• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.201-205
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• 2010

One specimen of a natural hybrid of an Oplegnathus (Oplegnathus fasciatus $\times$ Oplegnathus punctatus) was found in Tongyeong, Korea in August 2008. We, herein, describe its morphological and genetic characteristics and compare them with those of O. fasciatus and O. punctatus. In morphology, the hybrid showed many distinctive black rounded blotches on body sides and four faint vertical bars, being in those features similar to O. punctatus. Although the counts and measurements of the hybrid mostly overlapped between O. fasciatus and O. punctatus, the Oplegnathus hybrid resembled O. punctatus in the ratio of pelvic-fin length in standard length: Oplegnathus hybrid (26.7%) was closer to O. punctatus (26.4%) than to O. fasciatus (17.2~23.6%). In genetics, as a result of analysis of 510 base pair sequences of mitochondrial DNA 16S rRNA, the hybrid was closer to O. fasciatus (d=0.000~0.010) than to O. punctatus (d=0.020). Our results suggest that the natural hybridization represented by the subject specimen occurred between an O. fasciatus female and an O. punctatus male.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.5
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• pp.725-732
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• 2020

The sudden drop of water temperature in winter is very threatening factor that affects the productivity of farmed fish and the management in aquafarm. In this study, we investigated the effect of low temperature on the survival, oxygen consumption and stress responses of parrotfish Oplegnathus fasciatus due to acute drop of water temperature. The survival rate of parrotfish Oplegnathus fasciatus was 5% at 6℃, 95% at 8℃ and 100% at 10℃ on the 4^th day of exposure in each experimental temperature. Low-lethal temperature for 4days of parrotfish Oplegnathus fasciatus (4 day-LT₅₀) was 6.99℃ (confidence limit, 6.55-7.42℃). Oxygen consumption rate was significantly decreased with decreasing water temperature. Temperature coefficient (Q₁₀) was found to be 4.0 between 10℃ and 8℃ and 0.39 between 8℃ and 6℃. As a result of investigating the stress response according to the drop in water temperature, the concentration of SOD (Superoxide dismutase), cortisol, glucose, total Ig, AST (Aspartate) and ALT (Alanine aminotransferase) increased with decreasing of water temperature. This study would be useful for the management of temperature about cultured fish.

• Journal of fish pathology
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• v.29 no.1
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• pp.7-12
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• 2016

In a previous study on the parasites of cultured rock bream (Oplegnathus fasciatus), we reported the discovery of a new species, Ceratomyxa oplegnathus, obtained from the gallbladder. In the present study, we found another Ceratomyxa species, C. sparusaurati, also from the gallbladder of rock bream. The morphological and ultrastructural characteristics of C. sparusaurati were investigated using light and transmission electron microscopy (TEM).

• Journal of fish pathology
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• v.19 no.2
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• pp.109-117
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• 2006

A new myxosporean species Ceratomyxa oplegnathus n. sp. was found from the gallbladder of cultured rock bream, Oplegnathus fasciatus. Mature spores were 44.14 ± 2.41 (39.04-48.41) ㎛ in length, 8.52 ± 0.36 (7.9-9.26) ㎛ in width in sutural view. Spores contained two spherical polar capsules measuring 3.04 ± 0.2 (2.71-3.37) ㎛ in diameter and a binucleated sporoplasm. Each polar capsule had a 5-6 coiled polar filament, and was situated near the sutural line. In ultrastructural observation, asynchronous divisions of generative cells without pansporoblast formation gave arise to 2 spores within a trophozoite. Sporoplasmic cell in the sporoblast was binucleated, and capsulogenic cells had large amounts of rough endoplasmic reticulum, external tubules, and capsular primordia.

• Korean Journal of Ichthyology
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• v.25 no.1
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• pp.25-32
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• 2013

We studied the age and growth of striped beakperch (Oplegnathus fasciatus) in the Jeju marine ranching area using a total of 423 otoliths from August 2009 to August 2010. The surface reading method, which was etched with 5% HCl, was the best method to read ages of this fish. The monthly mean fork length ranged from 20.9 cm to 27.7 cm in the Jeju marine ranching area during from August 2009 to August 2010. The annual ring was formed in July to September once a year. Fish were principally composed of 3 to 5 years old and the oldest was 12 years old. The von Bertalanffy growth parameters of this species, which were estimated from a non-linear regression, were $L_{\infty}$=48.20 cm, $t_0$=-1.031yr, and K=0.123/yr.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.376-382
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• 2014

This study determined the level of fermented soybean meal (FSM) that could be substituted for fish meal in the diet for parrot fish Oplegnathus fasciatus. Fish meal (FM) was used the sole protein source in the control diet. FSM was substituted for 20, 40, 60, 80, and 100% of the fish meal in the experimental diets. The FSM resulted in increased crude protein, crude fat, and crude ash, but decreased crude fiber. The methionine and tryptophan contents in the FSM increased, while lysine and threonine decreased. The 18:2n-6 fatty acid content decreased from 55.30% to 28.67%. Fermentation increased 20:5n-3 (EPA) and 22:6n-3 (DHA) by 2.03% and 15.54%, respectively, although the differences were not significant. Based on growth performance, we concluded that FSM could replace up to 60% of FM for the maximum growth of juvenile parrot fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.197-201
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• 2004

Juveniles of parrot fish (Oplegnathus fasciatus) were graded and divided into three groups (mean initial size): Small group $(32.9\pm3.2\;g),$ Large group $(130.1\pm12.3\;g)$ and Ungraded group $(74.8\pm29.8\;g).$ Growth and sex ratio were monitored over 3 years. It was concluded that no production advantage was gained by weight grading. There were no differences when the pooled data from the two graded groups were compared with the ungraded group, although mean weight and survival of the large group were continuously higher than those of other groups until the end of rearing period. The highest percentage of males was found in the large group. These results show that males start growing faster than females long before the size grading.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.840-846
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• 2014

This study investigated growth and hematological changes in parrotfish Oplegnathus fasciatus (~200 g/fish) reared under different total ammonia nitrogen (TAN) concentrations (0, 4, or 8 mg/L) for 6 weeks. Survival rates of parrotfish in all experimental groups did not significantly differ, as they were all ~100%. Although specific growth rate (SGR), weight gain, and daily feed intake in the high TAN concentration group (TAN8) were significantly lower than in the other two groups, there was no significant difference between the TAN4 group and the control group, (TAN0), indicating that parrotfish have a strong resistance to ammonia toxicity. As for temporal changes of the major blood components, cortisol increased as a result of stress caused by the high ammonia concentration in the TAN8 group. For this reason, the concentrations of energy sources such as glucose and total cholesterol were reduced. However, there was little difference among all experimental groups in concentrations of liver function glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), and nutrient factors, such as total protein and albumin.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.171-176
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• 2013

The aim of this study was to investigate the in vivo toxicity of di-2-ethylhexyl phthalate (DEHP), on the immune system of the rock bream, Oplegnathus fasciatus. Fish were injected twice intraperitoneally with DEHP (200, 400, and 800 mg/kg BW), and the cellularity and functional activity of phagocytes in the spleen and head kidney were measured. The number of head kidney leukocyte cells was significantly greater in fish treated with 800-mg DEHP/kg BW. Nonspecific immunity, as determined by the phagocytic index, was significantly decreased at 800-mg DEHP/kg BW in the head kidney. A significant reduction in phagocytic capacity was observed in the head kidney at ${\geq}$400-mg DEHP/kg BW. Furthermore, significantly increased levels of serum glutamic oxaloacetate transaminase and glutamic pyruvate transaminase indicated a marked hepatic dysfunction in immunosuppressed fish. Total serum protein was significantly reduced at ${\geq}$400-mg DEHP/kg BW; however, there were no significant changes in lysozyme activity. These results demonstrate that immune responses in the rock bream, Oplegnathus fasciatus can predict immunotoxicity at doses ${\geq}$400-mg DEHP/kg BW.

• Applied Microscopy
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• v.34 no.2
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• pp.139-143
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• 2004

The ultrastructure of the gills of Oplegnathus fasciatus was examined by means of light and transmission electron microscopes. The gills have primary and secondary filaments (lamellae). The following cells are identified and described : epithelial cell, pillar cell, chloride cell and mucose cell. The simple epithelial layer consists of squamous epithelium containing a large nucleus and the surface is covered with some of microridges. The lamella pillar structures are characterized by axial microtubules and lateral membrane interdigitations. Chloride cells contain a lot of mitochondria and specifically developed tubular systems. The rough endoplasimic reticulum and golgi complex, and some of mucous granules were observed in immature mucous cells. The mature mucous cells were AB-PAS positive, globular in shape, and had mucous granules of similar size with various electron densities.