• 수산해양교육연구
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• 제28권6호
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• pp.1792-1800
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• 2016

This study is aimed to analyze the profitability of flatfish fry production farms in the Republic of Korea. The continuous and stable production of flatfish fries is one of important factors that increases the possibility of flatfish aquaculture's success. It is also the basis of aquaculture industry that estimates the quantity and quality of fishery products from aquaculture. Based on the surveyed data, production values and costs of flatfish fry production are estimated and compared to determine the profitability of flatfish fry production by farm. Results show that average return on sales of farms is 21.2%(12.4~26.3%), indicating that flatfish fry production would be profitable under the current production and market conditions. Sensitivity analyses of main variables (survival rate and selling price) indicate that the profitability of flatfish fry production farms can be significantly decreased when the survival rate and selling price would be slightly decreased.

• Ocean and Polar Research
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• 제41권1호
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• pp.35-46
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• 2019

The purpose of this study is to identify factors influencing fish production of shallow-sea aquaculture in South Korea. This study employed the two-way fixed effect and random effect models based on the panel models and also the difference between GMM and system GMM models based on the dynamic panel models using the amount of fish farming production, the number of stocked fry, the number of cultured fish, the amount of inputted feed, the farming area, the number of workers, and the sales price data from 2010 to 2017. First, the two-way fixed effect model of the panel models was selected by panel characteristics, time characteristics and Hausman tests and also the model was statistically significant. As a result of the two-way fixed effect model, the number of stocked fry, the amount of inputted feed, and the number of workers were identified as factors that increase the fish production of shallow-sea aquaculture. However, the number of cultured fish and the sales price were analyzed as factors that reduce the fish production of shallow-sea aquaculture. Second, the system GMM model of the dynamic panel models was selected by Hansen test and Arellano-Bond test in order to identify whether or not the over-discrimination condition is appropriate. Based on the system GMM model, the number of stocked fry, the amount of inputted feed, the number of workers in this year and 1 year ago, the number of cultured fish 2 years ago, and the sale price 3 years ago were analyzed as factors that increase the fish production of shallow-sea aquaculture. However, the amount of fish farming production 1, 2, 3 years ago, the farming area in this year, and the number of cultured fish in this year and 1 year ago were identified as factors that reduce the fish production of shallow-sea aquaculture. In conclusion, this study suggests that it is desirable to control the amount of stocked fry rather than to expand the farming area for fish farming in shallow-sea aquaculture, so as to keep the sale price at a certain level by maintaining the appropriate amount of fish production.

• 한국수산과학회지
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• 제49권2호
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• pp.154-160
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• 2016

Several our studies have focused recently on the mass production of the freshwater Cladoceran Moina macrocopa which can substitute Artemia nauplii for the culture of larval marin fish. A 6 weeks experiment was conducted to investigate the effects of enrichment on the fatty acid composition of Moina macrocopa through feeding Schizochytrium sp. containing highly unsaturated fatty acids and to study the impacts of n-3-HUFA enriched Moina on improving survival rate and fatty acid compostion of larval rockfish Sebastes schlegeli. After feeding for 6 weeks, the Moina-fed fry resulted in a higher survival rate of 99.2% compared to the Artemia-fed fry 12.8%. In addition, the Moina-fed fry had the fast growth rate 45.6mm compare to the Artemia-fed fry 25.7 mm at the end of the experiment. The Moina-fed fry showed significantly higher level of 16.47% DHA than their Artemia-fed fry counterparts of the level of 3.97% with respect to DHA. PL, the cell membrane components in living food organisms, constituted 63.8% of the Moina, which was significantly higher than in the 40.1% of the Artemia. The present study indicate that Moina macrocopa can be used as Artemia substitute and improving the survival rate rockfish larvae through enchriment Schizochytrium sp.

• Fisheries and Aquatic Sciences
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• 제23권5호
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• pp.13.1-13.7
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• 2020

Stock enhancement is considered to be a valuable approach for restoring fishery resources. Because no specific official institution in Taiwan is responsible for the production of fry, the released fry are purchased directly from the private sector. However, fishermen from the private industry have not established a genetic background, so the genetic composition for each batch of released fry is unclear. Mangrove red snapper (Lutjanus argentimaculatus), a prominent species released in Taiwan, was collected after its official release. One hundred and two field samples were compared with four batches of hatchery fry (n = 685) by using a microsatellite-based multiplex PCR assay. Four of the field samples (3.9%; 4/102) were revealed to be from a fish farm and most likely from a single batch. This study revealed that wild mangrove red snappers are genetically different from those originating from farms, and their origins can be traced through molecular markers, even without information on breeding stocks.

• 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.

• 한국양식학회지
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• 제10권3호
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• pp.373-380
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• 1997

순환 여과 시스템에서 나일틸라피아의 종묘생산성을 향상시키기 위한 연구의 일환으로 암컷 친어의 크기, 친어 방양 관리 방법에 따른 생산성과 생산된 난의 인공부화 성공률을 조사하였다. 암컷 친어의 크기가 작고 (평균 어체중 : 340.0g) 방양 밀도가 낮을 때(1.2 kg m 상(-2))의 종묘 생산량이 크기가 크고 (평균 어체중: 611.5g) 방양 밀도가 높을 때 (2.1kg m 상(-2) 보다 유의하게 많은 것으로 조사되었다(P<0.05). 대량 종묘 생산에 있어서 구중 부화 중인 난과 난황 자어의 제거후 인공 부화를 통한 인공부화법 (clutch removal method)은 유영 자어의 수집에 의한 자연부화법 (natural mouthbrooding method)에 비해 총생산량, 단위 면적당 생산량, 암컷 마리당 생산량 및 암컷 단위 어체중당 생산량에서 유의하게 높은 것으로 조사되었다(P<0.05). 암컷 친어의 구강으로부터 제거한 알의 발생 단계별 인공 부화 실시 결과 55.7%-91.6%의 부화율을 보였다.

• 한국어류학회지
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• 제21권3호
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• pp.158-166
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• 2009

본 연구는 동갈돗돔의 양식생물학적 기초자료를 확보하고자 염분의 영향과 수온의 영향을 조사하였다. 염분의 경우 수정란의 부화와 부상률, 자어의 부상률 및 생존율, 치어의 성장과 생존에 미치는 영향을 조사하였다. 수온의 경우 일간 수온 변화 정도, 급성 저수온 충격, 완만한 수온 감소에 따른 생존, 먹이섭식 및 유영능력을 조사하였다. 염분의 영향에서 수정란의 부화율과 부상률 및 자어의 부상률과 생존율은 자연 해수 염분(32 psu)에 가까울수록 높게 나타났다. 치어의 성장과 생존의 경우에는 기수의 염분(5~20 psu)의 경우 해수 염분(25~32 psu)과 유의한 차이가 없었다. 다만 담수의 경우만 유의하게 낮았다. 수온의 영향에 관한 3가지 실험 모두에서 급성이던 만성이던 수온의 하락폭이 클수록 생존율, 먹이섭식 및 유영활동이 감소하는 것을 확인할 수 있었다. 결론적으로 본 실험을 통해 동갈돗돔은 성장과 생존은 일반 해수염분에서 가장 좋았고, 월동의 임계수온은 $8^{\circ}C$로 나타났다.

• 한국가축번식학회지
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• 제25권3호
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• pp.277-286
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• 2001

기존의 미세주입 및 정자 electroporation에 의한 보다 효율적인 유전자 도입방법을 개선하여 간단하고 고효율성의 유전자 변환기술을 위한 유전자 도입장치의 시제품 개발로 다수의 난자를 전기적으로 단순화할 수 있는 상업화의 가능성을 보여주었다. 도입된 유전자는 모든 초기배에서 발현됨을 보여 주었다. 특히 난황내의 합포체세포(syncytium)에서의 transient성의 강한 발현은 전기자극에 의해 많은 수의 난자에 유전자를 도입하고 100% 발현되는 체계를 이용하여 transient 시기에서 인간 유용단백질 생산의 가능성을 타진할 수 있는 결과를 보여 주었다. 어류유전자 발현의 작동되는가를 검색하기 위해 신경세로조직특이 tubulin promoter 를 이용한 결과 gfp의 발현이 뇌주변과 척추를 중심으로 체내 전반의 신경세포내에 발현이 강하게 나타남을 보여 주었다. 한편 reporter 유전자 이외에 간세포로부터 전체 RNA를 분리시켜 vitellogenin의 분해산물인 phosvitin cDNA의 길이와 promoter지역인 1.6 kb에 대한 primer쌍들을 선정한 상태에서 PCR에 의해 각각 cDNA와 gDNA로부터 cloning 중에 있으며 human factor Ⅶ과 epidermal growth factor, vitellogenin의 3종의 target 단백 질유전자를 구축 및 검정 화인 중에 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권2호
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• pp.264-271
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• 2011

The effect of replacement of fish meal (FM) in diets with sand smelt meal (SSM) on fatty acid composition of carp fry, Cyprinus carpio, was examined. Five isonitrogenous and isoenergetic (38% crude protein, $15.75\;kJ\;g^{-1}$) diets replacing 0, 25, 50, 75, and 100% FM protein by SSM protein were formulated. Each diet was randomly allocated to triplicate groups of fish in aquaria, and each aquarium was stocked with 20 fish (initial average weight of $0.300{\pm}0.65\;g\;fish^{-1}$). Fish were fed twice daily to apparent satiation for 13 weeks. Results indicated that final weight, specific growth rate and feed efficiency ratio of fish fed with different SSM replacement diets did not differ significantly (p>0.05) from fish fed the control diet, except for 100% SSM level. No significant differences were noted among experimental treatments on dry matter, protein, lipid and ash contents of the fish body composition (p>0.05). Fatty acid analysis showed that saturated fatty acids in fish muscle significantly decreased, but monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) did not change with increasing dietary SSM. However, some changes also could be observed for some particular fatty acids in experimental fish. For example, the amounts of 15:0, 17:0, 18:1n-7, 18:2n-6 and 22:5n-3 significantly increased, but 16:0, 18:1n-9, 18:3n-3 and 20:1 n-9 significantly decreased with increasing dietary SSM. Total n-6 PUFA increased with increasing dietary SSM, but total n-3 PUFA were not changed in muscle of fish fed the experimental diets. The ratio of n-3 to n-6 was not affected significantly in muscle of fish fed the experimental diets containing different proportions of SSM, including the control diet.

• 한국수산과학회지
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• 제5권2호
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• pp.45-49
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• 1972

1. Brachionus calyciflorus의 실외 시비 배양에서 $16m^2$의 콘크리이트 못에서 1ml당 약 100개체의 고밀도 배양이 가능하였으며, 발생 시작 후 $2\~3$일 째에 dipterex를 $0.16\~0.2ppm$유효 성분 농도로 살포하여 Daphnia등 다른 갑각류의 발생을 억제함으로써 약 2주일 동안 그 발생 상태를 유지할 수 있었다. 이 때 사용된 비료는 닭똥이 약 8kg이며, 수심은 30cm 전후로 하였다. 2. 수온 $20^{\circ}C$ 이하로 내려가면 그 발생이 극도로 저하한다. 3. Filinia longiseta등 소형 rotifer는 1ml당 약 1000개체의 고 밀도로 발생이 가능하나 dipterex에 대하여 대단히 약하며 앞으로 상세한 실험이 요청된다. 4. 실내에서 Brachionus calyciflorus를 배양할 때는 그 먹이인 녹조류를 실외의 못에서 배양하거나 또는 태양광선을 이용할 수 있는 장치를 실내에 하는 것이 좋다고 인정된다. 5. marble gourami의 어린 자어에 Brachionus calyciflorus를 먹이니 그 성장이 잘 되었다. 이 때 dipterex를 사용하여 다른 갑각류를 억제하면서 발생시킨 것을 바로 먹여서 자어에게 아무런 지장을 초래하지 않았다.