• 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.

• 한국발생생물학회지:발생과생식
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• 제25권2호
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• pp.75-82
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• 2021

We studied steroid metabolites produced from red-spotted grouper ovarian follicles during maturation. Oocytes with 350-500 ㎛ diameter were in vitro incubated in the presence of [³H] 17α-hydroxyprogesterone as a precursor. Steroid metabolites were extracted from incubated media and oocytes. The extracts were separated and identified using thin layer chromatography, high performance liquid chromatography and gas chromatography-mass spectrometry. The identified metabolites were androstenedione (A₄), testosterone (T) and estrone (E₁). The metabolites of A₄ was dominant in all size of oocytes and it was the highest in 480 ㎛ diameter oocytes. The metabolites of two progestins, 17α,20β-dihydroxy-4-pregnen-3-one and 17α,20α-dihydroxy-4-pregnen-3-one were detected in the oocytes less than 480 ㎛ diameter although they were not identified definitely. In the oocytes of 480 ㎛ diameter, metabolite of progestin was the highest, and germinal vesicle (GV) was still in the middle of cytoplasm. In the oocytes of 500 ㎛ diameter, GV was began to migrate and the major metabolites were A₄ and E₁. The metabolite of E₁ was detected in all size of oocytes and it was higher than that of E₂. These results suggest that oocytes of 480 ㎛ diameter are the transitional stage involving steroidogenic shift to final oocyte maturation and potential function of E₁ during maturation process.

• 한국어류학회지
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• 제29권1호
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• pp.13-21
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• 2017

본 연구는 능성어(Epinephelus septemfasciatus)를 해수 순환여과양식시스템(RAS)에 적용하는데 문제가 되는 암모니아의 농도 기준을 제시하기 위하여 96시간 동안 암모니아 노출에 따른 생존율 및 혈액학적 특성 변화를 조사하였다. 생존율 실험구의 암모니아 농도는 대조구, 0.35, 0.4, 0.5, 0.8 mg/L였으며, 96-h $LC_{50}$ 농도는 0.6 mg/L로 나타났다. 능성어 치어의 암모니아 96-h $LC_{50}$ 농도인 0.6 mg/L에서 0, 3, 6, 12, 24, 48, 72, 96시간 간격으로 12마리씩 혈액 샘플링을 하였다. 실험구의 암모니아 노출 시간이 경과할수록 혈장 코티졸, 글루코스, GOT 및 GPT 농도가 증가하는 경향을 보였다. 혈장 암모니아와 총 단백질은 암모니아 노출 12시간째까지는 증가하였고 이후로는 감소하였지만, 대조구와 비교하여 유의하게 높은 값을 나타내었다. 또한 혈장 전해질이온($Na^+$, $Cl^-$)과 삼투압은 감소하는 경향이 관찰되었다.

• 한국어병학회지
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• 제11권2호
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• pp.97-104
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• 1998

1989년부터 남해안 일원 해상 가두리 양식장에서 사육중이던 능성어가 고수온기에 대량폐사하여 폐사율이 80%이었다. 발병한 병어는 채색흑화, 안구돌출, 평행감각 상실,회전운동과 몸통이 휘어지는 증상을 나타냈고, 조직학적으로는 뇌조직 및 안구망막의 신경세포가 공포 또는 괴사되었다. 병어로 부터 어류주화세포를 이용한 세포배양법으로 원인 바이러스는 분리되지 않았지만, 뇌 신경세포의 세포질에서 크기가 약 30 nm이며 외막(envelop)이 없는 다면체 모양의 바이러스 입자가 전가현미경적으로 관찰 되었다. 능성어로 부터 분리된 바이러스는 에테르나 열($50^{\circ}C$, 30분)처리에 의해 병원성이 실활되지 않았으나, 강산(pH 3)이나 강알카리(pH 11)에는 부분적으로 병원성이 실활되었다. 그리고 fish nodavirus인 Striped Jack Nervous Necrosis Virus(SJNNV)의 primer를 이용하여 인위감염 및 자연감염된 능성어를 대상으로 PCR을 한 결과 감염된 능성어의 뇌 및 안구조직에서 악 430 bp정도의 PCR 증폭산물이 검출되므로서 능성어를 폐사시키는 원인 바이러스는 SJNNV와 아주 유사한 nodavirus 였다.

• Ocean and Polar Research
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• 제40권3호
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• pp.161-167
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• 2018

We examined the effect of salinity and water temperature on hatching and survival rates of fertilized eggs of hybrid grouper (Epinephelus fuscoguttatus ♀ ${\times}$ E. lanceolatus ♂) at different developmental stages, determining optimal conditions for their long-distance transportation. Deformities and hatching rates of fertilized grouper eggs were observed at salinities of 24, 27, 30, 33, 36, and 39 psu. The optimal salinity was determined to be 36 psu, with a survival rate of $70.0{\pm}2.0%$. Transportation experiments at 36 psu were conducted at water temperatures of 21, 24, 27, and $30^{\circ}C$, different developmental stages such as morula, 5-myomere, and tail beating for hatching and survival rates. The optimal water temperature and developmental stage for transporatation were $30^{\circ}C$ and tail beating stage and those hatching rates were $50.6{\pm}1.9%$ and $86.3{\pm}1.3%$, respectively. At $21^{\circ}C$, the survival rate by transportation water temperature was highest ($73.1{\pm}10.6%$), but the hatching rate ($17.1{\pm}3.1%$) was lowest. Therefore, the hybrid grouper fertilized eggs (E. fuscoguttatus ♀ ${\times}$ E. lanceolatus ♂) can be most efficiently produced under long-distance transportation conditions during the tail beating stage and at a water temperature of $30^{\circ}C$.

• 한국양식학회지
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• 제10권1호
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• pp.55-61
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• 1997

이 실험은 능성어의 친어관리와 종묘생산을 위한 연구의 일환으로 HCG 처리에 의한 난의 성숙과 배란유도를 알아보고자 행하였다. 제주대학교 해양연구소와 한라수산에서 1996년 6월에서 8월에 걸쳐 300-400 g, 1,500-2,000 g, 2,500-4,000 g 되는 능성어를 대상으로 하여 HCG를 500-1,000 IU/kg 체중농도로 2-3회 처리하였다. 이들의 생식소 발달은 일반적인 paraffin 절편법에 의하여 haematoxylin과 eosin으로 비교염색하여 조사하였다. 체중 300-400 g, 1,500-2,000 g, 2,500-3,200 g 되는 능성어에 HCG를 500-1,000 IU/kg 체중농도로 2-3회 처리한 결과 생식소는 난원세포군, 20~$30\mu$m 내외의 어린 난모세포를 가지고 있었다. 그러나 체중 3,400-4,000 g 되는 능성어에 HCG 1,000 IU/kg 농도로 2회 처리한 결과 난경 ~$800\mu$m되는 건강한 난과 퇴행란이 배란되었다. 체중 4,000 g 개체에서 배란된 난수는 4,252개 였으며, 이 중에서 건강한 난은 20.8%, 퇴행란은 79.2%였다. 그리고 생식소내에는 배란 흔적과 함께 난경 ~$50\mu$m전후의 주변인기 난모세포, 20~$30\mu$m의 어린 난모세포들이 차지하고 있다.

• 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.

• 자원ㆍ환경경제연구
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• 제12권4호
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• pp.663-686
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• 2003

본 연구는 미국 멕시코만의 Yellowedge Grouper 어업을 사례로 생물경제학 모델을 이용하여 자원회복계획 하의 총 허용어획량(TAC) 어업관리정책 효과를 분석하였다. 생물학적 자원평가모델인 잉여생산량 모델의 추정 결과 자원이 남획상태인 것으로 나타났고, 그 결과 10년 기간 동안 TAC제도를 이용하여 목표 자원량 달성을 위한 자원회복계획이 수립되어졌다. 모델 분석 결과, 통제관리가 잘 이루어진다면 자원회복기간 이후에 목표 자원량 수준이 달성되는 것으로 분석되었다. 하지만, 목표 자원량 달성을 위해서는 자원회복기간 동안의 어획량이 크게 감소되어야 하는 것으로 나타났는데, 특히 NMFS가 권고한 연간 342톤 어획량보다 더 크게 어획량이 감소해야 하는 것으로 분석되었다. 향후 25년 동안 발생할 어업 이익은 자원회복기간 동안의 어획량 감소로 인하여 현 상태유지 하에서보다 적은 것으로 나타났다. 그리고 사회적 할인율이 낮을 때는 변동어획량 TAC제도 하에서 고정어획량 TAC재도 하에서보다 큰 어업이익이 발생하였지만, 할인율이 높아질수록 고정어획량 TAC제도 하에서 변동어획량 TAC제도 하에서보다 큰 어업이익이 발생하였다.

• 한국발생생물학회지:발생과생식
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• 제17권2호
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• pp.79-85
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• 2013

To understand the sex reversal characteristics in the longtooth grouper (Epinephelus bruneus), this study examined the sex reversal and artificial masculinization of wild caught E. bruneus reared in indoor rearing tank after a 17${\alpha}$-methyltestosterone injection. To domesticate a broodstock, 64 wild caught E. bruneus, between 47.0 to 110.0 cm in total length and from 1.5 to 21.4 kg in body weight, were reared in indoor rearing tank (4.0 to 5.0 m wide, and 2.5 to 3.0 m depth) for four years. Seven specimens showed sex reversal from female to male during indoor rearing condition, whose total length and body weights were from 63.0 to 99.0 cm and from 4.4 to 13.2 kg, respectively. After inducing artificial masculinization in 14 female E. bruneus with a 17${\alpha}$-methyltestosterone (2.0 mg/kg BW) implants for 3 years, spermiation occurred in 9 specimens (total length: 54.0 to 68.0 cm, body weight: 2.3 to 4.3 kg). Among the female to male sex reversals, two specimens returned back to being female, whose body weights were 2.8 kg (initially 2.6 kg) and 2.7 kg (initially 2.3 kg). Therefore, this study suggested that E. bruneus (> 3.0 kg) was more effective in masculinizing by 17${\alpha}$-methyltestosterone implants.

• Fisheries and Aquatic Sciences
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• 제14권1호
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• pp.11-15
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• 2011

We examined the effects of 17${\alpha}$-methyltestosterone (MT) on growth and induced sex change in the longtooth grouper Epinephelus bruneus. The growth rate for body weight (GRW) and specific growth rate (SGR) of the group injected with MT over 8 weeks were significantly higher than those of the sham-injected control group, the group injected over 4 weeks, and the control group. Of the orally administrated groups, the GRWs of the control group and the group given 1 kg of feed with 2.0 mg of MT were highest and did not significantly differ from one another. For SGR, the treatment groups differed significantly, and the SGR of the control group was higher than those of the other groups (P<0.05). The condition factor (CF) of the group injected over 4 weeks was higher than those injected over 8 weeks, the sham-injected control group over 8 weeks, and the control group. The CF did not significantly differ between the sham-injected control group over 8 weeks and the injected group over 8 weeks, but these two groups differed from the control group (P<0.05). The CFs of the groups given 1 kg of feed with 0.5, 1.0, and 2.0 mg of MT were significantly higher than that of the control group (P<0.05). The feed efficiency ratio was not significantly affected by MT administration. Most of the experimental groups receiving MT developed many unidentified germ cell cysts and perinucleolus oocytes, although neither spermazoa cells nor sex-changed males were observed in any of the treatments.