• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.261-269
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• 1997

The autoxidation of cholesterol and lipid was investigated in mackerel during its salting for 50 days. Furthermore, the effects of antioxidants such as ascorbic acid and BHA on their autoxidation were studied. The cholesterol of mackerel during salting was continuously decreased. Its content was quantified by 23.3mg/100g in salted control sample after 50 days and that is only about 33% of total cholesterol content in fresh mackerel. The addition of BHA in mackerel during salting inhibited cholesterol oxidation more effectively than ascorbic acid.7-Ketocholesterol, unique cholesterol oxidation products was detected in this experiment and malonaldehyde, one of lipid oxidation products, contineuosly increased in control sample all the salting days by the almost same pattern but in the additive samples of ascorbic acid or BHA by different patterns, respectively. BHA was more effective antioxidant against cholesterol and lipid autoxidation than ascorbic acid.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1070-1076
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• 1998

The processing conditions of low salt mackerel (Scomber japonicus) fillet was investigated, in which fresh mackerel was filleted, salted in brine until the expected salt concentration reached, dried with cool air (3 m/sec, $10{\sim}20^{\circ}C$), and finally packed individually in polyvinyl chloride film. Salting time and salt concentration of brine decided the final salt level penetrated into the fillet. As the final salt level was fixed to $0.8{\sim}1.0%, salting for $15{\sim}20 hours with 5% or 10% brine at $5^{\circ}C$ was enough to get that level of salt. Formation of histamine during salting was negligible. Changes in VBN, salt soluble proteins, and histamine formation of salted mackerel fillet during the storage occurred more rapidly in cases of storage at $5^{\circ}C than af $-2^{\circ}C and $-20^{\circ}C. Oxidation of lipid during the storage progressed, however it was delayed longer then 100 days in case of storage at $-20^{\circ}C. Addition of sodium erythrobate or ginger extracts could provide some extent of browning retardation. The shelf-life of the salted mackerel fillet based on panel scores of brown color and rancidity appealed to be 14 days when stored at $5^{\circ}C, and more than 28 days in case of storage at $-2^{\circ}C and about 3 months stored at $-20^{\circ}C.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.79-90
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• 2018

Fish ages are critical information in fish stock assessments because they are required for age-structure models such as virtual population analysis and stochastic catch-at-age models, whose outputs include recruitment strengths, a spawning stock size (abundance or biomass), and the projection of a fish population size in future. However, most countries other than the developed countries have not identified ages of fish caught by fisheries or surveys in a consistent manner for a long time (e.g.,>20 years). Instead, data about fish body sizes (e.g., lengths) have been well available because of ease of measurement. To infer age compositions of fish in a target group using fish length data, we intended to improve the length frequency analysis (LFA), which Schnute and Fournier had introduced in 1980. Our study was different in two ways from the Schnute and Fournier's method. First we calculated not only point estimates of age compositions but also the uncertainty in those estimates. Second, we modified LFA based on the von Bertalanffy growth model (vB-based model) to allow both individual-to-individual and cohort-to-cohort variability in estimates of parameters in the vB-based model. For illustration, we used data about lengths of Korean mackerel Scomber japonicas caught by purse-seine fisheries from 2000-2016.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.6-12
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• 1988

To improve the individual packaging method and extend the shelf life of mackerel (Scomber japonicus), salted and unsalted mackerel fillets were packaged in laminated plastic film bag (Nylon/PE: $20{\mu}m/40{\mu}m,\;12{\times}15$ cm) filled with $CO_2$ gas, in vacuum, and stored at O and/or $5^{\circ}C$. The other samples were packaged in plastic foam trays, overwrapped with oxygen permeable film (control), and stored at same temperature. Volatile basic nitrogen (VBN), trimethylamine (TMA), histamine (HM) and viable cell counts (VCC) were progressed with the increasing of storage time, but thiobarbituric acid (TBA) values decreased gradually after reaching at a maximum peak in 5-9 days. Judging from 4 chemical components, VBN was the most available component in quality judgement of mackerel fillets and its upper limiting content was 25 mg%. Regression equation for shelf life prediction of mackerel fillets with sensory evaluation and VBN component was determined.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.191-198
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• 1982

Histamine has been known to be one of the causative materials of allergy-like food poisoning from the dark-fleshed fishes. In the early stage of spoilage, the dark-fleshed fishes have been known to be accumulated the level of 100mg/100g associated with outbreak of allergy-like poisoning. The present paper was conducted to elucidate the changes of histamine content in the canned boiled dark-fleshed fishes, such as common mackerel, Scomber japonicus, and sardine, Sardinops melanosticta, under different condition of processing and storage. Additionally, histamine content was determined in the canned boiled common mackerel, sardine and mackerel pike purchased from the supermarket. The results summarized are as follows : Changes of histamine content during storage of the canned fishes were nearly not found. The both factors of the storage time and temperature were not to the histamine content. Histamine was detected in concentrations of 7.24 to 14mg/100g in the canned sardine, 11.38 to 28. 8mg/100g in the common mackerel, and 13.88 to 21mg/100g in the canned mackerel pike purchased from the supermarket. The amount of histamine in the canned dark-fleshed fishes is less than that of inducing allergy-like food poisoning, and from the viewpoint of food hygiene these canned fishes are assessed to be safe.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.2
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• pp.153-165
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• 1995

The fluctuations of catches in set nets around Kyeongbuk Province, the eastern coast of Korea, were analyzed and investigated by on the values of CPUE(Catch Per Unit Effort per hauling), and composition of dominant species caught from 1985 to 1989. Annual CPUE values were fluctuated every year, but their trends were decreased year by year, When the values were evaluated by species, the trends of annual catches were shown decreasing in file fish(Auteridae), mackerel(Scomber japonicus), tuna(Thunnus Thynnus), rock fish(Sebastes schlegelid) and yellowtail(Seriola quinqueradiata), increasing in sardine(Sardinops melanosticta), jack mackerel(Trachurus japonicus), and herring(Clupea pallasi), and similar in squid(Todarodes pacificus) and cuttle fish(Sepiidae). The main fishing season evaluated by monthly CPUE was estimated from August to November with a little difference by regions : from August to November at Chukpyon and Kanggu, from September to November at Chuksan and Kampo, and August to December in Hupo. When the DPUE values were analyzed by species, the main fishing seasons were quite different by species. Mackerel, jack mackerel, tuna, yellowtail, and rock fish were caught mainly from September to October, file fish and squid from November to January, sardine from April to May, herring in May, and cuttle fish in April. Annual catches were shown highest level in file fish and revealed higher by sardine, jack mackerel, mackerel, squid, tuna, and yellowtail in order. But the highest catches among each species were different with seasons, and that from January to July was sardine, from November to December file fish. The main migrating seasons of file fish, mackerel, squid, tuna, and cuttle fish at Chukpyon were a little earlier than at other regions. Though the migrating seasons of jack mackerel and tuna were almost same in every regions, that of sardine were shown 3 month's difference according to regions. In the year when the warm currents were stronger than those of the normal year and their isotherms were formed from the north to south along the eastern coastal line, the annual fish catches in set net were show higher levels.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.4
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• pp.311-320
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• 1997

We selected horse mackerel Trachurus japonicus, mackerel Scomber japonicus and arrow squid Todarodes pacificus, to be used in the experiment. These fishes migrate to the Cheju coast and were caught by set-net. We studied on the attracting effect and the leading effect on the fish school using incandescent lights in an outdoor water tank at the Marine Research Institute Cheju National University. The results obtained are summarized as follows; 1. The horse mackerels, mackerels and arrow squids were actively attracted to the incandescent light. The optimum illumination and the reactions of each fish school were different though. 2. We turned the first attracting lamp on and turned it off after ten minutes. Then we turned the second attracting lamp on and turned it off after another ten minutes. The reaction of each fish school was a little bit different, but it worked to lead them to their destination. 3. We turned the three attracting lamps on at the same tune. After ten minutes, We turned the first attracting lamp off. After another ten minutes we turned the second attracting lamp off. The reaction of each fish school was a bit different, but it worked to lead them to their destination. 4. One incandescent light was moving. The reaction of each fish school was a little bit different, but it worked to lead them to their destination.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.273-288
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• 1991

To elucidate the physiological and biochemical differences between chondrichthyes and osteichthyes, the properties of the specific digestive enzymes in cat-shark, Cephaloscyllium umbratile, and mackerel, Scomber japonicus, were studied. Homogenous trypsin proved through the disc-electrophoresis, SDS-PAG electrophoresis and gel filtration was obtained from the pancreas of cat-shark by $50-70\%$ saturated ammonium sulphate fractionation, DEAE-Sephadex A-50 column chromatography, benzamidine-Sepharose 6B affinity chromatography and Sephadex G-75-120 gel filtration. Two types of trypsins were also obtained from the pyloric caeca of mackerel by $30-70\%$ saturated ammonium sulphate fractionation and the slightly modified procedure from the method adopted in the purification of cat-shark trypsin. The two trypsins, designated trypsin A and B, were proved their homogeneity by disc- and SDS-PAG electrophoresis and gel filtration. The molecular weights of the trypsins were estimated to be 31,700 for cat-shark trypsin, 30,000 for mackerel trypsin A and 29,000 for mackerel trypsin B by SDS-PAG electrophoresis, but those were estimated to be 21,500 for cat-shark trypsin, 23,700 for mackerel trypsin A and 21,500 for mackerel trypsin B by gel filtration. The trypsins exhibited their optimum conditions at pH 9.0 and on temperature ranged from $45^{\circ}C\;to\;50^{\circ}C$ for cat-shark, and at pH 8.0 and a temperature of $50^{\circ}C$ for mackerel trypsin A and B, respectively. The cat-shark trypsin was stable at pH 10.0 and the temperature below $10^{\circ}C$, whereas the mackerel trypsin A and B, were stable in the range over pH 7.0 to pH 9.0 below $10^{\circ}C$ and at pH 8.0 below $35^{\circ}C$, respectively. The mackerel trypsins were severely inhibited by some heavy metal ions such as $Ag^{2+},\;Cu^{2+}\;and\;Hg^{2+}$ compared to cat-shark trypsin. All of the enzymes were also inhibited by antipain, leupeptin, TLCK(tosyllysine chloromethyl ketone) and SBTI(soybean trypsin inhibitor) remarkably. The inhibitory effects of PMSF(phenylmethane sulphonylfluoride), DFP(diisopropyl fluorophosphate) and benzamidine were indicated that these enzymes belong to serine-proteases.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.37-46
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• 2004

In order to increase fishing efficiencies of the fyke net used in the coast of Jeju Island, water tank experiment was caried out entering and escaping behavior using nets that were reduced to 1/20 of the size of the full scale fyke net and were improved to have antrance structure, and mackerel Scomber japonicus as experimental fish. The results of measurement are as follows : 1. Fish school behavior in the main net was showed two different patterns : swimming in a circle in the right space of the main net and swimming back and forth in ellipse in the right and left space. 2. The swimming speed of mackerel school was 23.9. 12.6 and 32.0cm/sec in the center space, right space of main net and in the mouth 3. The entering rate of fish school was 40% in net with 35cm length of the upper and funnel net in the mouth of fyke model net and 49% in conventional type fyke model net. 4. The escaping rate of fish school was 10% in net with 35cm length of the upper and funnel net in the mouth of fyke model net and 69% in conventional type fyke model net. 5. The remain rate of fish school was 90% in net with 35cm length of the upper and funnel net in the mouth of fyke model net and 31% in conventional type fyke model net.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.521-528
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• 1986

In this paper, proteolytic activity of the tissue extracts from the internal organs such as alimentary canal, pancreas, pyloric caeca, stomach, liver and spleen of mackerel, Scomber japonicus, and sardine, Sardinops melanosticta, was compared with each other under the optimum reaction condition. The proteinases distributed in alimentary canal, pancreas, pyloric caeca and spleen were active in alkaline pH range, but those in stomach were shown the activity in acid pH range, furthermore those in liver were exhibited the activity in acid, neutral and alkaline pH range. The proteinases distributed in the internal organs of both fish were stable at the heat treatment of $45^{\circ}C$ for 5 minutes. The proteinases from stomach and pyloric caeca of the two fish and those from pancreas of sardine were less stable than those from any other internal organs of both fish. Whereas the proteinases from spleen and neutral proteinases from liver were shown to be stable by the heat treatment at $55^{\circ}C$ for 5 minutes. The proteinases from pyloric caeca of both fish, and stomach, pancreas and spleen of mackerel were stable during the whole storage days at $5^{\circ}C$, but the other proteinases were slowly inactivated after 14 days of storage. The enzymes were seemed to be more stable in the storage at $-15^{\circ}C$ than at $5^{\circ}C$.