• 한국어류학회지
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• 제26권1호
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• pp.70-73
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• 2014

Interspecific hybrids between tiger grouper Epinephelus fuscoguttatus and giant grouper E. lanceolatus were genetically identified based on the partial sequence analysis of mitochondrial cytochrome c oxidase I (COX I) gene and nuclear recombination activating gene 2 (RAG 2) gene. Out of 585 base positions of RAG 2, a total of five nucleotide substitutions were detected between the two parental species (E. fuscoguttatus and E. lanceolatus). The hybrids had two distinct types of RAG 2 sequences corresponding to those of both parental species. Mitochondrial COX I gene sequencing showed that hybrids had sequences identical to E. fuscoguttatus. Molecular data clearly demonstrate that hybridization does occur between E. fuscoguttatus and E. lanceolatus, but with E. fuscoguttatus as the maternal parent.

• 수산해양교육연구
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• 제29권3호
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• pp.636-645
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• 2017

The physiological response of the longtooth grouper, Epinephelus bruneus to low water temperature (LWT) stress while on three different concentrations of dietary vitamin E (1 mg/diet g, 5 mg/diet g, and 10 mg /diet g) were investigated. Plasma cortisol, glucose, and aspartate aminotransferase (AST) levels were higher in the control and sham control compared with the vitamin E supplemented groups. The most addition with vitamin E in the diet (10 mg/diet g) showed the lowest levels of cortisol, glucose, and AST. However, plasma alanine aminotransferase (ALT) showed no significant differences across all experimental conditions (P>0.05). Also the more disposing vitamin E into feeding the better resistance against stress on the LWT was shown through cortisol, glucose, ALT, and AST.

• 한국수산과학회지
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• 제54권1호
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• pp.31-37
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• 2021

The mass production of fertilized eggs of the convict grouper Hyporthodus septemfasciatus was studied from 2013 to 2020 for industrial aquaculture. The experiment was divided into two groups. Group 1 broodstock was raised from wild-caught fry and used from 2013 to 2020. Group 2 broodstock was raised from artificially propagated fry and used from 2019 to 2020. Males used to collect sperm for artificial insemination weighed more than 7 kg. The effects of various hormones on artificial ovulation were investigated from 2013 onward. Among these, luteinizing hormone-releasing hormone analogue (LHRHa) at 100 ㎍/kg body weight showed the most effective results and was used for artificial egg collection from 2014 onward. In Group 1, the average total egg production per year, average egg production per individual, fertilization rate, and hatching rate were 26,143 mL, 609.7 mL, 93.3%, and 91.8%, respectively, and in Group 2, were 2,750 mL, 316.5 mL, 92.1%, and 90.4%, respectively. Based on these results, we showed that a large number of fertilized eggs for artificial seeding could be produced consistently. Moreover, the mass production of fertilized eggs in Group 2 establishes a foundation for the complete aquaculture cycle of H. septemfasciatus.

• 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.

• 한국수산과학회지
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• 제53권4호
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• pp.506-514
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• 2020

We investigated seed management and feeding regime of larval red spotted grouper Epinephelus akaara using live food organisms. Fertilized eggs were produced in March 2020 by manipulating photoperiod and water temperature. Broodstock (F0) produced approximately 0.30×10⁶ eggs, of which 0.25×10⁶ were fertilized; first-generation broodstock (F1) produced 2.00×10⁶ eggs, of which 1.90×10⁶ were fertilized. Larvae were reared at temperatures of 21.0-24.5℃. The feeding regime consisted of rotifers Artemia, and commercial pellet feed. From 5-8 days after hatching (dah), rotifers collected from high-density incubation tanks were fed to grouper larvae at a density of 10-20 individuals/mL. From 9-30 dah, rotifers collected from low-density incubation tanks were fed to larvae at a density of 10-20 individuals/mL. Newly hatched Artemia were provided from 20-24 dah and enriched Artemia from 25-50 dah. Commercial pellet feed was given starting at 13 dah. The average mouth size in hatchlings was 263.4±3.7 ㎛ at 5 dah, 406.7±21.0 ㎛ at 11 dah, and 856.9±136.6 ㎛ at 21 dah. At 1 dah, larvae had a mean total length of 1.95±0.06 mm. At 66 dah, the mean TL was 4.0 cm. The final number of surviving red spotted grouper larvae was 218,380 fishes.

• Fisheries and Aquatic Sciences
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• 제10권3호
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• pp.113-118
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• 2007

Bromophenols are a group of compounds found only in marine organisms. They accumulate and give a sea-like aroma to marine animals. Cultivated fishes generally contain low concentrations of bromophenols compared to wild fishes. Feeding cultivated fishes with bromophenol-containing seaweed could increase their bromophenol content and thus improve their flavor quality. We evaluated the effect of an experimental feed on the bromophenol content of green grouper, Epinephelus coioides, during an 8-week feeding period. Green grouper individuals were divided into two groups and fed with conventional feed or experimental feed containing dried seaweed. Fish were collected biweekly for 8 weeks for proximate analyses and bromophenol content evaluations. Bromophenols were extracted, identified, and quantified by gas chromatography-mass spectrometry. Both moisture and lipid contents were generally higher in the controls; however, total weight and protein content were higher in the experimental group. Only 2,4-dibromophenol and 2,4,6-tribromophenol were detected in the samples. Throughout the 8 weeks, 2,4,6-tribromophenol concentrations were higher in the experimental group (9.20-32.3 ng/g dry wt) than in the control group (7.33-18.79 ng/g dry wt), but no significant difference in 2,4-dibromophenol concentration was detected between the two groups. The total bromophenol content reached a maximum at week 4 for the experimental feed and week 6 for the control. In short, experimental feed that incorporated bromophenol-containing seaweed increased the total bromophenol content in the green grouper.

• 한국어병학회지
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• 제12권2호
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• pp.107-113
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• 1999

능성어의 바이러스성 신경괴사증 바이러스(fish nodavirus)의 병원성을 능성어 및 다른 해산어류를 대상으로 인위감염법에 의해 조사한 결과, 능성어 바이러스성 신경괴사증 바이러스는 능성어에서는 소형어(27 g)부터 대형어(104 g)까지 제사를 일으켜 강한 병원성을 나타냈지만, 실험에 사용한 크기의 방어(537 g), 참돔(207 g), 돌돔(43 g), 넙치(41 g), 자주복(27 g) 및 조피볼락(94 g)에는 폐사를 일으키지 않아 병원성을 나타내지 않았다. 그리고 사육수온별 능성어에 대한 바이러스의 병원성은 수온 $15^{\circ}C$에서는 병원성을 나타내지 않았고, 수온 $20\sim28^{\circ}C$에서는 수온이 높을 수록 병원성을 강하게 나타냈다. 그리고 바이러스는 근육주사, 복강 주사 및 경구감염뿐만 아니라 침지감염과 혼합사육감염에 의해서도 쉽게 능성어에 감염이 되지만, 감염 후 생존한 능성어에 대해서는 바이러스를 재감염시켜도 폐사가 일어나지 않았다.

• 한국어류학회지
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• 제31권1호
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• pp.23-29
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• 2019

이번 연구에서 바리과 어종의 새로운 교잡종을 생산하기 위한 연구의 일환으로 능성어 (Hyporthodus septemfasciatus) ♀${\times}$대왕바리 (Epinephelus lanceolatus) ♂ (CGGG)의 발생 양상, 부화율, 기형 발생률 그리고 부화 소요시간을 조사하고, 교잡종의 모계어종의 순종 (능성어 ♀${\times}$♂, CG)과 비교하였다. CGGG와 CG 수정란은 자외선 살균 해수가 채워진 5-L 용량의 비이커 9개에 3,000~5,000개/비이커의 밀도로 수용되었으며, 발생 기간 중 수온은 $23.5{\sim}24.8^{\circ}C$ 그리고 염분은 32.1~32.8 ppt 였다. CGGG의 수정률과 부화율은 각각 $69.4{\pm}1.5%$와 $59.0{\pm}5.1%$로서 CG에 비해 유의하게 낮았다 (p<0.05). CGGG는 비균등 난할, 배체 체형 기형 그리고 부화자어의 척추 기형이 높게 출현한 것을 제외하고, CG와 동일한 난발생 양상을 보였다. CGGG의 부화까지 소요 시간은 CG에 비해 약 2시간 느렸다(p<0.05). 이상의 결과에서 CGGG는 수정률, 부화율 그리고 기형률 등 발생능력이 CG에 비해 낮았지만 부화자어의 대량생산이 가능할 것으로 판단된다.

• Fisheries and Aquatic Sciences
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• 제21권7호
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• pp.25.1-25.6
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• 2018

The main objective of this study was to provide anesthetic criteria of clove oil for an effective manipulation and transportation of red spotted grouper, Epinephelus akaara. When anesthesia temperature (20, 24, and $28^{\circ}C$) and concentration of clove oil (25, 50, and 75 ppm) were increased, the anesthesia and recovery time decreased and tended to be similar to each other between juvenile and adult. Also, as the temperature and concentration increased, the ratio of exposure time and recovery time between juvenile and adult were decreased. When plasma cortisol concentrations were compared for 48 h after anesthesia with 50 ppm of clove oil, both the juvenile and adult fish grew up to 12 h; however, thereafter decreased and there was no significant difference from control at 48 h.

• 한국수산과학회지
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• 제50권5호
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• pp.527-533
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• 2017

We investigated the infection of nervous necrosis virus (NNV) in seven band grouper Hyporthodus septemfasciatus broodstocks, which have been reared in aquaculture farms in South Korea during 2012-2014. To investigate the prevalence of NNV within the broodstock, egg, sperm, and blood were sampled in the spawning season. The egg and sperm samples were subjected to a nested reverse transcription (RT) polymerase chain reaction (PCR) assay to detect NNV and were inoculated on SSN-1 cells to culture the virus. Blood samples were used to detect antibodies against NNV using enzyme linked immunosorbent assay (ELSIA). Positive values from ELISA were found in 39 of 162 samples (24%) in 2012, and 13 of 28 samples (46%) in 2014. Additionally, 4 of 34 broodstocks (11%) investigated in 2013-2014 were determined to be carriers from the nested RT-PCR and in vitro cultivation. The broodstocks in which antibodies against NNV were detected by ELISA, or in which NNV was detected by the nested RT-PCR assay, posed a risk of vertical transmission of NNV. Therefore, it is necessary to select virus-free broodstocks in seed production to reduce the possibility of the vertical transmission of NNV.