• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.458-464
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• 1993

In the present paper enzymatic properties of the trypsins from the four dark fleshed fish were compared with each other and thermal stabilities of the enzymes were also investigated. The trypsins from the dark fleshed fish showed their activity only in BA-p-NA substrate of the amide substrates such as BA-p-NA and SP-p-NA, and BAEE and TAME of the ester substrate such as ATEE, BAEE, BTEE, and TAME. The enzymes were strongly inhibited by the serine protease inhibitors such as antipain, leupeptin, TLCK, DFP and SBTI, and were also inhibited by such metal ions as Cu$^{2＋}$ and Hg$^{2＋}$, but fairly activated by $Mg^{2＋}$. Denaturation constants of the enzymes were 13.4$\times$10$^{-4}$ sec$^{-1}$ for anchovy trypsin, 47.18$\times$10$^{-4}$ sec$^{-1}$ for mackerel trypsin A, 34.06$\times$10$^{-4}$ sec$^{-1}$ mackerel trypsin B, 42.28$\times$10$^{-4}$ sec$^{-1}$ for yellowfin tuna trypsin and 16.6$\times$10$^{-4}$ sec$^{-1}$ for albacore trypsin at 55$^{\circ}C$. The activation energies of the trypsins at a temperature range of 3$0^{\circ}C$ to 5$0^{\circ}C$ were estimated to be 13.91 ㎉/mole for anchovy trypsin, 11.61㎉/mo1e and 8.43㎉/mole for mackerel trypsin A and for mackerel typsin B, 4.35㎉/mole for yellowfin tuna trypsin, and 3.76㎉/mole for albacore trypsin.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.1
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• pp.24-32
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• 1996

This paper described on relation between the catches of tuna and the distribution of water temperature of eastern fishing ground of Tropical region in the Pacific Ocean. The data of catches and water temperature used in this paper were based log book which # 27 CHENG RONG(Gross tonnage : 399 ton) had been worked eastern fishing ground(Lat : 09$^{\circ}$N- 14$^{\circ}$S, Long : 115$^{\circ}$- 149$^{\circ}$W)from January to October, 1991. The obtained result are as follows : 1. On the relation between the catches and the geographical distribution, bigeye tuna was higher catches at Lat 4$^{\circ}$- 9$^{\circ}$N, Long 135$^{\circ}$- 139$^{\circ}$W area in the equatorial counter current region where surface water temperature was range of 27.5$^{\circ}C$ to 27.9$^{\circ}C$, yellowfin tuna was higher catches at Lat 4$^{\circ}$- 9$^{\circ}$S, Long 145$^{\circ}$- 149$^{\circ}$W in the south equatorial current region where surface water temperature was range of 28.$0^{\circ}C$ to 28.4$^{\circ}C$ and albacore tuna was higher catches at Lat 10$^{\circ}$- 14$^{\circ}$S, Long 120$^{\circ}$- 124$^{\circ}$W area in the south equatorial current region where surface temperature was range of 26.5$^{\circ}C$ to 26.9$^{\circ}C$ 2. On the relation between catches and distribution of vertical water temperature, bigeye tuna was higher catches at the water temperature of 1$0^{\circ}C$ to 12$^{\circ}C$ on depth layer between 300m and 360m, yellowfin tuna was higher catches at the water temperature of 15$^{\circ}C$ to 19$^{\circ}C$ on depth layer between 180m and 280m and albacore tuna was higher catches at the water temperature of 12$^{\circ}C$ to 14$^{\circ}C$ on depth layer between 280m and 310m. Above the result, it seemed that bigeye tuna distributed deeper layer than yellowfin and albacore tuna.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.246-255
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• 1996

To develop a natural antioxidative peptide, the gelatin was extracted from fish (Yellowfin sole) skin by hot $water(50^{\circ}C)$ extraction method and hydrolyzed with Alcalase, pronase and collagenase through a continuous 3-step membrane reactor. Each step enzymatic hydrolysates were determined the antioxidative activity and their synergistic effects, compared with $\alpha-tocopherol$ and butylated hydroxytoluene (BHT). Also, we tried to investigate the antioxidative disposition of peptide which was successfully separated by gel filtration, ion-exchange chromatography, and HPIC in cultured rat hepatocytes intoxicated with tert-butyl hydroperoxide (TBHP). Second step enzymatic hydrolysate (SSEH) among all hydrolysates and $\alpha-tocoperol$ was showed the strongest antioxidative activity. The optimum concentration of antioxidative activity for SSEH was $1\%(w/w)$ in linoleic acid. The synergistic effects were increased in using the hydrolysate with tocopherol and BHT. In the presence of the peptide isolated from SSEH, supplemented hepatocytes exposed to TBHP showed that delayed cell killing and decreased significantly the lipid peroxidation, compared with hepatocytes not cultured with isolated peptide.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.5
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• pp.309-315
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• 2005

Changes of sex steroid hormones in the plasma of yellowfin goby, Acanthogobius flavimanus were investigated in relation to the gonadosomatic index (GSI), the hepatosomatic index (HSI) and gonadal development. The GSI in females rose rapidly in November and remained high from December to May $(7.26\pm0.89­6.62\pm0.02)$. The Male's GSI also increased gradually from November and was highest in May $(0.16\pm0.08)$. The HSI in both sexes was in reverse correlation with the GSI, and the HSI was low during the spawning season (February-May). In females, the $estradiol-17{\beta}\;(E_2)$ level increased during vitellogenesis (November and December) and reached its maximum $(8.13\pm2.87 ng/mL)$ at the maturing period, in January. $17{\alpha},\;20{\beta}$-dihydroxy-4-pregnen-3-one$(17{\alpha}20{\beta}OHP)$ gradually increased from October $(0.063{\pm}0.02ng/mL)$ to March $(0.16{\pm}0.02ng/mL)$ and increased rapidly in May. The level of testosterone (T) showed a similar tendency of $E_2$. In males, T increased gradually during spermatogenesis from September to December $(0.14{\pm}0.06­0.26{\pm}0.10ng/mL)$ and peaked in January $(0.36{\pm}0.29 ng/mL)$ when the spermatozoa filled the testis. 11-KT also rose markedly in January and then decreased. On the other hand, $17{\alpha}29{\beta}OHP$ in males did not show any clear tendencies.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.102-111
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• 2010

This study was conducted to investigate the optimal conditions of collagen extraction from scales of yellowfin tuna (Thunnus albacares) using surface response methodology. Four independent variables of NaOH concentration and pretreatment fime in alkali pretreatment and enzyme concentration and treatment time in enzyme hydrolysis were used to predict a model equation for the collagen yield. The determinant coefficient ($R^2$) for the equation was 0.906. The values of the independent variables for the maximum yield were 0.32 N NaOH, 16.38 h alkali pretreatment time, 0.18% enzyme concentration, and 31.02 h enzyme treatment time. In the physicochemical properties of tuna scale collagen, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of tuna scale collagen showed the same migration distances as that of calf skin collagen. The amide A, I, II, and III regions of tuna scale collagen in Fourier transform infrared measurements were shown in the peaks of 3,414 $cm^{-1}$, 1,645 $cm^{-1}$, 1,553 $cm^{-1}$, and 1,247 $cm^{-1}$, respectively. The amount of imino acids in tuna scale collagen was 18.97% and the collagen denaturation temperature was $33^{\circ}C$. The collagen solubility as a function of NaCl concentration decreased to 4% NaCl (w/v) and the collagen solubility as a function of pH was high at pH 2-4 and sharply decreased from pH 4 to pH 7. Viscosity of the collagen solution decreased continuously until $30^{\circ}C$ and this decreasing rate slowed in the temperature range of $35-50^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.161-172
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• 1969

Ten experimental tuna long line fishing operations were performed with the long lines A and B, in combination casting orders of BA and AB. The long line B differs from A in its additional main line length per basket and its greater depth of submersion (Table 1). The BA casting order results in an AB hauling order, so that the long line B is casted at an earlier time of a day and fishes for a longer period than A line (fig. 2). The number of fish caught was divided into subclasses in order to be subjected to $x^2-tests$ (Table 2). The first series of $x^2-tests$ were calculated using the hooking rates of two subclasses with other factors pooled (Table 3). The second series of $x^2-tests$ were calculated to obtain the interactions between two subclasses when other factors differed (Table 4). Attention was paid to the extremely small interactions as well as to the large interactions in order to find out whether a factor functions in the same way or in a contradictory way when the other factors involved differ. The test result is summarized in Table 5. The relationship between the hook casting time (relative to the sunrise time) and the hooking rates reveals the feeding behavior of particular species (fig. 3) A high hooking rate for yellowfin tuna shown in the period from one hour before sunrise to the moment of sunrise suggests that they feed actively in that period. Their poor hooking rate on earlier casted hooks suggests that they do not feed well under conditions of darkness and that they feed best while the hooks are sinking. Furthermore it is likely that yellowfin tuna maintain a shallow depth in the daytime, for the $x^2$ interaction between the line casting order BA and AB shows their persistant preferance of the long line A regardless of line casting order. Bigeye tuna show their feeding behavior under conditions of darkness, and show a preference for the sea's deeper layer. Alepisaurus borealis (Gill) show their feeding behavior under conditions of darkness more significantly than the bigeye tuna and their preferance for deep layers is also more significant. Marlins (mainly Makaria mazara) show a feeding behavior which is similar to the yellowfin tuna. The author emphasizes that certain variations of the hooking rates in relation to the line easting time were caused by an inadequate fishing depth as well as by the fish preference for a particular feeding time. When the part of the line casted in pre-dawn hours and hauled in the pre-sunset hours show a significantly lower hooking rate than other parts of the line, then it is concluded that tile hooks settled in a sea layer too deep for feeding.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.87-93
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• 2008

To assess effects of contaminants on fish in Nakdong river, feral yellowfin goby Acanthogobius flavimanus were caugt in two different sites and its hepatic monooxygenase enzyme, including cytochrome P450 (CYP), NADPH-cytochrome P450 reductase (P450R), NADH-cytochrome b5 reductase (b5R), ethoxyresorufin deethylase (EROD), glutathione S-transferase (GST) were quantitatively determined. Gonadosomatic index (GSI), hepatosomatic index (HSI) and three sex steroid hormone (17$\beta$-estradiol, E2; testosterone, T; 11-ketotestosterone, 11-KT) levels of the fish were also investigated. HSI of fish from polluted site (site 1) were significantly higher than that of unpolluted site (site 2), but GSI levels were significantly lower in polluted site. No significant differences in plasma 11-KT and T levels were observed in two sites surveyed. E2 level was, however, significantly (p<0.05) higher in female fish from site 1 than site 2. In addition, hepatic EROD activity and CYP level of site 1 fish were lower than those of site 2 fish, whereas relatively high levels of P450R, b5R and GST activities were found in site 1. The results imply that yellowfin goby, especially female fish in Nakdong river estuary are affected from contaminants disrupting sex steroid hormone system.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.495-495
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• 2003

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.150-160
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• 1988

Food habits of Alaska plaice, Pleuronectes quadrituberculatus, and ecological interactions of this species with yellowfin sole, Limanda aspera, and rock sole, Lepidopsetta bilineata, in the eastern Bering Sea were studied. Alaska plaice mainly feed on polychaetes regardless of sex and size of fish. However, it was shown that food differed by sampling area. Feeding did not occur at night. Food competition seems to be negligible among the three shallow water fiatfish species inhabiting the eastern Bering Sea due to differences in food spectra or spatial distribution.

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