• 한국수산과학회지
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• 제50권4호
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• pp.429-436
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• 2017

The seasonal and interannual variations in fish assemblages in the coastal waters off Gijang were examined with an otter trawl from 2015 to 2016. A total of 59 fish species was collected during the study period. The dominant species were Caelorinchus multispinulosus, Clupea pallasii pallasii and Chelidonichthys spinosus. Seasonal changes in fish assemblages appeared to be distinct in the study area. The fish assemblages in summer and autumn were clearly distinguishable from those in other seasons, and the largest numbers of species and individuals were captured in winter and summer, respectively. Because fish assemblages are closely related to changes in water temperature, long-term changes in water temperature can have a significant impact on the productivity of offshore fisheries by changing fish species composition, habitat migration, and growth rate of fish.

• 수산해양교육연구
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• 제16권1호
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• pp.124-141
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• 2004

This study focuses on the off-shore trawl fishery, specifically on its restructuring and new regulations governing its operation since the 1990s. This fishery has an important role in terms of fishing capacity and production amount and is dependent on close diplomatic relations with adjacent fishing countries. The off-shore trawl fishery has been shrinking since the 1990s. In addition to a decrease in stock and an increase in imports, there are vessel buyback programs and a decrease in fishing grounds related to a tri-lateral agreement among Korea, China and Japan which have sped up the shrinking of the fishery. In this processing, costs exceed the increase of revenue. Excess investments in fishing gear and salary for crews have lowered profits in this fishery. Considering the above, the off-shore otter trawl fishery should stop increases in production and restructure the fishery by coordinating fishing gear restrictions and fishing areas, and down-sizing management capacity.

• 환경영향평가
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• 제29권4호
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• pp.298-306
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• 2020

본 연구는 새만금호 일대 수달의 서식지적합도 분석과 공간변수(수역, 습지, 농경지, 시가지, 도로 등)와의 상관성이 수달 서식에 미치는 영향을 파악하기 위하여 이루어졌다. 서식지적합성 분석결과, 전체 1097개 격자 중 1등급과 2등급이 380개 격자로 전체 34.6%로 확인되었고 4등급과 5등급이 413개 격자로 전체 37.7%로 비교적 낮은 것으로 확인되었다. 새만금 일대의 공간변수 별 수달 서식흔적과의 거리를 비교분석한 결과, 도로와 시가지는 거리가 멀수록 수달의 흔적이 확인되는 것으로 확인되었고 수역과의 거리는 가까울수록 흔적이 확인되었다. 새만금호 내부 공사로 인한 영향은 있으나 수역과 도로의 이격거리를 보면 시가지와 도로에서 이격거리가 근접한 지역과 가장 먼 지역과의 흔적차이가 2배에서 6배 이상 나타나는 것으로 확인되었다. 이는 수달의 서식지 복원시 위협요인으로 작용하는 도로와 시가지는 최소한 500(m) 이상 이격거리가 필요하다고 판단된다.

• 수산해양기술연구
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• 제56권3호
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• pp.213-222
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• 2020

Species composition and seasonal variations of fish in the Five West Sea Islands in Korea, were investigated by using otter trawls and bongo nets from 2014 to 2015. During the surveyed period using an otter trawl, a total of 53 species, 147,253 ind./㎢ and 2,721,296 g/㎢ of fish were collected by otter trawls. The individual dominant species were Chaeturichthys stigmatias (30.3%), Coilia nasus (18.2%), Engraulis japonicus (12.3%), and Setipinna tenuifilis (12.2%). Moreover, the biomass dominant species in biomass were Liparis tanakae (21.3%), Beringraja pulchra (18.5%), Engraulis japonicus (8.3%) and Okamejei kenojei (8.1%). Eggs by bongo nets included 1,748 ind./1,000 ㎥ of Engraulis japonicus and 64,691 ind./1,000 ㎥ of unidentified species. A total of 15 species and 2,015 ind./1,000 ㎥ of fish larvae were collected, and the dominant species were Johnius belengerii and Pholis fangi.

• 수산해양기술연구
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• 제34권3호
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• pp.294-301
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• 1998

Towing performance of a midwater trawl system was examined aboard the training ship KAYA(2900ps) at the East Sea using the midwater trawl gear that had been designed and manufactured in accordance with the vessel. In this experiment, the trawl system data, the towing speed, the length and tension of the warp, net mouth height, and the depth of otter boards and net were measured and analyzed. The results are as follows: 1. In case of heaving in the warp with constant towing speed, the tension was suddenly increased and then again was reduced and after returned to the original steady state tension. At this time, net height was reduced a bit by ascension of ground rope, but returned to it’s original value. In the case where the warp was paid out, the tension was suddenly decreased and after increased and then returned to the tension of the original state, and the net height was greatly increased instantly by the sinking of the ground rope and then returned to the steady state 2. In the case of increased towing speed mm constant warp length, the tension was increased, and reducing the net height, the gear depth was decreased. On the other hand, in the case where towing speed was reduced, the tension was reduced and the gear depth and net height was increased. 3. Otter boards show a swing motion in the scope of 5~ 10m continuously. Otter boards responded to the state change of the trawl system at first, and then the motion of the net appeared. 4. The depth of net center was about 20m deeper than that of the otter boards, it shows about 0.4 times the warp length at the 4knots towing speed.

• 수산해양기술연구
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• 제43권4호
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• pp.251-260
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• 2007

A species composition and population structure of fish, collected 16 times by bottom otter trawl in the coast of Geumo Island, from February 2002 to November 2005, was investigated. The fish species caught by bottom otter trawl from year 2002 to 2005 was entirely 72 species, 41 classes, and 12 orders, and the number of appearance and biomass was 5,999 individuals and 287,902.1g, respectively, being of the Perciformes(31 species and 19 classes; 43.1% in total number of species appeared) as a dominant species. 638 individuals of Leiognathus nuchalis which was 10.6% in total fish were appeared and 465 individuals of Konosirus punctatus(7.8%), 449 individuals of Engraulis japonicus(7.8%). biomass of Sebastes schlegeli was 33,258.7g as a dominant species(11.6% in total fish appeared) and 18,821.1g of Liparis agassizii(6.5%), 16,708.0g of Konosirus punctatus(5.8%). The diversity index of species per months of the collected by a small otter trawl in coastal water of Geumodo from year 2002 to 2005 was 2.860-3.639 and the evenness index was 0.825-0.887 in case of dominance index was 0.224-0.268 against the evenness index. The similarity of community structure per yearly was very high because of the relative difference(0.006), which was the least in 2004 and 2005.

• 한국수산과학회지
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• 제20권6호
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• pp.484-488
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• 1987

단순만곡형과 슈퍼-V형 모형 전개판의 뒷전 쪽에 각각 flap을 부착하고, 회류수조에서 진행각도와 유속에 따른 항력과 전개력을 측정하여 유체역학적인 전개성능을 분석한 결과는 다음과 같다. 1. flap을 부착한 모형 전개판의 전개력계수 $C_L$은 flap각도 $30^{\circ}$와 $50^{\circ}$일 때 단순만곡형은 최대유효진행각도 $\alpha_{max}=25^{\circ}$ 1.75 정도이었고, 슈퍼-V형은 $\alpha_{max}=20^{\circ}$에서 1.80정도로 flap을 부착하지 않은 경우보다 $20\~30\%$ 정도 $C_L$이 증가하였다. 2. 항력계수 $C_D$는 $\alpha_{max}$ 일 때 flap각도에 관계없이 단순만곡형과 슈퍼-V형 모두가 0.5 정도로 거의 차이가 없었고, flap을 부착하지 않은 경우보다는 약간 $C_D$가 증가하였다. 3. 유체효율 $C_L/C_D$는 flap각도 $30^{\circ}$일 경우가 $50^{\circ}$일 경우보다 약간 높았으나, $\alpha_{max}$일 때는 거의 비슷하였으며, flap를 부착하지 않은 경우보다는 악간 높은 경향을 보였다.

• 한국수산과학회지
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• 제24권4호
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• pp.248-254
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• 1991

1990년 8월 아산만에서 otter trawl을 이용하여 저어류를 채집하여 정점을 대표할 수 있는 저어류 군집 자료수집 방법을 추정하였다. 조사기간 중 총 17종, 957개체, 21,840g의 어류가 채집되었으며, 참서대 (Cynoglossus joyneri), 곤어리 (Thrissa koreana), 쥐노래미 (Hexagrammos otakii)와 민태 (Johnius belengerii)가 출현 빈도도 높고 개체수와 생체량에서 우점하였다. 주야 10회 반복 채집결과 종조성은 주야에 따라 유의한 차이를 보이지 않았으나, otter trawl 20분 예인의 개체수 자료는 우점종의 경우는 평균에 대하여 $2.2-385.1\%$, 전어종은 $52.2-162.0\%$의 넓은 변이를 보였다 채집면적을 늘려 갔을 때 누적종수는 예인 4회 자료 누적 이후에는 증가가 둔화되었고 종다양성지수는 3회 이후 거의 점관선에 도달하였다. 개체수의 평균에 대한 분산은 자료를 누적시켰을 때 감소하여 4회 이후에는 자료가 Poisson 분포 양상을 보였다. Otter trawl을 이용하여 아산만 저어류를 채집할 때 20분 예인 4회 이상의 자료를 합하면 정성, 정량적으로 한 조사정점을 대표할 수 있는 것으로 판단된다.

• 한국습지학회지
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• 제17권4호
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• pp.402-406
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• 2015

본 연구는 강원도 홍천강 유역에 서식하는 수달이 선호하는 지역을 파악하기 위해 수달의 배설물을 이용하여 하천환경의 현황을 분석하였다. 수달의 배설물은 영역표시 및 서식지이용에 대한 근거로 활용되기 때문이며, 이를 통한 하천의 주요 서식지를 확인할 수 있다. 내촌천과 군업천의 수달은 2009-2011년 총 8회 기간에 478개의 서식흔적이 발견되는 지점을 중심으로 조사되었으며 서식지 이용현황을 파악하기 위한 분산지수를 활용하였다. 두 하천 모두 계절적 이용의 변화가 나타났으며, 분산지수 값 1은 배설물이 집중되는 것을 의미하며 이는 하천 이용이 임의적이 아닌 것임을 나타내었다. 수달은 하천 주변의 5m 이내의 지역이며, 어류와 잔목이 풍부한 수변지역을 선호하는 것으로 나타났다. 수달의 서식지 이용에 대한 정확한 환경조건을 파악하기 위한 모델의 개발이 시급한 것으로 조사되었다.

• 대한수의학회지
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• 제58권2호
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• pp.107-109
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• 2018

An 8-year-old female Eurasian otter (Lutra lutra) reared in a wetland center, died 2 h after sudden onset of astasia and dyspnea despite medical treatment. Gross examination of internal organs revealed 10 adult filarioid nematodes in the right ventricle of the heart and three between the left and right cerebral hemispheres. All nematodes were identified as Dirofilaria immitis by direct microscopy and polymerase chain reaction assay. Histopathological observation revealed multifocal hemorrhage in the cerebral subarachnoid space and focal necrosis with hemorrhage in the cerebellar parenchyma. Although rare, veterinarians should consider cerebral dirofilariasis as a differential diagnosis in unexplained neurological cases.