• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1996.06a
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• pp.223-225
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• 1996

• The Journal of Fisheries Business Administration
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• v.52 no.3
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• pp.27-38
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• 2021

This study is aimed to figure out the productivity and variability of cage-aquaculture changes. According to the analysis, the productivity of major fish species has been increasing, except mullet. Although the regional productivity has decreased in the last two years, it has been on the rise considering as a whole. Gyeongsangnam-do showed the highest level of productivity by region. Productivity by species was also higher than other regions in the cases of rock fish, mullet and sea bream followed by productivity of Chungcheongnam-do. The production of marine cage-culture in Jeollanam-do is the second largest in Korea in value/weight while its productivity is lower than that of Chungcheongnam-do. When it comes to comparison by region, Gyeongsangnam-do shows the lowest productivity variation. And Jeollanam-do shows the second-lowest variation in productivity that is only about half of that of Chungcheongnam-do province. Thus, it is found that Jeollanam-do region has an advantage in management stability while its productivity is low. On the other hand, productivity by species was also analyzed. Gyeongsangnam-do has the highest productivity by species for rock fish, mullet and sea bream whereas rock bream productivity is the highest in Jeollanam-do. Therefore, it probably needs to reflect these results when choosing regional-focused incubation fish species.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.37-37
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• 2003

Intraspecific hybrids have been proven to be a useful tool for increase growth rate in some freshwater fish species. However the effects of intraspecific hybrids in seawater fish species is little known. To assess whether intraspecific hybrids in red sea bream was associated with growth enhancement, growth performances of offspring from two inbred lines, selected Korean line (KORDI-F4) and cultured Japanese line (IPN) and two intraspecific hybrids lines (KORDI-F4♀×JPN♂ and JPN♀×KORDI-F4♂) of red sea bream were compared. There's no significant difference in body weight between offspring groups during seed production period (until 4 months old). At seven months old (after three months rearing trials on sea cages communally), the offspring from KORDI-F4 (41.0±11.1g) and JPN♀×KORDI-F4♂ (39.3±8.1g) showed significantly better performance in body weight than that of the offspring from KORDI-F4♀×JPN♂ (37.0±8.1g) and IPN (35.7±9.7g). At 15 months old, the offspring from JPN♀×KORDI-F4♂ showed best growth performances in body weight, weight gain, specific growth rate among four offspring groups. As the results, the intraspecific hybrids between cultured Japanese line and selected Korean line showed superior growth performances than their paternal and maternal inbred lines.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.64-70
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• 2015

We investigated the branchial osmoregulatory response of black sea bream Acanthopagrus schlegelii to short-term (3-48 h) exposure to a hyposaline environment (5 psu). Gill $Na^+/K^+$-ATPase (NKA) activity was decreased after 3 h in fish transferred to 5 psu compared to salt water-acclimated (control) fish, but the level of activity returned to that observed in the control fish at 6 h after transfer. NKA activity increased significantly at 24 h after transfer, but it returned to the level observed in the control fish at 48 h after transfer. Immunohistochemical staining revealed that gill NKA was localized to chloride cells. The number of chloride cells tended to change in parallel with NKA activity. Substantial decreases in plasma $Na^+$, $Cl^-$, and osmolality were observed after 12 h of exposure to 5 psu; however, these parameters began to recover to the values detected in the controls at 24 h after transfer. In conclusion, our results suggest that black sea bream are able to adjust their osmoregulatory mechanisms to shift from hypo- to hyperosmoregulation within 6 h of exposure to a hypoosmotic environment.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.85-85
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• 2005

• Journal of fish pathology
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• v.26 no.2
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• pp.99-110
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• 2013

Hatchery-reared seeds provides a key source of animal protein for human consumption and restocking for fishery management. For stock enhancement program, we have inspected the hatchery-reared seeds of 33 species in 2009, 44 species in 2010, 43 species in 2011 and 46 species in 2012 for legally designated diseases. Results showed that abalone was the most abundant in the marine species group and then sea cucumber, olive flounder, rockfish and swimming crab were followed. Crucian carp was the most abundant and then mandarin fish, Korean bullhead, melanian snail and Chinese mitten crab were followed in the freshwater species group. The number of inspection for black sea bream, rock bream, scorpionfish, black scraper, and eel has continuously decreased for four years. The inspection for flathead mullet has been carried out only in 2009. The total number of inspection cases for eight pathogens in this study were 8,476 and disqualification cases were 56 (0.67%) by detection of aquatic animals pathogens such as koi herpesvirus, white spot syndrome virus, red sea bream iridovirus or viral haemorrhagic septicemia virus.

• Journal of fish pathology
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• v.23 no.1
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• pp.85-98
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• 2010

Ministry of Agriculture, Fisheries and Food (MAFF) and National Fisheries Research and Development Institute (NFRDI) have inspected the hatchery-reared seeds of 22 marine species and 11 freshwater species for aquatic animal diseases in stock enhancement program in 2009. Results showed that total 12 local selfgovernments have been restocking the sea with cultured juveniles. Gyeongsangnam-do, Jeollanam-do, Jejudo and Chungcheongnam-do have a preference for marine species seeds to freshwater species. On the contrary, freshwater species were released mostly in Gyeonggi-do, Jeollabuk-do and Chungcheongbuk-do. In the marine species group, abalone was the most abundant as 24.5%, and then sea cucumber (15.2%), olive flounder (11.5%), swimming crab (5.6%), black sea bream and rockfish (6.8%), rock bream (5.1%), black rockfish (4.6%) and scorpionfish (4.5%) were followed. Crucian carp was the most abundant as 19.4%, and then eel (17.0%), Korean bullhead (12.3%), melanian snail (12.0%), catfish (8.4%) were followed in the freshwater species group. The total number of inspection cases in this study were 1,080 and disqualification cases were 19 by detection of aquatic animals pathogens such as red sea bream iridovirus (RSIV), koi herpesvirus (KHV) or white spot syndrome virus (WSSV).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.400-404
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• 2004

Growth performances of the selected and the non-selected red sea bream (Pagrus major) lines were evaluated up to marketable size. The offspring were mass-produced either from the selected line (the fourth generation of broods from mass selection) or the non-selected line (the second generation of wild broods). Early (59 to 103 days old, trial I) and late growth performances (4 to 24 months old, trial II) were evaluated based on communal rearing in land-based tanks and sea cages, respectively. In trial I, the selected line exhibited significantly higher values in both weight gain (WG) and specific growth rate (SGR) when compared to those observed in the non-selected line (P<0.05). In trial II comprising of three growth phases (4-9, 9-16 and 16-24 months old), selected line showed only slightly improved in WG and SGR at the beginning two growth phases (4-9 and 9-16 months old) (P>0.05), however, displayed significantly higher values at the last growth phase (16-24 months old) (P<0.05). Overall WG and SGR throughout the experiment (4-24 months) were also significantly higher in the selected line than the non-selected line (P<0.05). Consequently, mean body weight of the selected line at 24 months old was 1.4-fold (40.8{\%}\;increased) as compared to that of the non-selected line. This present result indicates that mass selection of this species against the growth traits might be quite effective, and the present advance has important Implication in the productivity enhancement of red sea bream aquaculture.

• Journal of fish pathology
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• v.19 no.2
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• pp.155-164
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• 2006

Tissue distribution and residue depletion of oxytetracycline (OTC) and tetracycline (TC) following dipping administration were evaluated in olive flounder (Paralichthys olivaceus), rockfish (Sebastes schlegeli), and red sea bream (Pagrus major) under field conditions. Fishes were held in floating cages placed in sea water and fed a commercial diet for 15 days to acclimate to a new surrounding. Fishes were dipped in OTC 50 g/ton water for 30min and TC 18 g/ton water for 5 hours. Blood and muscle were sampled from fishes on 0th, 1th, 2th, 3th, and 5th day after administration. After solid-phase extraction, OTC and TC analyses were carried out by HPLC. The recovery rate of OTC in serum and muscle samples was 71-77% and 78-84%, respectively. Also, the recovery rate of TC in serum and muscle samples was 70-79% and 73-78%, respectively. The results of recovery rate were similar to previous studies reported. At the termination of dipping administration of OTC and TC, residue concentration in muscle samples of rockfish was significantly higher than those of olive flounder and red sea bream. At day 5, residue concentrations of all samples were believed to decrease to lower than 0.05 mg/kg, the detection limit. The present study showed that residue concentrations of OTC and TC decreased to below 0.05 mg/kg after treatment 5th day, faster than the established withdrawal period. The tissue reside depletion time of dipping administration of OTC and TC seems to be shorter than those of oral or parenteral administration.

• Journal of fish pathology
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• v.21 no.1
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• pp.35-43
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• 2008

Pathological symptoms and hematological parameters of red sea bream, Pagrus major and water temperature in the culture ground was investigated to clarlify the cause of winter moratility. Dead fish showed green liver and accumulation of ascites in the cavity. A few Bivagina tai were also found on the gill but either bacteria or virus were not. When hematological parameters from fish taken before/after the winter mortality were compared, blood glucose, serum AST and ALT, and total cholesterol, trigyceride and total protein were significantly decreased in the fish after the winter mortality. These results may explain that the nutritional level of fish was decreased because fish could not fed during winter season. According to the CORI monitoring system operating by KODC, NFRDI a long term water temperature from Dec. 25, 2005 to Feb. 24, 2006 (60 days) were exposed the low water temperature environments to the red sea bream. First of all, mass mortality began at Sarayngdo where low temperature below 8℃ continued for 42 days. The winter mortality did not occured in the depths of 9 m to 19.2 m where difference of water temperature in the surface and bottom was only within 0.1℃. But in the depth of 7.5 m to 11 m winter mortality occured where water temperature in the surface and bottom showed much variation ranged from 0.2℃ to 1.4℃. From these results, great difference of water temperature in the surface and bottom of the culturing area might results in winter mortality of red sea bream.