• 한국발생생물학회지:발생과생식
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• 제20권2호
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• pp.51-63
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• 2016

The landmark-based morphometric and meristic analysis of the kelp grouper (Epinephelus bruneus), red spotted grouper (E. akaara) and seven-banded grouper (E. septemfasciatus) were performed to compare the differentiation of overall body shape and structure. The measurements of the morphometric dimensions were observed in 25 parts (truss dimension: 16 parts; head part dimension: 9 parts) of 38 morphometric dimensions and also meristic differences observed in 3 parts (dorsal fin, anal fin and caudal fin) of 6 meristic counts (P < 0.05). Observed morphometric characteristics primarily involved in truss and head part dimension, kelp grouper have larger values in caudal part of truss dimension, kelp grouper, red spotted grouper and seven-banded grouper have similar values in pectoral part of truss dimension, in addition to, results of head part dimension showed that red spotted grouper have smaller values in overall dimensions (P < 0.05). As meristic characteristics, kelp grouper have more number of anal fin rays than other fish, red spotted grouper have more number of dorsal soft rays than other fish, and seven spotted grouper have more number of anal soft rays, and caudal fin rays than other fish (P < 0.05). Photographed under the x-ray, kelp grouper have the most curved vertebral column and largest swim bladder than other fishes (P < 0.05). Our results of this study confirmed that 3 subfamily fishes adequately can distinguish with external body shape, and we hope that the results of our study could be used to identify in Serranidae family as taxonomical parameters.

• 한국발생생물학회지:발생과생식
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• 제19권1호
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• pp.19-24
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• 2015

This study was conducted to determine the stress response [ethological (operculum movement number (OMN)), hematological (hematocrit and hemoglobin), biochemical (glucose, cortisol and glutamic oxaloacetic transaminase (GOT))] in red spotted grouper, Epinephelus akaara during exposure of different water temperature in winter season. This species (Total length, $18.56{\pm}0.34cm$) previously maintained in water temperature of $15^{\circ}C$ were transferred to 15, 20 and $25^{\circ}C$. During experimental period (7 days), OMN, hematocrit (Ht), glucose and GOT values were significantly high in $15^{\circ}C$ when compared to 20 and $25^{\circ}C$. Hemoglobin value was also increased at $15^{\circ}C$, but no significant differences. There was no differences in cortisol levels among the temperature groups. No fish mortality was observed during the experimental period. From these results, $15^{\circ}C$ is likely more stressful to red spotted grouper than $20^{\circ}C$ and $25^{\circ}C$. These observations confirm that red spotted grouper adapts better to temperatures between 20 and $25^{\circ}C$ during the winter season.

• 한국발생생물학회지:발생과생식
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• 제18권3호
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• pp.127-131
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• 2014

We investigated the androgenic effects of $17{\alpha}$-methyltestosterone (MT) on gonadal sex reversal in juvenile red spotted grouper Epinephelus akaara. The fish were immersed in $17{\alpha}$-MT at 1 and 5 mg/L. Treatment method of $17{\alpha}$-MT was once weekly for 4 and 8 weeks. Fish were sampled at 12 months after end of the treatment period in order to histological analysis. At the initiation of an experiment (70 day after hatching), juvenile red spotted grouper have the paired primordial gonads with somatic cells bellow kidney in the posterior portion of the body cavity. Formation of ovarian cavity indicates that the ovarian differentiation beginning at 70 DAH in red spotted grouper. At 12 months after end of the treatment period, control group, $17{\alpha}$-MT 1 mg/L treatment group for 4 and 8 weeks, and $17{\alpha}$-MT 5 mg/L treatment group for 4 weeks were all female. However, sex-changed males without ovarian cavity were observed in the $17{\alpha}$-MT 5 mg/L treatment group for 8 weeks. In grouper, we firstly reported that the red spotted grouper be able to induce the primary males by hormone treatment prior to gonadal sex differentiation.

• 한국어병학회지
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• 제34권1호
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• pp.99-104
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• 2021

In this study, we investigated safety and efficacy of a low temperature immunization protocol with NNV in red spotted grouper, Epinephelus akaara and long tooth grouper, Epinephelus bruneus and seven band grouper, Hyporthodus septemfasciatus. Further, growth rate between immunized and naïve fish was evaluated during the experiment to check side effect of immunization. Three grouper species were immunized by immersion method with live NNV at 10^5.0 TCID₅₀/mL at 16.5℃ for 30 min and reared for 120 days at natural sea water temperature. To evaluate growth rate, total length and wet weight was measured 7 times after immunization. Immunized three grouper species were challenged by intramuscular inoculation with NNV at 10^4.2 TCID₅₀/100 µL/fish. Immunization at low temperature with live NNV did not show any clinical symptoms of infection, mortality and inhibition of growth. After challenge, cumulative mortality of naïve seven band grouper, red spotted grouper, long tooth grouper were 45, 10, 20 %, respectively. However no mortality was observed at immunized groupers. Thus, it was demonstrated that immunization at low temperature with live NNV are able to protect three different species of groupers without inhibition of growth.

• 한국양식학회지
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• 제16권2호
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• pp.110-117
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• 2003

붉바리(E. akaara)의 뇌하수체에서 추출한 mRNA로부터 RACE 방법으로 cDNA를 cloning하고 염기서열을 분석하였다. 붉바리의 성장호르몬 cDNA는 5' UTR, open reading frame, 3' UTR이 각각 21 bp, 615 bp, 247 bp인 전체 883 bp로 구성되어있다. Adenylation signal로 작용하는 sequence인 AATAAA는 poly(A)로부터 20 bp upstream에 위치하는 것을 확인하였다. 염기서열을 바탕으로 추정한 성장호르몬은 204개의 아미노산으로 구성된 단백질로서 signal peptide(17 aa)와 mature protein(187 aa)을 포함하고 있으며 mature protein의 분자량은 21.3 kDa으로 나타났다. 이 호르몬은 단백질의 3차 구조에 중요한 이황화 결합을 할 수 있는 4개의 cysteine 잔기와 1개의 N-glycosylation site를 가지고 있었다. 붉바리 성장호르몬의 염기서열은 농어목에 속하는 다른 어류의 성장호르몬 염기서열과의 유사도가 높게 나타났으며 orange-spotted grouper, gilthead seabream과 각각 96.9%, 88.6%의 상동성을 보였다.

• Ocean and Polar Research
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• 제42권4호
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• pp.303-311
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• 2020

In this study, the embryonic development and hatchability of eggs fertilized by the reciprocal hybrids of kelp grouper (Epinephelus bruneus) and red-spotted grouper (E. akaara) were evaluated with the goal of establishing a novel hybrid with enhanced growth and viability during the farming period in the temperate waters of Korea. The fertilization rates were lower for hybrids than for maternal purebreds and were significantly higher in the red-spotted grouper ♀ × kelp grouper ♂ hybrid (RGKG, 89.61 ± 1.58%) than in the kelp grouper ♀ × red-spotted grouper ♂ hybrid (KGRG, 74.82 ± 4.23%, p < 0.05). Unlike the fertilization rates, the hatching rates of fertilized eggs were similar between hybrids and maternal purebreds and did not differ significantly between KGRG and RGKG (72.74 ± 3.60% vs. 75.23 ± 2.20%, respectively, p > 0.05). The embryonic development of the hybrids was similar to that of maternal purebreds; however, irregular cleavage and asymmetric blastoderm were noticeable in the developing eggs of KGRG hybrids. The deformity rates of newly hatched larvae were higher in hybrids than in maternal purebreds and were significantly higher in KGRG than in RGKG (17.47 ± 1.28% vs. 7.11 ± 0.54%, respectively, p < 0.05). These results demonstrate the potential to produce viable larvae from these two hybrids. Although the production efficiency of KGRG was lower than that of RGKG, the fertilization, hatching, and deformity rates make both hybrids useful for further comparative studies regarding economic aspects.

• 생명과학회지
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• 제24권6호
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• pp.626-632
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• 2014

한국산 붉바리 집단에서 유전적 구조와 계통 유연관계를 mtDNA COI 유전자 서열의 다형성을 이용하여 조사하였다. COI 유전자 서열을 결정하였고 기존에 보고된 서열들과 비교하였다. 본 연구를 통해 결정된 COI 서열들은 기존에 보고된 EF607565에 대하여 99.1-99.8%의 동일성을 나타내었다. 전체 20가지의 haplotype들이 발견되었고, 한국산 붉바리 집단은 19가지의 haplotype을 나타내었다. 이들 중 Hap_03과 Hap_08은 각각 제주도와 중국-특이적인 COI 서열들을 보였다. 반면, Hap_07은 한국에서 채집된 시료들과 홍콩과 대만에서 보고된 기록 등 여러 COI 서열들을 포함하였다. COI haplotype들의 다형성에 근거한 계통 유전학적 분석을 통해 작성된 NJ tree는 Epinephelus 속 내에서 단계통적인 분지양상을 나타내었고, 이는 붉바리 집단들이 공통의 모계 선조에서 진화한 것임을 나타내었다. 또한 중국해에서 보고된 COI 서열만을 포함하였던 Hap_08은 NJ tree의 중앙부에서 위치하였고, Hap_07의 서열들과도 근연의 관계임을 보여주었다. 이 결과는 중국산 붉바리 역시 동아시아의 다른 집단들과 모계적으로 연관되어있음을 보여주었다. 결과적으로, 동아시아 붉바리 집단들은 모계적으로 연관되어있을 뿐만 아니라 공통의 진화 역사를 공유하고 있으며 여전히 동아시아 해류(Kuroshio 해류)에 의해 영향을 받는 집단이라고 할 수 있다. 본 연구는 붉바리의 유전적 구조와 계통 유연관계를 이해하는 데 도움을 줄 수 있으며, 인공증식과 산업화에 관련된 연구에 있어 중요한 역할을 담당할 것으로 기대된다.

• Fisheries and Aquatic Sciences
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• 제23권2호
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• pp.4.1-4.9
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• 2020

Growth of fish is controlled by various environmental factors, including water temperature (WT). WT is also a major factor that affects the eating behavior of fish. In this study, we studied the relationship between WT and expression profiles of factors involved in appetite regulation and digestion in red spotted grouper. Fish were divided into three groups with 30 fish per group and reared for 2 weeks in a recirculating system at three different WT (natural WT, 20 ℃, and 25 ℃). After 2 weeks, they were sacrificed immediately after food intake (+ 0 h), 3 h after (+ 3 h), 6 h after (+ 6 h), and 3 h before being fed the next day (- 3 h). Fish samples were obtained for analysis of mRNA expression levels of cholecystokinin (CCK), leptin A (LepA), leptin B (LepB), and neuropeptide Y (NPY) in the brain, liver, and intestine. Expression of CCK and NPY mRNA was significantly higher at 25 ℃ compared to that at natural WT and 20 ℃, but no difference was observed for leptin. This suggests that the red spotted grouper shows characteristics typical of subtropical fish and has higher levels of feeding and digestion when reared at 25 ℃ water temperature condition.

• 한국발생생물학회지:발생과생식
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• 제24권3호
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• pp.225-230
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• 2020

This study reports the presence of mature and bi-sexual phase gonads in red spotted grouper, Epinephelus akaara after less than a year of cultivation in a commercial indoor tank and a net cage. In December 2018, juveniles were placed in an indoor tank and cultured for five months. In June 2019, the fish were transferred to a net cage and cultured until September. The rearing temperatures ranged from 19.86℃-24.65℃ in the indoor tank and 21.86℃-27.65℃ in the net cage. During the net cage culture period, specimens were randomly selected for histological gonad examination. The highest gonadosomatic index (GSI) value was measured in July (3.38±2.53), and dramatically decreased in August (0.44±0.21) and September (0.42±0.30). In July, some mature fish showed signs of vitellogenic stage oocyte development (vitellogenic and oil droplet stage oocytes), but immature fish were in an early developmental stage containing peri-nucleolus stage (PNS) oocytes. Bi-sexual phase gonads containing spermatocytes and spermatids were observed in the lumen and several PNS oocytes. By August and September, most specimens showed early-stage ovary development. However, mature testis (in August) and bi-sexual phase gonads (in September) were also observed. These results provide evidence for early puberty and hermaphroditism in the red spotted grouper.

• Fisheries and Aquatic Sciences
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• 제24권7호
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• pp.235-242
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• 2021

The present study investigated the critical thermal maxima (CT_max) of red-spotted grouper, Epinephelus akaara under different acclimation temperatures (T_acc). Fish were acclimated at 24℃, 28℃, and 32℃ water temperature for 2 weeks. Water temperature was increased at a rate of 1℃/h and CT_max level was measured following the critical thermal methodology (Paladino et al., 1980). The results showed that CT_max values of E. akaara were 35.61℃, 36.83℃, and 37.65℃ for fish acclimated at 24℃, 28℃, and 32℃, respectively. The acclimation response ratio (ARR) was 0.26. The CT_max values were significantly correlated with body size. Collectively, it is said that the CT_max value of red-spotted grouper can be affected by different adaptation temperature (24℃, 28℃, and 32℃) and the fish acclimated to a higher temperature has a higher CT_max level. Besides, the CT_max value of 35.61℃-37.65℃ indicating the upper thermal tolerance limit for E. akaara under different T_acc (24℃, 28℃, and 32℃). Understanding the thermal tolerance of E. akaara is of ecological importance in the conservation of this species.