• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.111-117
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• 2000

To clarify the ichthyotoxic mechanisms of a harmful dinoflagellate Cochlodinium polykrikoides, hematological responses of the flounder Paralichthys olivaceus and red sea bream Pagrus major exposed to this algal bloom were investigated. The mortality of red sea bream was considerably larger than that of flounder, and the threshold lethal density of C. polykrikoides to the test fish was approximately 3,000 cells/ml. Blood $PO_2$declined in proportion to the increasing density of algal cells. The blood $PO_2$ of moribund fish was about $40-60\% of control test fish. Particularly, the fishes began to be killed when the blood $PO_2$ fell below 30-40 mmHg. However, the blood pH dropped almost 1.0 unit just before fish kill. Hemoglobin and hematocrit levels of fish exposed to C. polykrikoides of 5,000 cells/ml for 24 h and of moribund fish did not show great difference. The concentrations of plasma $Na^+$, $K^+$ and $Cl^-$ were slightly elevated to different magnitudes except $Ca^{2+}$ and plasma osmolality was also increased in Cochlodinium-exposed fish. In the plasma cortisol level, these values of moribund flounder and red sea bream were 4- 5 times higher than those of control fish. These results suggest that the drop of blood $PO_2$ was may be one of the principal causes of fish kill by C. polykrikoides, and the changes of other hematological parameters were secondary responses elicited by the decrease in blood $PO_2$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.686-693
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• 2012

The seaweed community and stomach contents of the dominant herbivorous sea urchins Anthocidaris crassispina and Hemicentrotus pulcherrimus were examined from November 2008 to October 2009, in coastal areas of Tongyeong, Korea. Thirty-five seaweeds including two green, nine brown, and 24 red algae, were found over the study period. Seventeen seaweeds (two green, two brown, and 13 red) and two invertebrates were found in the stomachs of A. crassispina. In H. pulcherrimus, stomach contents were two green, one brown, 11 red seaweeds, and two invertebrates. The shell diameter of A. crassispina and H. pulcherrimus ranged from 22.3 to 62.3 mm and 15.3 to 40.1 mm, respectively. Total body weights ranged from 48.5 to 86.7 g for A. crassispina and from 7.7 to 25.9 g for H. pulcherrimus. The total weight of stomach contents were 5.1 to 25.8 g in A. crassispina and 1.7 to 11.8 g in H. pulcherrimus. The range of gonad weight was 3.6 to 17.0 g in A. crassispina and 0.8 to 4.0 g in H. pulcherrimus. The gonad index (GI) for A. crassispina peaked in July and reached a minimum in December, whereas the GI for H. pulcherrimus was highest in February, and lowest in May.

• Korean Journal of Veterinary Research
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• v.47 no.2
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• pp.241-245
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• 2007

Parallux (IDEXX Laboratories, USA), a solid-phase fluorescence immunoassay (SPFIA) developed for antibiotics residue detection in milk, was applied for analysis of antibiotics in muscle tissue of olive flounder (Paralichthys olivaceus), rockfish (Sebastes schlegeli), and red sea bream (Pagrus major). Fishes were dipped in streptomycin 20 g/ton water, the recommended therapeutic dose, for 3 consecutive days. Muscle was sampled after 1st, 2nd, 3rd, 4th and 5th day drug treatment. The concentration of streptomycin in muscle, determined by SPFIA, was compared with that of internal standard (200 ppb as streptomycin). The absorbance ratio of sample to internal standard (S/C) was employed as an index to determine the muscle residues in fishes. The standard solutions were added to muscle samples to give final concentrations in muscle of 0.2 and 0.5 mg/ml to investigate the recovery rate. The recovery rates of all spiked samples were > 84% of the spiked value. Streptomycin was detected in muscles of fishes treated after the 1st day of withdrawal period. The present study showed that the SPFIA can be easily adopted in predicting muscle tissue residues for streptomycin in farmed fishes.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.1
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• pp.35-40
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• 1985

The author carried out experiments to find out the response of rock bream, Oplegnathus fasciatus (TEMMINCK et SCHLEGEL) and sea bass, Epinephelus septemfasciatus (THUNBERG) to the color nettings. The experimental water tank(180L$\times$50W$\times$55Hcm) was set up n a dark room and water level was maintained 50cm high from the bottom. The tank was devided three longitudinal sections marking 60 cm interval. The illumination systems, consisted of 20 watt fluorescent lamps and filter, were suspended adove the tank. Two different color nettings selected from five colors (red, yellow, green, blue, black) were placed in each end section of the tank. Ten fish were used in each experiment and the fish were acclimatized in the dark for 60 minutes before experiment. After the light on, the number of fish in each section of the tank was counted in every 30 seconds interval for 30 minutes. The results obtained are as follows: 1. The rock bream selected the color nettings in the order of yellow, black, blue, green and red. 2. The sea bass selected the color nettings in the order of green, black, red, blue and yellow.

• Journal of fish pathology
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• v.21 no.1
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• pp.13-20
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• 2008

This study evaluates the pathogenicity in striped beakperch, Oplegnathus fasciatus infected with red sea bream iridovirus (RSIV) at different water temperature (17°C, 20°C, 25°C and 27°C). When the fish group was infected with RSIV at 17°C and 20°C, cumulative mortality did not show any significant difference with control group. In contrast, the case at 25°C and 27°C, cumulative mortality reached more than 80%. However, RSIV was detected from all of the fish in each temperature. To confirm a relationship between temperature change and heat shock protein (HSP), partial HSP70 cDNA was isolated from striped beakperch.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.62-72
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• 2018

An active ingredient with hyaluronidase (HAse) inhibitory effect is one of the anti-aging approaches in cosmeceuticals. Here, red sea cucumbers (RSCs), Stichopus japonicus, from Jeju Island were evaluated to examine their HAse inhibitory and antioxidant activity effect. In this study, RSCs were extracted by six enzymatic hydrolysis (Alcalase; Al, Trypsin; Try, Neutrase; Neu, Pepsin; Pep, Alpha-chymotrypsin; Chy and Protamex; Pro). Alcalase hydrolysate (AlH) showed the highest antioxidant capacities for both of oxygen radical absorbance capacity (ORAC) and trolox equivalent antioxidant capacity (TEAC) methods, compared to those of other hydrolysates, at $66.59{\pm}0.78{\mu}M\;TE/mg$ and $135.78{\pm}3.24{\mu}M\;TE/mg$, respectively. Furthermore, AlH performed the highest capacity of HAse inhibitory with $IC_{50}$ value of 3.21 mg/ml. Thus, RSCs hydrolyzed by Al were chosen to determine the cellular antioxidant activity and hyaluronic acid (HA) production effect on Human immortalized keratinocyte cell line (HaCaT). The results showed that AlH improved the cell viabilities and intracellular reactive oxygen species (ROS) induced by 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH) were significantly decreased. In addition, AlH increased HA amount by regulating HYAL2 and HAS2 expressions in the HaCaT cells. Taken together, AlH of RSCs collected from Jeju Island showed HAse inhibitory and antioxidant activities against skin-aging which shows its potentials can be an optional natural bioactive ingredient for novel cosmeceuticals.

• Journal of fish pathology
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• v.34 no.1
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• pp.1-7
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• 2021

Red sea bream iridovirus (RSIV), belonging to the genus Megalocytivirus, is the predominant cause of mortality in marine fishes in Korea, including rock bream (Oplegnathus fasciatus). Rockfish (Sebastes schlegelii) are the host fish for RSIV, exhibiting no clinical signs or mortality. Cohabitation challenges, which mimicked natural transmission conditions, were performed to evaluate viral transmission between rock bream and rockfish, and to determine the pathogenicity and viral loads. In cohabitation challenge, artificially RSIV-infected rock bream were the viral donor, and healthy rockfish were the recipient. The results showed that although the donor rock bream had 95-100 % cumulative mortality (>10⁸ viral genome copies/mg of spleen 7-14 days after viral infection), the recipient rockfish did not die, even when the viral genome copies in the spleen were >10⁵ copies/mg. These results indicated asymptomatic infections. Notably, in a reverse-cohabitation challenge (artificially RSIV-infected rockfish as the viral donor and healthy rock bream as the recipient), RSIV horizontally infected from subclinical rockfish to rock bream (10⁷ viral genome copies/mg of spleen 21 days after cohabitation) with 10-20% cumulative mortality. These results suggest that an asymptomatic, infected rockfish can naturally transmit the RSIV without being sacrificed.

• Journal of fish pathology
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• v.37 no.1
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• pp.25-36
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• 2024

In this study, we analyzed the phylogenetic classification, epitope prediction, and pathogenicity of red sea bream iridovirus (RSIV) isolated from rock bream between 2019 and 2023. Phylogenetics based on genes encoding MCP and ATPase indicated that all five RSIV isolates belonged to RSIV subtype II. The deduced amino acid sequence of the MCP for the amplicons (1362 bp) obtained from RSIV isolates had a length of 453 amino acids. Among these, the amino acid sequences of the RSIV-19, 21, 22, and 23 isolates showed 100% identity, while the RSIV-20 isolate showed 99.78% identity with one residue difference at position 306. As a result of antigenicity analysis based on amino acid sequence, the antigenicity score of the RSIV-20 isolate was 0.6386 and the other RSIV isolates were 0.6365. Additionally, the prediction of their antigenic determinants resulted in a total of 17 identical antigenic plots. When each RSIV was inoculated into rock bream, no significant differences were observed with 100% cumulative mortality in all groups. This study provides data on the potential for genetic variation of RSIV isolated in the same marine area over the past five years, and the antigenicity and pathogenicity results of each isolate are expected to be useful information for selecting future vaccine strains.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.373-374
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• 2003

There were many studies on the effects of red tide dinoflagellates on shellfish populations (Nielsen and Stromgren, 1991; Lesser and Shumway, 1993; Luckenbach et al., 1993; Matsuyama et al., 1997; Li et al., 2001). However, these studies mainly focused on the toxic effects of dinoflagellates oui adults or juveniles. Interactions between dinoflagellates and bivalve larvae have not been understood comprehensively yet. (omitted)

• Journal of Ocean Engineering and Technology
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• v.24 no.2
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• pp.53-56
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• 2010

Oil spills and red tide can be very damaging to the environment and fishery farming. These catastrophic accidents must be detected as quickly as possible. In this paper, we report the results of applying the wavelet transform to SAR or marine radar images for the detection of the boundaries of an oil spill or red tide. The application of the wavelet transform to these phenomena looks quite promising in detecting the boundaries of oil spills and red tide areas.