• Journal of fish pathology
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• v.11 no.2
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• pp.143-150
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• 1998

Characteristics and distribution of the natural commensal flora in the surrounding environment and tissues of clam in Hadong area were studied under varying conditions of growth media and incubation temperatures. Total numbers of bacteria present in intestinal tract, gill, body fluid and surrounding mud were found to be not influenced by the used BHIA, STA and SNA media. Although the growth rate of bacteria at the condition of $15^{\circ}C$ incubation temperature was slower than that of $25^{\circ}C$ and $35^{\circ}C$, it showed the highest number of total bacteria compared with other two different conditions of incubation temperature. Interestingly, the proportion of bacteria able to form colony on several selective media was higher in replica analysis from nutrient media to selective media than that in direct smearing from samples. The generic diversity of bacteria isolated from the tissues and analyzed by API 20E and API 20NE kit showed similar pattern with each other and distinct from that of environment. The distribution of bacteria in the surrounding mud or mantle fluid of clam indicated a high diversity comparable to that found for the gill or intestinal tract microflora, with Pseudomonas being the prevalent group. It implies that the tissues of clam may probide a selective habitat for a commensal microflora.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.9-18
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• 2016

Histological and morphological development of the digestive tract of sevenband grouper were observed from after hatching to 60 days. Fishes were fed with rotifer (Brachionus rotundiformis) and chlorella (Chlorella ellipsoidea) after hatching from 2 to 20 days rotifer and brine shrimp (Artemia salina) in after 20 days rotifer, brine shrimp and semi-dry artificial diet in after 23 days. Histological and morphological development of ten larvae was observed by paraffin embedding method after fixing in 10% neutral buffered formalin. Sevenband grouper RLG showed characteristics of carnivorous fish by average 0.87. Larvae after hatching can't open the mouth and anus digestive tract was observed in a straight line following yolk sac. Larvae was observed feeding activity by opening the mouth and anus. Metamorphosis started 8 days after hatching. Esophagus divided four layer, and goblet cell was observed in esophagus, mid intestine and rectum. Larvae started cannibalism and it was caused by difference of growth. The inside of stomach was differentiated to cardiac orifice, body of stomach, pyloric stomach, and pyloric caeca. Goblet cell was observed all intestine. Gastric gland differentiated after hatching 28 days in stomach. Secretion of gastric juice was found at stomach and mucosal fold pyloric caeca. Even thought the inside of stomach expended and the number of gastric gland increased consistently and goblet cell in intestine and mucosa became longer, histochemical changes follow couldn't be found during transforming juveniles 38 days after hatching.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.914-919
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• 1998

This study was conducted to evaluate the purification efficacy by filter and ultra violet (UV) irradiation against inlet and outlet seawater of the land based fish farm. Purification efficacies for inlet seawater (50$\ell$/min) has been examined with filter of 60$\mu$m pore size and UV irradiation at an average dose 0.5 mWS/$cm^2$ for 5 months. For outlet seawater filter of 90 $\mu$m pore size only was used. Temperature, salinity, pH, $NO_3-N,\;NO_2-N,\;NH_4-N,\;PO_4-P$, DO and COD of inlet and outlet seawater in the system were not influenced. However, the removing rate of suspended solid and turbidity of inlet seawater were appeared to be $48.7\~65.6\%$ (average $51.9\%$) and $33/3\~42/5\%$ (average $34.8\%$) after passing through screen filter respectively. Also, germicidal efficiency to the total bacteris and Vibrio species were $16.7\~20.2\%$ (average $19.2\%$) $20.0\~21.9\%$ (average $20.9\%$) respectively after passing through UV irradiation. After passing through drum filter of 90$\mu$m pore size, suspended solid and turbidity of outlet seawater were appeared to be $42.7\~52.6\%$ (average $46.9\%$), $27.7\~29.9\%$ (average $28.3\%$), respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.315-326
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• 1991

This study was tried for a mathematical approaches related to daily fluctuations in the stomach fullness of Agrammus agrammus. The specimen was collected by angling and gill net from September 1984 to August 1985 off Shinsudo, Samchonpo. Fullness of the stomachs was increased in the early morning and the late afternoon, decreased in the late morning, at noon, and during the night. That is, feeding activity of the fish was more intense at sunrise and sunset. Daily feeding activity of the fish in a day was divided into the time period of gastric evacuation and both feeding and gastric evacuation. Stomach fullness with the lapse of time in the time period of gastric evacuation was geometrically decreased. Stomach fullness in the time period of both feeding and gastric evacuation was affected by gastric evacuation rates, feeding rates, and maximum fullness of the stomach. These parameters were able to estimate from the method estimating the regression coefficient in the relationship between the time(t) and the stomach fullness$(F_t)$, or between stomach fullness at the time t and $t+\Deltat$. The rates of feeding and gastric evacuation were the highest in spring and the lowest in winter. The relationships between time(t) and stomach fullness$(F_t)$ in the time period of gastric evacuation and both feeding and gastric evacuation induced from hypotheses were respectively as follows. $$F_t=F_{to}e^{-r(t-to)}$$, $$F_t=F\infty-(F\infty-F_{to})e^{-(p+r)(t-{to})}$$

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.163-180
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• 1983

Fish larvae were collected from Changson channel, Namhae over the period from June 1982 to May 1983. A total of 44 species (33 families and 41 genera) were identified and described with morphological feature. The larvae of Cyclopsis tentacularis is newly reported in the Korean waters. Abundance of the species in numbers was as follows : Engraulis japonica $86.56\%$, Acanthogobius flavimanus $5.91\%$, Enedrias sp. $1.71\%$, Sebastes inermis $1.18\%$, Leucopsarion petersi $0.78\%$, Hexagrammos otakii $0.68\%$. According to variation of seasonal abundance the larvae were grouped into three seasonal groups as follows : Spring type: Engraulis japonica, Astroconger sp., Enedrias sp., Leucopsarion petersi, Sebastes inermis, Hexagrammos otakii Summer type : Engraulis japonica, Leiognathus nuchalis, Acanthogobius flavimanus, Omobranchus elegans, Syngnathus schlegeri. Winter type: Enedrias sp.

• Journal of Life Science
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• v.25 no.3
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• pp.269-275
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• 2015

Collagen peptides, which are found at high concentrations in the human body, are present in animal bones and the skin of marine organisms, namely, fish scales. Collagen is the most abundant structural protein of various connective tissues in animals. Furthermore, it is widely used in biomedical material, pharmaceutical, cosmetic, food, and leather industries. Peptides extracted from scales of various fish protect against ultraviolet B (UVB)-induced skin damage and photo-aging. However, the protective effects of collagen peptides derived from the scales of Branchiostegus japonicus against UVB exposure are unclear. This study investigated the effects of peptides larger than 1 kDa (high-molecular weight peptides [HMP]) and smaller than 1 kDa (low-molecular weight peptides [LMP]), derived from extracts of B. japonicus scales, against UVB-induced skin damage and photo-aging. These peptides scavenged 1,1-diphenyl-2-picrylhydrazyl radicals in a dose-dependent manner. In UVB-exposed HaCaT human keratinocytes, LMP inhibited 8-isoprostane generation, a marker of cellular lipid peroxidation. The peptides also suppressed the UVB-induced increase in tyrosinase activity and melanin content in B16F10 mouse melanoma cells. In addition, the LMP and HMP treatment suppressed UVB-induced elastase and matrix metalloproteinase-1 activities in the HaCaT cells. These results indicate that peptides derived from B. japonicus scales have antioxidant, antiphoto-aging, and skin-whitening effects.

• Environmental and Resource Economics Review
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• v.14 no.3
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• pp.699-728
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• 2005

This article is basically an extension of Barten(1993), Brown et al. (1995), Holt and Bishop's(2002) price formation system. A new dynamic price formation system is attempted considering full rationality of the consumers' side. The underlying idea of the new dynamic price formation system is that consumers are rational and farsighted and thus consider past and future consumptions in addition to current consumption to accept the prices traders called. In an empirical application, the U.S. commercial fish demand data are particularly interesting to this analysis in which the species are over fished, including many of the most valuable species. Especially, the grouper-snapper complex are under management jurisdiction of the National Marine Fisheries Council. In the empirical section, it shows how to adapt the model to estimate the marginal values to consumers of commercial fisheries. Since it is conceived of regulations as inducing movements along the marginal value curves, it is of growing importance to regional and national policy makers who are confronted with competing claims on diminishing fish stocks by commercial fisheries interests. It performs well and shows the plausible signs and magnitudes of price flexibilities and interaction among species. It further contributes to the general methodology of applied economics.

• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.75-83
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• 2018

This study is to observe species identification and early life history of Korean endemic species of Tanakia latimarginata and to use it as a basis for taxonomic studies. As a result of morphological identification, a dark band appeared at the margin of the anal fin, and the ovipositor color of the female was light orange. The shape of the egg was fusiform and sticky. The egg size (long${\times}$short diameter) averaged $4.41{\times}1.44mm$. The incubation time was 126 hours after the fertilization at an average water temperature of $21.0^{\circ}C$. Immediately after hatching, the larvae had egg yolk at an average total length of $5.91{\pm}0.18mm$ (n=5). At 18 days after hatching, the trunk fur was developed in the caudal fin with an average total length of $8.02{\pm}0.08mm$ (n=5). At 41 days after hatching, the larvae absorbed egg yolk at an average total length of $8.70{\pm}0.23mm$ (n=5). At 80 days after hatching, the average length of the fins was $12.6{\pm}0.28mm$ (n=5). The number of fin of the dorsal fin was iii.8, the anal fin iii.9~10, the caudal fin 19, lateral line scales 32~35 were similar to their brood stork.

• Journal of Aquaculture
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• v.22 no.1
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• pp.1-4
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• 2009

A 10-week feeding trial was conducted to investigate the effects of feeding rate on growth and body composition of adult flounder during the summer season. Three replicated groups of the fish (initial mean weight of $535{\pm}4.1\;g$) were hand-fed a extruded diet twice a day at the different feeding rates of satiation (100%), 90%, 80% and 70% of satiation for 10 weeks. Mean Water temperature was $19.2{\pm}2.8^{\circ}C$ during the feeding trial. Weight gain and condition factor increased significantly with increase in daily feeding rate (P<0.05), but there was no significant difference in weight gain of fish fed the diet between 100% and 90% of satiation. Survival and feed efficiency were not significantly different among all groups. Proximate composition of dorsal muscle was not significantly affected by feeding rate. Based on the results of this study, optimum feeding rate for growth and condition factor of adult flounder (535-928 g) seemed to be 90% of satiation.

• The Journal of Fisheries Business Administration
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• v.1 no.2
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• pp.1-22
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• 1970

Our fisheries protucts industry has developed rapidly during past 10 years ; production was about twice: fihing fleets increased twice in number and 3 times in tonnage ; export was 5 times. Govermment is trying to develop deep sea fisheries in order to surmount the depression of coast fisheries. At present more than 270 deep sea fishing boats are working with superior skill to other country at the South Pacific, the Atlantic, the Indian, and the North Pacific Ocean. Our deep sea fisheries is consisted of the tuna long line and the trawler. The tuna long line of them has 230 crafts in 1969 ana the deep sea trawler has 40 crafts, too. Comparing to 1962, the number of the deep sea fishing boats has been increased highly to 54 times, 7.71 times average per year increasing rate. The rate of the tuna long line to the trawler at the end of 1969 shows 85:15, More than half of them are 100~200 (equation omitted), if we classify them according to (equation omitted) or boat craft. 70% of them has less than 5 years ships age. The Korean Marine Industry Development Corporation has more than 1/3 fishing fleets, with 91 crafts, if We consider it according to corporation. Considering it according to the financial resources, dependence upon foreign loan is as high as 88%. Catches was 74, 450 M/T ($24, 663, 000)at the end of November in 1969 and it was increased to 113.5 times in catch amount and 118 times in value, comparing to those of 1962. Considering it according to the ocean, the order is arranged to the Pacific, the Atlantic, and the Indian Ocean. The average production amount of each craft is 250~400 S/T a year. The result of export took up 1/3 of total fisheries product export with $ 22, 398, 000 at the end of november in 1969. Employee cost of fishing coast is 8% higher than other fishing. The profit is highest in our fisheries. Most of the products except the trawler fishing are sofa at the fishing grounds to the processing company, and they lose much money. They buy most of bait from Japan, giving $8~10 for 1C/S(10kg). Fish price is $390~520 according to the kind of fish for S/T at the fishing grounds, and the rapid frozen fishes brought to Japan are about $ 800 for S/T. There is much difference. in price. Problems 1. Want of self capital. 2. To get the refrigeration boats enough. 3. International Fishing Regulation. 4. To get high price and to secure consuming grounds. 5. To get home-production of bait. 6. To exploit new fishing grounds. 7. To get larger boats. 8. To get mariner enough. When the problems mentioned above are solved, the Deep Sea Fisheries of oun courtry will be developed more largely.