• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.2
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• pp.69-77
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• 2006

The aim of this study was to develope a fishing technology for fisheries management for improving the survival rate of young fishes escaped from trawl net. Sea experiments were carried out to investigate the survival rate of the fishes in off Geomun island and Korean southern sea. Cover-net fish cage was designed and manufactured to collect fishes escaped from COD(codend) and TED(trawl escapement device). Fish cage was installed in a shallow site where scuba diver can observe the surviving fishes after separating the cage from trawl net. Most of fishes except horse mackerel(Trachurus japonicus) and mackerel(Scomber japonicus) could escaped through TED(bar space 35mm) easier than COD(mesh size 54mm). Especially, escapement rate of redlip croaker(Pseudosciaena polyactis) escaped from TED was the highest as 73.9%. Survival rate of horse mackerel(Trachurus japonicus) escaped from TED was 85.5% at the point of 96 hours over, while the survival rate for COD showed a rapid decrease according to the time elapse as 85.0% at the point of 24 hours, 76.4% for 48 hours, 62.7% for 72 hours and 56.1% for 96 hours. Over 90% of red seabream(Pagrus major) and rock bream(Oplegnathus fasciatus) escaped from TED were survived 96 hours over and the survival rate of those fishes were excellent compared with the other fish species. All korean pomfret(Pampus echinogaster) escaped from both COD and TED were died within 48 hours. Most of redlip croaker(Pseudosciaena polyactis) were also died within 12 hours because of the weak physiological characteristics by water pressure change. Survival rate of fishes like as horse mackerel(Trachurus japonicus) having hard skin was high while it was low for the fishes like as squid(Todarodes pacificus) and hair-tail(Trichiurus lepturus) having soft skin. We could know that there were big differences in the survival rate offish species escaped from trawl net.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.125-130
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• 2012

We describe early morphological development in laboratory-reared specimens of the brown croaker, Miichthys miiuy, in relation to fin differentiation, head dimensions, and squamation. From the yolk sac stage to the flexion larval stage (a period of 12 days following hatching, at which time the larvae were <4.2 mm in total length; TL) we observed the presence of a fin-fold around the body, while the caudal fin appeared rounded and lacked scales. Rays developed in the dorsal, anal, and pectoral fins in a process that was almost complete in larvae 12 days, while ray segmentation occurred between 26 and 29 days of age. Elongation of the middle rays of the caudal fin was initiated at 32 days, and the rays were remarkably elongated by 37 days. By 68 days the caudal fin was lanceolated (50.7 mm TL). Scales began to develop from the midlateral lines of the caudal peduncle at 9.1mm TL (28 days), eventually encompassing the entire operculum (22.1 mm TL; 44 days). The head dimensions were largely stabilized at >12 mm TL (30 day).

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.1026-1031
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• 2003

The two-level full factorial and mixture design were used to screen ingredient type and to investigate effects of ingredients on properties of alkali surimi gel from frozen white croakers using measurements of a breaking force, deformation and color. The addition of starch decreased a breaking force and deformation of gel regardless of starch type. The breaking force was decreased, but a deformation was not significantly changed (p<0.05) with increasing starch level. The potato starch was more resonable than com and wheat starch for a breaking force and deformation. The bovine plasma protein (BPP) greatly improved a breaking force and deformation. The breaking force and deformation of gel were increased with concentration of BPP. The whiteness of gel was slightly improved with adding starch and non-muscle for all treatments. At 78% moisture, the optimum ratios of ingredients were 89.4∼90.0% for surimi, 5.9∼6.3% for potato starch and 5.0∼5.4% for BPP to obtain above 100g for a breaking force, 4.6 mm for a deformation, and 25.5 for a whiteness.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.199-204
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• 1995

The changes of nucleotide and their related compounds, TMAO, TMA and total creatinine content of mackerel, pacific saury, yellow croaker and brown sole were investigated on heating conditions. The results were as follows. The content of inosine was the highest in all fish commonly, and white muscle fish showed higher than that of red muscle fish. The content of hypoxanthine showed increase by heat treatment but other compounds showed decrease. The contents of TMAO showed 31.1, 26.2, 49.4 and 58.5 mg% in each sample of raw materials, and brown sole showed the highest content than other fishes and TMAO contents showed decrease by heat treatment. The contents of TMA showed 3.7, 5.8, 22.9 and 16.9 mg% in each sample, and pacific saury showed the highest content than other fishes but TMA contents showed increase by heat treatment. The contents of total creatinine showed 341.2, 469.8, 52.3 and 87.6 mg% in each sample, and red muscle fish showed higher than that of white muscle fish and the highest content was shown in yellow croaker. All fish species showed decrease in contents of flavoring by heat treatment.

• The Journal of Fisheries Business Administration
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• v.40 no.2
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• pp.105-126
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• 2009

This study applies the cointegration theory to analyse the causality of the prices between imported fisheries and domestic fisheries in distribution channel. We've focused on the prices of import, wholesale and retail about the frozen Alaska pollack, hairtail and croaker which take up high portion and are popular among most of the consumers. In process of analysis, the unit root test was adopted to find the stability of time series data prior to the cointegration test. If the time series data was found as stable one in unit root test, we should analyse the VAR model. If unstable, the cointegratioin test was adopeted to find the long-run equilibrium relationship between the data. When the long-run equilibrium relationship was found among the price of the import, wholesale and retail price, the VECM model was adoped. If not, the differenced VAR model was adopted. The main findings of this study could be summarized as follows ; First, according to the result of the analysis on VAR model, time series data of frozen Alaska pollack was found as stable and has causality relationship and close effect was existing among the import, wholesale and retail price. Second, the data of frozen hairtail was found as an unstable one in unit root test and the result of cointegration test showed the long-run equilibrium relationship at lag 1. From the results of VECM model, we could find that the coefficient of error correction is effective, and the sign is negative(-). It means that the existence of adjustment tendency to long-run equilibrium after a short-run deviation. But the short-run causality of the prices were not found except the price of wholesale. Third, according to the results of differenced VAR model, data from frozen croaker did not have the stability and long-run equilibrium. Moreover, it was found that the import price has a weak causality on the retail price. Because of having difficulties in collecting data, the result of this paper could not explain the relationship among the prices of import, wholesale and retail perfectly. However, it more or less contributed to a long-lasted debate on the direction of causality of price-setting in academic research and provided a useful guide for the policy makers in charge of the price-setting of fisheries products as well.

• The Journal of Fisheries Business Administration
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• v.35 no.1
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• pp.133-168
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• 2004

The purpose of this study is to examine the state and characteristic of seafood marketing in Korean West Coast during the colonial period ruled by Japan. To accomplish the purpose, we tried to set the fisheries statistical database by reviewing of $\boxDr$Statistical Annual Report of Chosun Chongdokbu$\boxUl$ and $\boxDr$Official Report of Chosun Chongdokbu$\boxUl$. A trend analysis was carried out with the data. Also, by reviewing of articles related to the state of seafood marketing via $\boxDr$Daehan Maeil Newspaper$\boxUl$, $\boxDr$Maeil Newspaper$\boxUl$ issued at the period, we could find out some meaningful findings which backed up the statistics in realistic facts. For numbers of businessman in seafood marketing, it was clear that the number of Japanese businessmen increased more quickly than that of Korean compared with other sphere of fisheries. That means Japanese grasped Korean seafood market in a short time. In price of seafood in terms of cities, Kunsan was comparatively higher than Incheon and Mokpo. In price of seafood in terms of species, ‘Snapper’ was mostexpensive, and ‘Mackerel Pike’, ‘Anchovy’, ‘Mullet’, ‘Eel’, ‘Flatfish’ followed in that order. In price of a species in terms of ‘Yellow Croaker’, which was famous in West Sea, ‘Croaker with salt’ was more expensive than dried and fresh one. For the transition trend of number of fish market, we could ascertain that the number of market increased until 1919, however, it decreased slowly from 1932. That means Japanese government went to war against China from 1931. Of the West Coast, the number of fish market in Chungnam province was most high, but that of Chonbuk outrun from 1940. At that time, the number of fish market in West Coast reached to 34% out of that of whole country. In 1919, the proportion of seafood sales amount of West Coast neighboring provinces, such as Kyunggido, Chungnam, and Chonbuk, was 23% of whole country which rose to 28% in 1929, and 29% in 1939. Therefore, we could assure that seafood marketing was very active at that time in the region. When we consider the trend of seafood export at the main ports of West Coast, in 1910's, the export through Mokpo and Inchon port was very live but that of Kunsan was very tiny. However, in 1920's, the export amount of Inchon port did not much change, but that of Mokpo decreased, whereas, that of Kunsan increased. In the early and middle of 1910' s which was around beginning of Japanese ruling period, we realized that the imperialist Japan was very eager in political efforts to enhance the mind of seafood's quality improvement through the opening of several fisheries competitive shows and fairs.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.224-231
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• 2018

Dietary niches can support the coexistence of sympatric species in marine ecosystems, which can lead to the presence of greater abundances of those species. Stomach contents of silver croaker (Pennahia argentata) and Japanese sillago (Sillago japonica) inhabiting the Nakdong River estuary, Korea were analyzed to determine diet compositions and the presence of any size-related and inter-specific feeding relationships. These species were bottom-feeding predators that consumed mainly benthic crustaceans and mollusks, but polychaetes were also important in the S. japonica diets. Non-metric multidimensional scaling (nMDS) ordination and multivariate analyses based on weight contributions of the different prey taxa to stomach contents revealed significant inter-specific dietary differences. Size-related change was also significant for P. argentata diets, but not for S. japonica. Canonical analysis of principal coordinate (CAP) ordination plot further demonstrated that differences in the type and range of prey ingested by the two species contributed such an inter-specific difference in the diet compositions. The results from this study provide clear evidence of niche segregation between co-occurring P. argentata and S. japonica in the Nakdong River estuary, which would reduce the likelihood of inter-specific competition for food resources.

• Journal of Life Science
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• v.31 no.3
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• pp.314-320
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• 2021

In the present study, we investigated the effect of photoperiod and water temperature on the gonadosomatic index (GSI), histological stage of the testes, and plasma levels of sex steroid (testosterone, T; 11-ketotestosterone, 11-KT) hormones in cultured male small yellow croakers (Larimichthys polyactis). In a photoperiod experiment, small yellow croakers were reared under a natural photoperiod (NP, 10L:14D-11L:13D), long photoperiod (LP, 14L:10D), and short photoperiod (SP, 10L:14D) at 17℃ for 90 days. The GSI was significantly higher in the LP group than in the other groups at 30 and 60 days. The plasma 11-KT levels were significantly higher in the LP group than in the other groups at 30 days. In a water temperature experiment, small yellow croakers were reared under natural water temperature (NT, 19.1-15.0℃), or at 17℃, 21℃, or 25℃ under a LP (14L:10D) for 60 days. The GSI was significantly lower for the 25℃ group than for the other groups at 30 and 60 days. The plasma 11-KT levels were significantly lower for the 25℃ group than for the other groups at 60 days. Therefore, the sexual maturation of cultured male yellow croakers was promoted by LP and inhibited at water temperatures above 25℃. These findings suggest that the sexual maturation of cultured male small yellow croakers is controlled by both the photoperiod and the water temperature.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.1
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• pp.25-33
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• 1982

The secular fluctuations of catches and fishing grounds and their relations to the bottom temperature are examined by using data of catches of the Yellow Croaker and the Kang-dal-li by stow net in the Yellow Sea and the East China Sea during recent ten years, 1970-1979. The phase of the secular fluctuations of the catches was delayed about two years to that of during 1974-1975, and thereafter were balanced up to the end of 1976. However, after 1976, such tendency was not distinct because of an increase in fishing efforts. The fishing ground in 1977, in which temperatures were lower than other years, was found in the southern part of the fishing grounds of warmer years, for example, 1972.

• Conservation Science in Museum
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• v.2
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• pp.51-55
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• 2000

This study is an analysis of residual fatty acid of the unidentified 26 fish bone samples which were excavated from Bupchon-ri in Wonju, Kangwon province. The purpose of this study is to identify fish kind by comparing the residual fatty acid analysis with the reference data of croaker, shark, herring and weakfish. Fatty acid was separated by gas chromatography and distribution pattern was analyzed by calculating composition of each sample. Principal component analysis(PCA), one of multivariate analysis method was used to understand fatty acid distribution data.