• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.862-867
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• 2013

Since the industrial revolution, seawater has increased in temperature and acidity due to the increase in anthropogenic carbon dioxide in the atmosphere. To understand the effect of elevated $CO_2$ on the early life stages of fish, we reared fertilized eggs of black sea bream Acanthopagrus schlegelii under three $CO_2$ concentrations (400, 850 and 1550 ppm) for 3 weeks. The standard length and wet weight of black sea bream larvae declined with enhanced $CO_2$ concentration in the rearing water (P<0.05). However, chemical analysis using ICP-OES on internal tissues of black sea bream larvae indicated that the whole-body calcium concentration increased with $CO_2$ concentration in the rearing water. These conflicting results suggest that future experiments should examine the acid-base balance to investigate the formation of bone and otolith during larval growth.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.3
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• pp.387-394
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• 2012

Fertilization rates were over 90% when sperm from black porgy Acanthopagrus schlegelii acclimated and raised in freshwater and black porgy raised in seawater were fertilized with eggs from female black porgy raised in seawater, although cryopreserved sperm were significantly lower in fertilization rates than non-cryopreserved sperm. From the observations of embryos development at different salinities (0, 10, 20 and 32 psu) within 3 hours upon fertilization (16 cell stage), all were dead at 0 psu. However, the development process and speed at 10 and 20 psu were the same as at 32 psu. But, many developing embryos were egg envelope injury at low-salinities of 10 and 20 psu unlike at 32 psu. This is attributable to osmotic shock. Hatching rate of embryos at 32 psu was 60% or so, whereas low as 5% or less were successfully hatched at 10 and 20 psu, implying that osmotic shock could be responsible for the failure of embryo development.

• Development and Reproduction
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• v.15 no.2
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• pp.151-158
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• 2011

The comparison of the chemical properties of semen of black porgy Acanthopagrus schlegelii long-term acclimated reared in freshwater (BFW) and seawater (BSW) with sperm activity of salinity and ion composition. The chemical properties of seminal plasma on BFW of the factors that most there was not significant difference in the BSW. However, osmolality in seminal plasma of BFW and BSW was $307.0{\pm}4.6$ and $337.3{\pm}10.1$ mOsm/kg, respectively, where BFW showed significant lower concentration in contrast to BSW. Salinity effect on sperm motility of BFW and BSW in 0 psu solution, no sperm motility was observed, whereas in 10 psu solution, both BFW and BSW sperms showed low motility and short time post sperm activation. However, diluted in 20 and 32 psu solutions, highest motility and long time post sperm activation were observed in BFW and BSW sperm. SAI of BFW and BSW varied in depend on the osmolality regardless of ion kind and it showed the highest value in the similar osmolality of artificial seawater (956 mOsm/kg). Accordingly, even in sperm released from BFW, factors initiating sperm motility are determined by osmolality.

• Fisheries and Aquatic Sciences
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• v.20 no.6
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• pp.11.1-11.8
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• 2017

Juvenile black sea bream, Acanthopagrus schlegelii, were exposed to waterborne zinc (Zn) at concentrations of 0, 200, and $400{\mu}g/L$, at temperatures of 18 or $26^{\circ}C$ for 4 weeks. Superoxide dismutase (SOD) activities in the liver and gill of A. schlegelii significantly increased following exposure to waterborne Zn. Significant reduction in glutathione S-transferase (GST) activity in the liver and gill was observed following exposure to waterborne Zn. Glutathione (GSH) concentrations in the liver and gill also significantly decreased following exposure to waterborne Zn. Phagocytosis and lysozyme in the plasma and kidney were significantly increased following exposure to waterborne Zn. High water temperature increased alterations in the antioxidant and immune responses. The results of the present study suggest that waterborne Zn induced significant alterations in oxidative stress, increased immune responses and high temperature that trigger Zn toxicity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.923-929
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• 2013

Black seabream juveniles Acanthopagrus schlegelii held at $20^{\circ}C$ were exposed to formalin at concentrations of 50 to 400 ppm, and tolerance values were determined by calculating median lethal concentration values (LC50) through probit analysis. The 12-, 24, 48, 72- and 96-h LC50 values for formalin were 297, 233, 171, 162 and 157 ppm, respectively. The histological effects of formalin on gill and liver tissues in this fish were determined. No histological effects were observed in the control group. The intensity of cell damage increased with the concentration of, and duration of exposure to, formalin. Hyperplasia, separation and epithelial necrosis, epithelial lifting, lamellar synechiae and collapsed lamellae were observed in gill tissues exposed to formalin. Hepatic lesions in liver tissues of fishes exposed to formalin were characterized by cloudy swelling of hepatocytes, necrosis, cytoplasmic vacuolization, deposition of pigments, spongiosis hepatis, nuclear hypertrophy, dilation of sinusoids and bile stagnation. The LC50 values and histological results obtained in this study will aid in designing treatment regimens to minimize toxic side effects and increase efficacy.

• 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 Ichthyology
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• v.8 no.1
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• pp.9-13
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• 1996

To study on the growth of young stage Acanthopagrus schlegelii, samples were collected from the shallow waters off Kunsan, Korea from July to December, 1995. The planctonic larvae of Acanthopagrus schlegelii were collected in early June. The young fish of 12.7~26.6 mm in total length began to appear in the shallow water in late June. They grew up 19.9~51.4 mm in middle July, 24.8~75.0 mm in late July, 63.3~79.6mm in middle August. A. schlegelii disappear from the shallow water after middle August, and began to be collected in the outer bay off Kokunsan Isls. by long back net. This species that had spawned from Kunsan coast in late June to middle August grew up to 100mm in total length in December of that year.

• 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.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.4
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• pp.314-322
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• 2021

Paired box protein, PAX7, is a key molecule for the specification, maintenance and skeletal muscle regeneration of muscle satellite cells. In this study, we identified and characterized the cDNA and amino acid sequences of PAX7 from black sea bream (Acanthopagrus schlegelii) via molecular cloning and sequence analysis. A. schlegelii PAX7 cDNA was comprised of 1,524 bp encoding 507 amino acids and multiple sequence alignment analysis of the translated amino acids showed that it contained three domains including paired DNA-binding domain, homeobox domain and OAR domain which were well conserved across various animal species investigated. Pairwise Sequence Alignment indicated that A. schlegelii PAX7 had the same amino acid sequences with that of yellowfin seabream (A. latus) and 99.8% identity and similarity with that of gilt-head bream (Sparus aurata). Molecular phylogenetic analysis confirmed that A. schlegelii PAX7 formed a monophyletic group with those of teleost and most closely related with those of the fish that belong to Sparidae family including A. latus and S. aurata. In the investigation of its tissue specific mRNA expression, the expression was specifically identified in skeletal muscle tissue and a weak expression was also shown in gonad tissue. The cultured cells derived from skeletal muscle tissues expressed PAX7 mRNA at early passage but the expression was not observed after several times of subculture.

• Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.44-47
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• 2006

Morphometric characteristics of female red sea bream, Pagrus major (Temminck et Schlegel) and male black sea bream, Acanthopagrus schlegelii (Bleeker) hybrids is described. From the result of our study, the morphometric characters of hybrid may be 7 paternal-like, 2 maternal-like or even out of the range of parental species. The pigmentation of the hybrid is intermediate in some respects and resembles that of the parental species in others. This study of characterization in morphometric traits of the hybrids, red sea bream and black sea bream may be useful for distinguish of each genotype in commercial sea bream aquaculture.