• 수산해양기술연구
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• 제58권4호
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• pp.310-316
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• 2022

Giant pacific octopus, Enteroctopus dofleini, is a large mollusk distributed in the East Sea of Korea. In this study, the catch status of giant pacific octopus by drift line fishery and the effect of sea temperature on fishing ground were investigated in Goseong-gun, Gangwon-do, which is the central coast of the East Sea. The average catch of giant pacific octopus in Gangwon-do was 1,570 tons over the past ten years, and it accounted for 21% in 2008 and 44% in 2021 compared to the total catch in the East Sea during the same period. Such data indicates that the catch in Gangwon-do has recently increased. In this study area, giant pacific octopus weighing 1.1-5.0 kg dominated accounting for 56% of the total individuals, and followed by those weighing 1 kg or less. However, the ratio of catch of giant pacific octopus over 5.1 kg tended to increase in 2021, which is thought to be related to the sea temperature that affected the fishing ground. The main depth of fishing ground was from 21 m to 50 m in this area and fishing grounds were widely distributed throughout the season except summer. Fishing ground was formed with the conditions of bottom sea temperature under 10℃ and was diminished by moving of giant pacific octopus to deeper depth with conditions of bottom sea temperature over 18℃.

• 공업화학
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• 제30권5호
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• pp.639-642
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• 2019

본 연구에서는 침전법을 이용하여 양이온성 계면활성제인 hexadecyltrimethylammonium chloride (CTAC)를 도입한 수산화인회석을 합성하였다. X-선 회절 분석법과 투과전자현미경, 비표면적 분석기를 이용하여 수산화인회석과 CTAC을 도입한 수산화인회석의 결정성, 형태, 비표면적을 분석하였다. 열처리 후, HAP와 CTAC-HAP는 열처리 전과 비교하여 비표면적이 감소하였다. 또한 열처리는 뾰족한 막대 모양에서 종횡비가 감소한 둥근 모양으로의 CTAC-HAP의 형태변화를 유도하였다. 이러한 형태의 변화는 순수한 HAP에서도 관찰되었다. 그러므로 형태 변화와 열처리 후의 비표면적 감소는 열처리 중 CTAC의 제거로 생성된 기공들이 형태 변화로 인해 유지되지 않는 것으로 판단된다.

• 한국수산과학회지
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• 제52권5호
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• pp.539-546
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• 2019

The major cultured marine fishes in sea off the coast Gyeongsangnam-do Province, South Korea, were assessed and included 9.3% rockfish Sebastes schlegelii, 7.8% red seabream Pagrus major, and 2.1% rock bream Oplegnathus fasciatus. The number of insurance payments related to disease mortality in cultured fish in 2017 was fourfold that in 2016. Economic loss in aquaculture due to disease in cultured fish is high and represents an important inhibitory factor affecting marine fishery productivity. In 2018, diseases led to severe production losses in several aquaculture species: 40.0% in rockfish, 11.4% in olive flounder Paralichthys olivaceus, 10.0% in filefish Thamnaconus modestus, and 9.3% in red seabream. Fish-parasitic pathogens such as Microcotyle sebastis, Alella spp., and Dactylogyrus spp. enter mainly via the gills and skin surface. Among bacterial pathogens, Vibrio species were most common, with Vibrio harveyi being the dominant species causing infections in these fishes. The bacterium Lactococcus garvieae is thought to exhibit host specificity in fish. The fish species in the present study exhibited a higher tendency for infection by heterologous pathogens than by a single pathogen; therefore, it is necessary to devise new strategies for treating diseases in cultured fish.

• 한국어류학회지
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• 제34권2호
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• pp.133-137
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• 2022

동갈돔과에 속하는 Apogon unicolor 2개체(표준체장 81.0, 96.3 mm)가 제주도 차귀도 연안 자망에서 처음으로 채집되었다. 이 종은 측선공수가 26개, 첫 번째 등지느러미수가 6개, 새파수 11개(2+1+8)이며, 안하골과 전새개골의 가장자리에 거치상이 있고, 체측에 무늬나 반점이 없다. 이번에 채집된 표본은 형태와 분자유전학적 특징이 기존의 보고와 잘 일치하였으며 채색에 있어서 몸체와 지느러미가 전반적으로 홍색을 짙게 띠고 있어 이 종의 국명을 "진홍얼게비늘"로 제안한다.

• 수산경영론집
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• 제53권4호
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• pp.069-078
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• 2022

This study studied the characteristics of cultured oyster marketing in Sacheon Bay. The results of this study are summarized as follows. First, the GULDAE aquaculture is a unique production method of Sacheon Bay. Second, oysters in Sacheon Bay were low in production, but the price was more than 70% higher than in other producing areas. Third, profit is 12.5% higher and rate of return was 179.8%. Fourth, there were more out-of-market sales than other than other producing areas, and it is a bidding method. Fifth, the marketing cost was higher than the longline hanging aquaculture; however, the advantage of price offseted this point. Although the Sacheon Bay Oyster aquaculture is small, it was confirmed that it was a producing area with high profitability and a unique marketing form from other regions. Although the Sacheon Bay Oyster culture is small, it has been confirmed that it is a producing area with high profitability and shows a unique distribution form.

• 수산해양기술연구
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• 제58권4호
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• pp.345-351
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• 2022

In this study, the target strength for multi-frequency (38 kHz, 120 kHz, 200 kHz) of juvenile silverfish (Pleuragramma antarcticum) was estimated using by the KRM (Kirchhoff-ray mode) model. The body shape of the silverfish was described by a picture and the body length of nine individuals ranged in 1.8 cm to 8.8 cm. The maximum TS_cm according to the total length for the constant term (b20) was -92.93 dB at 38 kHz, -86.63 dB at 120 kHz, and -85.89 dB at 200 kHz, respectively. The averaged TS_cm according to total length for the constant term (b20) was -100.0 dB at 38 kHz, -93.0 dB at 120 kHz, and -106.9 dB at 200 kHz, respectively.

• 한국수산과학회지
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• 제56권6호
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• pp.899-908
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• 2023

Droughts can alter the dynamics of aquatic ecosystems, including fish communities. This study compared the variations in fish communities in Juam reservoir before and after drought events. Fish sampling was conducted five times from April 2021 to April 2023 using three different sampling methods (kick net, cast net, and gill net). The water level in the reservoir reached its peak (103.73 EL.m, 62.2% capacity) in September 2021, before the drought, and dropped to its lowest point (88.84 EL.m, 17.6% capacity) in April 2023. The dissolved oxygen content in the reservoir decreased from 27 to 6.3 mg/L between the period with the lowest water level (April 2023) and the period with the highest water level (September 2021). In September 2021, 466 fish were collected, but after one year of drought, the number of individuals decreased to 105. Further, the number of fish collected and water levels were positively correlated. Dominant species exhibited a population decline of over 60% with decreasing water levels. These findings highlight the importance of fishery resource management during drought periods.

• 한국수산과학회지
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• 제56권5호
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• pp.741-748
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• 2023

This study evaluated the supplemental effects of linseed oil (LO) as a substitute for docosahexaenoic acid oil (DHAO) in the diet of juvenile Atlantic bluefin tuna. A control diet (DHA) was formulated to contain 65% enzyme-treated fish meal and 3% of DHAO. A LO diet was formulated to contain 1% LO replacing 1% DHAO in DHA diet. In a feeding trial, 300 juvenile bluefin tuna (initial body weight 1.15 g) were randomly divided into two concrete tanks (70 ton capacity) and fed one of the experimental diets for 13 days. Weight gain was higher in the LO group (519%) than in the control (443%) while survival and protein digestibility were similar between groups. The biological assessment of the tuna digestive organs did not differ between the DHA and LO groups. The fatty acid composition of the carcass showed that α-linolenic acid was only observed in the LO group, and there was no difference in the composition of eicosapentaenoic acid and docosapentaenoic acid between the groups. These results indicate that LO could be a dietary good oil source for Atlantic bluefin tuna without apparent negative effects.

• 생명과학회지
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• 제28권12호
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• pp.1424-1431
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• 2018

본 연구에서는 BFT (biofloc technology) system 수조로부터 분리된 미생물(Bacillus sp.)을 이용하여 Marine snow와 유사한 유기물 분해산물을 만들어 뱀장어 자어먹이로 활용 가능성을 조사하였다. 유기원으로는 계란, 참다랑어, 뱀장어, 담치, 갯지렁이, 멍게, 바지락 그리고 새우를 이용하여 8 종류의 유기물 분해산물(HE, TM, EM, PC, TA, MS, HA, SP)를 생산했다. 생산된 유기물 분해산물은 특정한 형태는 나타나지 않았으며, 크기도 $10-20{\mu}m$의 미세한 것부터 $100{\mu}m$ 이상 되는 것까지 다양하였다. 부화 후 20일부터 다양한 유기물 분해산물을 이용하여 제조한 4 종류의 먹이(A, B, C, D-type)를 급이한 결과 A, B, C-type의 먹이를 급이한 뱀장어 유생은 각각 부화 후 37일, 39일, 37일까지 생존하였으나, D-type의 먹이를 급히한 뱀장어 유생은 부화 후 60일 동안 생존하였다. 각 먹이의 단백질 함량은 비슷하였지만, D-type 먹이의 n-3 HUFA 농도는 다른 type의 n-3 HUFA 농도보다 약 2배 높았다.

• 한국해양생명과학회지
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• 제7권2호
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• pp.171-179
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• 2022

본 연구는 양식산 참돔과 넙치를 Cochlodinium polykrikoides 적조에 노출시켜 노출 시간에 따른 생존율, 호흡수, 혈중 스트레스 지표 및 조직학적 변화를 비교 조사하였다. 대조구는 자연해수를 사용하였고, 실험구는 C. polykrikoides 밀도를 5,500±200 cells/ml로 설정하였다. 그 결과, 참돔은 적조 노출 1시간 이내, 넙치는 적조 노출 5시간 이내 전량 폐사하였다. 생리학적 반응을 분석한 결과, 참돔은 적조 노출 후 혈중 Glucose 농도가 감소하였으며, 혈중 GOT 및 GPT농도는 증가하였고, 혈중 SOD 농도는 감소하고, CAT 및 GPx 농도는 증가하는 경향을 보였다. 넙치는 적조 노출 후 혈중 Cortisol 및 GOT, GPT 농도가 증가하였고, 혈중 Glucose 농도는 적조 노출 1시간째 증가한 이후 감소하였으며, 혈중 SOD, CAT, GPx 농도는 노출 1시간째 감소한 이후 증가하였다. 조직학적 분석 결과, 참돔과 넙치의 아가미에 구조적인 손상이 발생하였다. 결론적으로 5,500 cells/ml 밀도의 C. polykrikoides 적조 노출은 양식산 참돔과 넙치에게 산화적 스트레스로 작용하여 체내 항산화 방어 기작을 활성화하고, 간과 아가미의 손상을 발생시키는 것으로 나타났다.