• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.419-420
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• 2004

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.107-111
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• 2006

We described the scale characteristics of induced hybrids between female red seabream (Pagrus major Temminck et Schlegel) and male black seabream (Acanthopagrus schlegelii Bleeker), and of their parental species. The external scalar morphology of induced hybrids showed intermediate characters compared to those of the parental species. The mean number of primary apical grooves and lateral line scales was $10.5{\pm}2.6$ and $49.5{\pm}0.5$, respectively, in induced hybrids, which also showed intermediate meristic characters compared to those of the parental species (P<0.01). The meristic characters used in this study may be useful parameters for the identification of genotypes of these seabream species.

• Journal of fish pathology
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• v.16 no.2
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• pp.75-80
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• 2003

Red scabream, Pagrus major , is a valuable aquaculture species in Korea , but spontaneous eye abnormality occurred in cultured individuals . The incidence of eye abnormality was 4% in the group of cultured red scebream. The abnormality was characterized by unilateral and bilateral exophthalmos, opacity and lens pathology. Lense prolapse was found in two cases. Lenses in diseased fishes was considerably small in diameter and eyes were deformed as a whole. In the group of induced hybrid red scabream Pagrus major (♀) x black seabrearn Acanthopagrus schlegeli (♂), the incidence of eye abnormality wa~ the same 4%, but only opacity was registered. Opacity was also found in two of sixteen examined Wild-caught red seabrcam. Histopathological changes of lenses in cultured red seabreem included vecuolated cytoplasm of lens fibers, necrosis of fibers in central part of lens, folding and increase in thickness of lens capsule, and epithelial proliferation beneath the anterior lens capsule. In affected eyes no parasites or gas bubbles were found.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.769-773
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• 2001

In order to obtain the fundamental data on the underwater sound of fishes for marine ranching. The underwater sound of Red Seabream(Pagrus major) and Schlegel's black rockfish(Sebastes schlegeli) were measured, which character were summarized by FFT analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.2
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• pp.393-399
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• 2001

In order to obtain the fundamental data on the underwater sound of fishes for marine ranching. The underwater sound of Red Seabream(Pagrus major) and Schlegel's black rockfish(Sebastes schfegeli) were measured, which character were summarized by FET analysis.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1794-1799
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• 2008

This preliminary feeding trial was conducted to study the effects of different dietary selenium (Se) levels on growth performance and toxicity in juvenile black seabream, Acanthopagrus schlegeli (Bleeker). Fish averaging $7.0{\pm}0.1g$ ($mean{\pm}SD$) were fed one of the five semi-purified diets containing 0.21, 0.30, 0.52, 1.29 and 12.3 mg sodium selenite ($Na_2SeO_3$)/kg diet (Se 0.21, Se 0.30, Se 0.52, Se 1.29 or Se 12.3) for 15 weeks. After the feeding trial, weight gain (WG), feed efficiency (FE), specific growth rate (SGR) and protein efficiency ratio (PER) of fish fed Se 0.21, Se 0.30, Se 0.52 and Se 1.29 diets were not significantly different, however fish fed Se 12.3 diet showed significantly lower WG, FE, SGR and PER than those of fish fed the other diets (p<0.05). Fish fed Se 0.21, Se 0.30, Se 0.52, Se 1.29 and Se 12.3 diets showed no significant differences in hematocrit (PCV), hemoglobin (Hb) and red blood cells (RBC), however fish fed Se 12.3 diet showed lower values of PCV, Hb and RBC than those of fish fed the other diets. Histopathological lesions such as tubular necrosis and polycystic dilation of tubules in the kidney tissues were observed in fish fed Se 12.3 diet. Se was accumulated in a dose-dependent manner in the liver, kidney, muscle and gill tissues. Based on the results of this preliminary feeding trial, a dietary Se level of 0.21 mg $Na_2SeO_3/kg$ diet could be optimal for proper growth performances, and a dietary Se level of 12.3 mg $Na_2SeO_3/kg$ diet may ultimately be toxic to juvenile black seabream, Acanthopagrus schlegeli.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.819-826
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• 2013

The black seabream Acanthopagrus schlegelii is an important species for aquaculture in Korea. There are, however, no reports on the physiological responses to hypoxia in this species. The objective of this study was to evaluate the effects of acute hypoxia on the physiological stress responses (plasma cortisol as the primary response, and plasma glucose, hematocrit (Ht), hemoglobin (Hb), sodium, chloride, osmolality, AST, ALT and total protein as the secondary responses) of the fish. The experimental fish were exposed to 0.5 ppm dissolved oxygen (DO) in the seawater via two methods (progressive stepwise decline (Exp. I), and direct decline (Exp. II)). A highly significant increase was detected in plasma cortisol levels due to the hypoxia treatments, and fish in Exp. I had hormone levels that were significantly higher than the fish in Exp. II. For plasma glucose, there was no significant difference between the Exp. I fish and the control fish, whereas Exp. II fish showed significantly higher plasma glucose levels than Exp. I fish and control fish. Ht values increased in both hypoxia treatments; however, Hb concentrations increased only in Exp. I. Although plasma chloride levels were unaffected by acute hypoxia, plasma sodium and osmolality levels increased in Exp. I. Progressive hypoxia (Exp. I fish) increased plasma AST, ALT and total protein. These results suggest that the value and direction of changes to the investigated parameters can be used to determine the resistance of black seabream to acute hypoxia.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.828-836
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• 1996

The histological changes of gill, liver, spleen and muscle, and respiration and blood variables and liver glycogen content were examined in black seabream, Acanthopagrus schlegeli. Fish were exposed to a high level of total ammonia nitrogen (10.4 mg/l) and recovered from exposure $(0.4{\pm}0.2mg/l)$ in a closed recirculating seawater system. In the process of exposure, mortality was $9\%$, and hyperplasia, necrosis or inflammation appeared in all tissues except for muscle. Oxygen consumption was decreased by $49\%$, and red blood cell (RBC) number, hematocrit and hemoglobin concentration were significantly decreased, while plasma glucose contents, activities of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) increased. Liver glycogen content significantly increased from $6.6\%\;to\;10.4\%$. A large amount of hemosiderin was observed in the splenic tissue. During the recovery period, RBC number, hematocrit, hemoglobin concentration, GOT and GPT activities were returned to the normal status. Histological status of liver tissue was returned to the normal, but liver glycogen content was not recovered. During the recovery period, spleen melanin-macrophages temporarily increased, but subsequently decreased to the normal status.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.2
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• pp.119-128
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• 2002

This study investigates dorsal aspect target strength with fish size, tilt angle and frequency characteristics for the schlegel's black rockfish(Sebastes achlegeli) and the red seabream (Pagrus major). This study was carried out on free swimming fish in a cage in order to obtain acoustic data of the biomass estimation using the scientific echo sounder. The results obtained from this study are summarized as follows; 1 The coefficients of the schlegel's black rockfish and the red seabream using maximum TS with fish length were expressed -63.7dB and -62.6dB at a frequency of 38kHz, -64.4dB and -65.4dB at 120kHz, and -62.4dB and -65.0dB at 200kHz, respectively. 2. The coefficients of the schlegel\`s black rockfish and the red seabream using averaged TS with fish length were expressed -68.4dB and -67.9dB at a frequency of 38kHz, -73.4dB and -72.7dB at 120kHz, and -70.BdE and -73.4dB at 2001Hs, respectively. 3. The coefficients of the schlegel's black rockfish and the red seabream using maximum TS with body weight were expressed -52.0dB and -50.9dB at a frequency of 38kHz, -52.7dB and -53.7dB at 120kHz, and -50.7dB and -53.3dB at 200kHz, respectively. 4. The coefficients of the schlegel's black rockfish and the red seabream using averaged TS with body weight were expressed -56.7dB and -56.2dB at a frequency of 38kHz, -61.7dB and -61.0dB at 120kHz, and -59.ldE and -61.6dB at 200kHz, respectively. 5. Varying the tiIt angle of the two red seabream from -26$^{\circ}$to +25$^{\circ}$, the variation width of target strength expressed smaller at a frequency of 38kHz than at 120kHz and expressed about 3~6dB higher head up than head down at 120kHz.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.1
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• pp.48-53
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• 2008

Twelve black seabreams (Acanthopagrus schlegeli) were tagged with acoustic transmitters and their movement and behavior patterns were tracked using acoustic telemetry from 12 December 2006 to 15 August 2007. Seven of the 12 fish stayed within 500 m of the release point for over a month. In the spring tide, the number of detected signals and swimming depth of tagged fish changed at 12-hour intervals with the ebb tide. The number of detected signals of tagged fish decreased dramatically with the passage of time and had decreased by over 80% in May 2007, compared with January 2007.