• Fisheries and Aquatic Sciences
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• 제15권3호
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• pp.221-231
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• 2012

The marine medaka Oryzias dancena choriogenin H gene (odChgH) and its mRNA expression during estradiol-$17{\beta}$ (E2) exposure were characterized. At the amino acid level, the choriogenin H protein is predicted to possess the conserved repetitive N-terminal region, as well as zona pellucida (ZP) and Trefoil factor family (TFF) domains. At the genomic level, odChgH has an eight-exon organization with a distribution pattern of transcription factor binding sites in the 5'-upstream region, which is commonly found in other estrogen-responsive genes. The tissue distribution pattern of odChgH mRNA was found to be gender-specific, whereby females showed a higher expression level and wider tissue distribution than did males. During embryonic development, odChgH mRNA was robustly detected from the stage of visceral blood vessel formation. Experimental E2 exposure of males resulted in odChgH mRNA being induced not only in the liver, but also in other several tissues. The E2-mediated induction was fairly dose-dependent. The basal expression levels of hepatic odChgH mRNA were lower in males that were acclimated to 30 ppt salinity than in those acclimated to 0 or 15 ppt salinity. In contrast, the inducibility of odChgH mRNA during E2 exposure was greater in seawater-acclimated fish than in brackish water- or freshwater-acclimated fish.

• 수산경영론집
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• 제44권2호
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• pp.19-33
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• 2013

China is the world's largest producer of aquatic products and its fishery sector is comprised primarily of aquaculture facilities, both fresh and seawater, and a much smaller wild catch component. The expansion of the aquaculture sector continues to boost China's aquatic output. The increase is attributable to several factors. Among them rapidly growing domestic demand is no doubt one of the most important reasons. Rapid economic growth and rising disposable income are influencing domestic consumption and the economic recovery of major import markets is further stimulating consumption of China's aquatic products. This paper tries to examine the status, trend and reasons of consumption of aquatic products in China. Based on the analysis on the consumption of aquatic products and its change, this paper utilizes panel regression model to estimate the affecting factors of aquatic products consumption in China. By using panel data between 1997 and 2010, the results indicate that income, urbanization, aging and dummy variable have positive effects and fish price index has negative effect on China's aquatic products consumption as predicted. However, effects of meat consumption and education on fishery consumption are totally opposite with our predictions. In other words, it turns out that meat consumption has positive effect on fish consumption while education turns out to have negative effect. Finally the member of household does not show any significant effect on consumption of aquatic products in China.

• 한국양식학회지
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• 제10권1호
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• pp.1-7
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• 1997

남해 가두리 양식장에서 사육중인 전장 16.3~20.1 cm 크기의 돌돔 표피에 Monogenoidae, Benedenia sp. 가 10~31마리 기생되었다. 이 기생충의 감염률과 상대 감염밀도는 100%, 16.5 이었다. 기생 부위는 몸통 표피에 81.8%, 꼬리 부분에 16.5%, 기타 부위에 1.6%이었다. 기생된 부위는 출혈과 함께 점액이 다량 분비되었고, 궤양도 형성되었다. 이 기생충은 포르말린 250 ppm에서 10분, 200 ppm에서 20분, 150 ppm에서 20분만에 탈락 폐사되었으며, 담수욕 처리에서는 담수 100%에서 9분, 70%에서 20분만에 구제되었다. 기생충 구제를 위한 포르말린 처리에서 포르말린 독성에 의한 돌돔 폐사는 없었다. 그러나 담수 100% 시험구에서 중증어(기생충 대량 감염에 의한 점액 분비, 출혈, 궤양) 1마리가 폐사되었는데 이것은 삼투압조절 상실 때문이라고 여겨진다.

• 한국수산과학회지
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• 제34권5호
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• pp.465-472
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• 2001

양식현장에서 선별작업시 처리되는 사육수조의 수심감소와 어류이송에 따른 넙치 (대, 소)와 큰민어의 스트레스 반응을 알아보기 위하여 스트레스 지표로 알려져 있는 혈액학적 요인, 코티졸, 글루코스, 젖산 및 삼투질 농도를 조사하였다. 수심감소에서 넙치대의 Ht는 실험전 $14.6\%$였던 것이 10시간째까지 계속 높아져 $23.5\%$를 보였으나, 실험종료시 (46시간째) $14.4\%$로 회복되었다. 넙치대의 코티졸 농도는 실험개시시에 1.9ng/mL였던 것이 22시간째에 13.7 ng/mL로 높아졌고, 46시간째에는 4.0ng/mL로서 개시시의 수준으로 회복되었다. 큰민어는 4시간째 282.3ng/mL, 22시간째 350.5ng/mL로 높아졌으나, 실험종료시에는 16.0ng/mL로 낮아졌다. 큰민어의 글루코스는 실험개시시 57.0mg/dL로부터 22시간째에는 138.0mg/dL조 유의하게 높아졌다 젖산은 모든 어종에서 유의차가 인정되지 않았다. 어류이송에 따른 넙치대의 RBC는 실험개시시의 $1.9\times10^6 cell/{\mu}L$로부터 실험종료시의 $4.2\times10^6 cell/{\mu}L$로 높아졌다. 큰민어의 Hb는 실험개시시의 9.8g/dL로부터 실험종료시에 20.4g/dL로 개시시 보다 유의하게 높았다. 넙치대의 코티졸 농도는 실험개시시의 1.2ng/mL로부터 이동 1시간째에 95.3ng/mL로 높아졌고, 큰민어도 실험개시시의 5.5ng/mL로부터 1시간째에 175.5ng/mL로 높아졌다. 큰민어의 글루코스는 1, 3시간째 각각 132.5 mg/dL, 129.5 mg/dL로 실험개시시 46.5 mg/dL 보다 높은 수준을 보였다.

• 해양환경안전학회지
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• 제19권3호
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• pp.241-247
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• 2013

Yellow clay dispersion has been applied to minimize fisheries impact by the red tide Cochlodinium polykrikoides blooms in Korean coasts since 1995. The present preliminary study documents the effect of yellow clay on Korean rockfish, Sebastes schlegelii, in terms of oxygen consumption rate (OCR). The OCR in the low clay suspension (0.05 and 0.23 %, w/w) showed normal level compared to the control. In contrast, the OCR for each one of three replicates in the high clay suspension (1.16 and 5.58 %, w/w) was not returned to the previous level that clay was not treated, indicating that high clay suspension (${\geq}1.16%$, w/w) might give negative effect on Korean rockfish. Overall, this result suggests that field application of clay to control Harmful Algal Blooms (HABs) may not give impact on Korean rockfish once the clay is dispersed in a low concentration (${\leq}0.23%$). In order to understand the changes of OCR in the repeated exposure to clay, it is required to do further studies on the changes of OCR when the fish is exposed to clay repeatedly after recovery in the normal seawater.

• 수산해양교육연구
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• 제25권4호
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• pp.828-835
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• 2013

Products from aquaculture have sometimes been focused on the problems caused by the contamination of chemical agents as the use of chemical agents in aquaculture has been annually increased. The risk of contamination of products by chemical agents is greater in freshwater than in seawater. In order to evaluate the food safety of a fish grown in freshwater, we investigated the residues of antibiotics (tetracycline, oxolinic acid and ciplofloxacin) and malachite green in cultured rainbow trout, Oncorhynchus mykiss. Malachite green, which was prohibited in the application of aquaculture, was not detected in samples tested in this study. The residual content of tetracycline was determined to be less than the permissible amount, <0.2 mg/kg. The contents of ciplofloxacin was also less than the permissible amount, <0.1 mg/kg. However, in case of oxolinic acid, one of samples was only exhibited higher content than the permissible amount (<0.1 mg/kg). The results obtained in this study suggested that the control and regulation of chemical agents such as antibiotics was important to maintain a safe and worry-free seafood supply.

• 한국수산과학회지
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• 제29권6호
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• pp.828-836
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• 1996

The histological changes of gill, liver, spleen and muscle, and respiration and blood variables and liver glycogen content were examined in black seabream, Acanthopagrus schlegeli. Fish were exposed to a high level of total ammonia nitrogen (10.4 mg/l) and recovered from exposure $(0.4{\pm}0.2mg/l)$ in a closed recirculating seawater system. In the process of exposure, mortality was $9\%$, and hyperplasia, necrosis or inflammation appeared in all tissues except for muscle. Oxygen consumption was decreased by $49\%$, and red blood cell (RBC) number, hematocrit and hemoglobin concentration were significantly decreased, while plasma glucose contents, activities of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) increased. Liver glycogen content significantly increased from $6.6\%\;to\;10.4\%$. A large amount of hemosiderin was observed in the splenic tissue. During the recovery period, RBC number, hematocrit, hemoglobin concentration, GOT and GPT activities were returned to the normal status. Histological status of liver tissue was returned to the normal, but liver glycogen content was not recovered. During the recovery period, spleen melanin-macrophages temporarily increased, but subsequently decreased to the normal status.

• 한국수산과학회지
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• 제36권5호
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• pp.469-473
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• 2003

Transplantation of Sargassum horneri to natural substrate using the rope seeding method was undertaken. Seeding of S. horneri was grown on net in an indoor tank up to 0.2-0.3 cm in frond length for 2 months, and then transplanted to an architecture tile $(10\times10\;cm)$ with underwater glue and an iron pipe. After two months, number of S. horneri on the tile decreased because of grazing by herbivores. However, S. horneri on the iron pipe grew up to 0.5-2.0 cm in frond length. After 7 months, they rapidly grew up to a frond length of 11.0-203.0 cm with a mean frond length of 122.6 cm. S. horneri grew up to a maximum frond length of 313.0 cm, and mean frond length of 228.0 cm, after 10 months. The artificial S. hornevi beds can be used to clean the seawater and also be utilized as a source of marine biomass as well as for supplying habitat, shelter and spawning beds for fish and invertebrates.

• 수산해양기술연구
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• 제52권3호
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• pp.271-275
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• 2016

Recently, pollution problem in coastal water has become more serious and pollution including red tide serves as a main reason for reduction of fishes resources. Particularly, nutrients such as nitrogen and phosphorus are the most serious pollutants. Normally, biological wastewater treatment process is used in removing such nutrients. However, it is difficult to adopt the biological wastewater treatment process to a small-scale fish processing factory in case of using seawater as wash water. Thus, removing nutrients through struvite crystallization is investigated in this study for treating shrimp processing wastewater. Experiments were conducted by varying molar ratio of $Mg^{2+}:NH^4-N:PO^4-P$ from 1:1:1 to 2:1:1. It can be concluded that optimum molar ratio is 1:1:1. Struvite crystallization process is compared with chemical coagulation process using PAC and struvite crystallization process is proven as the more effective process in removing nutrients from wastewater. In view of results obtained from these experiments, struvite crystallization process is a promising method in removing nitrogen and phosphorus from wastewater; however, not so good in removing organics. Thus, struvite crystallization process is suitable as the pre-treatment process in treating shrimp processing wastewater and additional biological process is needed to remove organics.

• 한국수산과학회지
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• 제46권3호
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• pp.252-258
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• 2013

The quality and quantity of food organisms in fish seed production are important. The marine microalgae Nannochloropsis oculata are used as initial food organisms in the field. We investigated the effects of salinity (0, 10, 20, 30, 40 and 50 psu) on the lipid and fatty acid composition of N. oculata. Cultivation of N. oculata at varying salinities showed the highest growth rate at 20 psu. Total lipid content ranged from 17.26 to 18.63% at salinities from 0 to 50 psu). The nonpolar lipid content increased markedly at 30 psu and was highest at 15.55%. The polar lipid content was lowest at 30 psu, by 84.45%. It was also found that the omega-3 and EPA contents were inversely proportional to salt concentration. For the polar and nonpolar lipid compositions, there was no significant effect of salinity. Omega-3 polyunsaturated fatty acid content especially the content of EPA in the seawater larvae is the essential fatty acid in this food organism. It is thus advantageous to culture N. oculata at 20 psu.