fed the diet containing 10% FSTV were higher than those of fish fed the control diet (P<0.05). The values of fish fed the diet containing 15% FSTV were not different from those of fish fed other diets. Whole body lipid content of fish fed the diet containing 10% FSTV was higher than that of fish fed the diet containing 15% FSTV and control diet. The present results indicate that fermented skipjack tuna viscera could partially replace fish meal in juvenile flounder feed, and the inclusion of 10% FSTV may be efficient in improving the feed utilization of fish.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.237-241
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• 1999

It was investigated that the condition of fishing ground gave what kind of effect school type in relation to the property for the target school after the vertical temperature profile and school type were observed when tuna purse seiner for tuna purse seine was operated in the western pacific Ocean around the equator between December 12, 1993 and January 26, 1994. The results are as follows;1. This study divided fish schools associated with drift objects, a one targeted-operation, and the pelagic migrating fish schools that are another one for the property. The total of 23 operations were complected including 6 that targeted fish schools associated with drift objects and 17 that targeted pelagic migrating fish schools. It was known that the main operation was conducted on pelagic migrating fish school.2. Average and standard deviation of the depth of the surface mixing layer was 86.0m and 13.8m for fish schools associated with drift objects. 61.6m and 13.0m for pelagic migrating fish schools, respectively. The average depth of the surface mixing layer of the pelagic migrating fish schools was lower when compared to the fish schools associated with drift objects however the concentration of standard deviation was higher than those fish schools associated with drifted objects. Accordingly, it was assumed that the effect of vertical temperature profile for pelagic migrating fish school was higher than the fish schools associated with drift objects.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.181-190
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• 2020

This study was conducted to estimate the optimum dietary DHA oil level and replacement level of enzyme treated fish meal (EFM) with sardine fish meal for juvenile Atlantic bluefin tuna Thunnus thynnus. Four diets were used: 1) EFM75 in which 75% EFM and 4% DHA oil were applied, 2) EFM60, with 60% EFM and 15% sardine fish meal, 3) DHA2 with 2% of DHA oil, and 4) SL as a raw fish feed. In a feeding trial, juvenile bluefin tuna (body weight 30.1 g) were randomly stocked into four experimental tanks (69 tones) and fed the experimental diets for 13 days. Fish weight gain was higher in the EFM75 and SL groups than in the DHA2 and EFM60 groups. The feed conversion ratio was lower in the EFM75 and DHA2 groups than in the EFM60 and SL groups. Survival was higher in fish fed the formulated diet groups (EFM75, EFM60 and DHA2) than in fish fed SL. This study clearly indicates that up to 10% dietary sardine fish meal can be used in juvenile T. thynnus diets, with an optimum dietary DHA oil level of approximately 3%.

• Fisheries and Aquatic Sciences
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• v.26 no.10
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• pp.593-604
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• 2023

Post-harvest handling and hygienic level of aquatic products significantly affect the quality and level of safety. Cold chain control is one of the determining factors for the quality of fish and the bacterial community that grows on the fish. Identification of spoilage bacteria and pathogens in aquatic products must be made because it will determine the physical and chemical quality. A molecular identification method with high sensitivity is the solution. This study aims to identify the quality of fish and bacterial communities that grow. The research procedures included sample collection, pH measurement, drip loss measurement, transportation and cold storage treatment, DNA extraction, DNA sequencing, sequence analysis, and bioinformatics analysis. The conclusion obtained from this study is that the simulation of the cold chain system applied to eastern little tuna does not significantly affect changes in the water activity value, pH, and drip loss. The insignificant change indicates that the eastern little tuna samples are still in good quality. The bioinformatics analysis showed the highest diversity and abundance of the bacterial community came from the Gammaproteobacterial class.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1417-1424
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• 2007

The food components of fish (skipjack tuna, yellowfin tuna, bluefin tuna, conger eel, salmon, Spanish mackerel, armored weasel-fish) frames and their hot-water extracts were investigated to explore their possibilities as resources for fish Gomatang. According to the results of volatile basic nitrogen and heavy metal, bluefin tuna and salmon frames were below the safety limits suggested by Codex Code. Thus, bluefin tuna and salmon frames appeared to be safe as basic ingredients for fish Gomtang. The major components of all hot-water extracts from fish frames were nitrogenous component. According to the results of extractive nitrogen and sensory evaluations of hot-water extracts from fish frames, the salmon frame was a good raw material as a basic ingredient of fish Gomtang. The calcium and phosphorus contents of hot-water extracts from salmon frame were 18.0 mg/100mL and 33.1 mg/100mL, respectively.

• The Journal of Fisheries Business Administration
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• v.18 no.1
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• pp.59-97
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• 1987

Tuna and tuna fishing extend over most of the tropical waters of the world oceans, especially, this study of the Indian Ocean and the fish and the fishing vessels are highly mobile. No country can deal in isolation with the problems of its tuna fishery and of any tuna fishery in its waters, without collaborating with other countries. This cooperation is often best established through some formal international mechanism. The essential requirements are for information-on the resources, the fishery, the trade-and to identify where management actions are needed to consore the resources or to maintain the economic or social function of the fishery. These will also usually require some form of international mechanism. With the changes in the Law of the Sea, the siuuation in respect of management of tuna-considered among the highly migratory species, requirng special treatment-has also changed. At present there are both uncertainty regarding tuna management and political arguments as to how such management can be best implemented. Bearing this in mind, together with the fact that only few tuna stocks have shown clear evidence of serious depletion through over-exploitation, present emphasis will be placed on information requirements. This study included compiling the data necessary to review the state of stoks in the Indian Ocean tuna fishing grounds. Information on the resources-where the fish are, their quantity, their movements, etc. is important, whether in planning development of new fisheries, or considering the need for collaboration with other countries (in ascertaining to what extent their catches may affect catches of the natoinal fleet) or for conservation measures. A major source of information is the statistics of for conservation measures. A major source of information is the statistics of catch and fishing effort from existing commercial vessels. These need to be assembled for all fisheries on the same stock on an oceanwide basis. The statistical data also need to be analysed and intepreted, and combined with biological data(e.g., on growth, mortality and migration rates) to provide information that is intelligible and useful for administrators and other decision-makers. This must also be undertaken on a resource-wide or ocean-wide basis. Finally, because of the world-wide similarities in the methods of datching, processing and marketing fish, there is a particular tut not exclusive need in those countries just beginning to develop their tuna fisheries-to have ready access to a syntheis of information on tuna, tuna biology and tuna fisheries and tuna fisheries economics and management on the Indian Ocean.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.419-426
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• 2008

Physicochemical characteristics of gelatin extracted from abdominal skin of yellowfin tuna (Thunnus albacares), were investigated by comparing its proximate composition, pH, amino acid composition, viscoelastic properties, gel strength and SDS-PAGE patterns, with those of bovine and porcine gelatins. The effects of gelatin concentration, maturation time, heat and freeze treatments on the gel strength of yellowfin tuna abdominal skin gelatin were studied. Amounts of $\alpha$-chains, $\beta$- and $\gamma$-components of yellowfin tuna abdominal skin gelatin were higher than those of the two mammailan gelatins. Yellowfin tuna abdominal skin gelatin had the lowest imino acids (proline and hydroxyproline) content, which was consistent with that of other fishes. However, yellowfin tuna abdominal skin gelatin was highest in glycine, alanine, and lysine. The gel strengths of all gelatins were proportional to the concentration of gelatin, but yellowfin tuna abdominal skin gelatin exhibited the greatest gel strength at each concentration. Yellowfin tuna abdominal skin gelatin required a longer maturation time than the two mammalian gelatins to form a firm gel. Higher heating temperature decreased the gel strength of yellow fin tuna abdominal skin gelatin more than in the two mammalian gelatins. Freezing decreased the gel strength of bovine gelatin only slightly, but longer freezing times resulted in greater reductions in gel strength in the yellowfin tuna abdominal skin and porcine gelatins.

• 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.