• 환경영향평가
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• 제20권6호
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• pp.845-856
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• 2011

In order to establish fundamental data for stream restoration and environmental flow, we investigated inhabitation and species diversity of fish to substrate size in the typical streams of Geum River Basin. Field monitoring including fish sampling was conducted from October 2007 to October 2009. Substrate size was determined according to six different : silt (Si), sand (Sa), fine gravel (Fg), coarse gravel (Cg), cobbles (Co) and boulders (Bo). A total number of fish caught in the 18 sites was 7,649 representing 10 families 50 species, and Si, Sa, Fg, Cg, Co and Bo stations occupied 30, 29, 38, 30, 27 and 17 species, respectively. The most frequently found species in number was pale chum (Zacco platypus, 29.7%, n=2,275) followed by Z. koreanus (22.5%, n=1,720) in total stations. Biological diversity with increase of substrate size from the dominance of part species showed higher values as dominance index, lower and diversity, richness and evenness index. Index of biological integrity (IBI) and qualitative habitat evaluation index (QHEI) scores decreased with increase of substrate size. Therefore, it is necessary to make an effort on stream rehabilitation with evaluation of physical habitat condition by indicator species in order to maintain biodiversity and perform ecological restoration.

• Fisheries and Aquatic Sciences
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• 제11권1호
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• pp.61-69
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• 2008

Using empirical data of fish performance and physiological limits as well as physical stimuli and environmental data, a cod-end selectivity model based on a chaotic behavior model using the psycho-hydraulic wheel and neural-network approach was established to predict fish escape or herding responses in trawl and cod-end designs. Fish responses in the cod-end were categorized as escape or herding reactions based on their relative positions and reactions to the net wall. Fish movements were regulated by three factors: escape time, a visual looming effect, and an index of body girth-mesh size. The model was applied to haddock in a North Sea bottom trawl including frequencies of movement components, swimming speed, angular velocity, distance to net wall, and the caught-fish ratio; simulation results were similar to field observations. The ratio of retained fish in the cod-end was limited to 37-95% by optomotor coefficient values of 0.3-1.0 and to 13-67% by looming coefficient values of 0.1-1.0. The selectivity curves generated by this model were sensitive to changes in mesh size, towing speed, mesh type, and mesh shape.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.97-100
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• 2008

Various flyers in nature have attracted great interests with a recent need for developing versatile and small-size flight vehicles. In the present study, we focus on the flying fish which has been observed to glide a long distance just above a seawater surface. Since previous studies have depended on the field observation or measurement of the physical parameters only, quantitative data of the flying fish flight has not been provided so far. Therefore, we evaluate the wing performance of the flying fish in gliding flight by directly measuring the lift, drag and pitching moment on real flying fish models (Cypselurus hiraii) in a wind tunnel. In addition, we investigate the roles of wing morphology like the enlarged pectoral and pelvic fins, and lateral dihedral angle of pectoral fins. With both the pectoral and pelvic fins spread, the lift-to-drag ratio is larger and the longitudinal static stability is enhanced than those with the pelvic fins folded. From the glide polar, we find that the wing performance of flying fish is equivalent to those of medium-size birds like the petrel, hawk and wood duck. Finally, we examine the effect of water surface underneath the flying fish and find that the water surface reduces the drag and increases the lift-to-drag ratio.

• 한국수산과학회지
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• 제37권6호
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• pp.505-510
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• 2004

The feeding habits of brown barracuda (Sphyraena pinguis) were analyzed using the stomach contents of monthly samples collected from coastal waters of Gadeok-do, Korea from January to December, 1998. Brown barracuda occurred mainly from summer to autumn in the study area, and ranged from 15 to 35 cm in standard length. Brown barracuda was a piscivorous fish which, mainly consumed teleost fish such as anchovy (Engranlis japonicus) and chefoo thryssa (Thfssa kammalensis). Its diet also included small quantities of shrimp and cephalopods. Although smaller fishes (<25 cm SL) consumed shrimp and cephalopods as well as fish, larger fishes (>30 cm SL) consumed exclusively teleost fish. The prey size increased with increase of fish size.

• 한국산학기술학회논문지
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• 제17권9호
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• pp.265-278
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• 2016

본 연구에서는 국내에서 서식하는 외래어종인 배스와 블루길을 대상으로 소상능력 실험을 수행하였다. 실험은 대상 어류의 크기에 따라 4개 그룹으로 구분한 후 각 그룹별 4단계 유속에 대한 실험을 진행하였다. 분석방법은 유속에 따라 기준선을 통과하는 개체 수를 영상촬영을 이용해 분석하였으며 어류의 유영 및 소상 가능정도를 육안으로 관찰하였다. 또한 고유속 급류로 인해 5분 내 하류로 내려오면 기준선 통과 개체 수에서 제외하였으며 유속은 좌안, 우안, 중앙에서 측정하여 평균값을 사용하였다. 실험 결과 어종 및 개체 크기에 상관없이 유속이 빠를수록 소상하는 외래어종은 감소하는 것으로 나타났다. 어종별 비교 결과 배스의 소상능력이 블루길보다 높게 나타났으나 개체 크기를 고려하면 차이는 크지 않는 것으로 판단된다. 소상 후 급류로 인해 하류로 밀려 내려오는 경우를 제외하고 실험오차를 고려하면 외래어종이 소상 가능한 한계속도는 1.11 m/s 이상인 것으로 판단된다. 실험 결과는 고유속 흐름을 이용한 어류 차단과 외래어종의 관리를 위한 기초자료로 활용이 가능하며 향후 고유속에서 기준선을 통과하는 어류가 돌발속도에 의한 것인지 순항속도에 의한 것인지 판단하기 위해서는 지속적인 실험과 검증 및 모니터링이 필요하다. 또한 외력에 의한 반응 및 유량에 의한 압력 차이 등을 고려한 어류의 반응검토도 필요할 것으로 판단된다.

• 수산해양기술연구
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• 제33권2호
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• pp.109-117
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• 1997

우리나라 남해안의 거제도 도장포와 남해군 미조면에 설치되어 있는 수심 20m해역의 중형 정치망어구를 대상으로 길그물 및 통그물의 어군수도기능과 원통그물의 어군체유효과 등을 현장 실험을 통해 검토, 분석하였다. 어류에 Tag를 부착하고 통그물의 각부와 길그물의 주변에 방류 시켜 다음 양망과정에서 재포하였으며, 본 실험을 통해 얻은 결과를 요약해 보면, 다음과 같다. 1. 정치망의 헛통에서 방류하여 양쪽 원통 안으로 들어가 재포된 입망률은 소형 고등어가 20.3%, 소형 전갱이는 16.2%, 감성돔은 10.3%, 꼬치고기는 19.1%, 학공치는 16.3%, 전어는 20.0%였으며, 전체 방류미수 667마리 중에서 115마리로 17.2%였다. 2. 양쪽 원통에서 방류하여 다시 그 원통그물내에서 재포된 잔류율은 소형 고등어가 21.7%, 소형 전갱이는 21.5% 감성돔은 6.7%, 꼬치고기는 17.8% 학공치는 16.8% 전어는 19.1%를 나타냈으며, 전체 방류이수 1,513마리 중에서 284마리로 18.8%였다. 그리고 81.2%는 원통그물로부터 빠져나갔다. 3. 창문으로부터 25m거리의 길그물 양측 지점에서 방류하여 헛통으로 들어간 비율, 즉 길그물의 수도율은 소형 고등어가 58.9%, 소형 전갱이는 74.6%, 감성돔은 38.0%, 꼬치고기는 54.7% 학꽁치는 58.6%, 전어는 54.5%였으며, 총방류미수 1,086마리 중에서 627.4마리로 평균 57.8%를 나타내었다. 따라서 소형 고등어, 소형 전갱이, 꼬치고기, 학공치 및 전어는 길그물의 차단수도교과가 크게 작용하는 어종으로 나타났다. 4. 꼬치고기, 학공치, 전어는 조상측의 원통그물에 많이 입망되었고, 소형 전갱이와 감성돔은 조하측 원통그물에서 많이 입망되었다. 5. 소형 고등어와 소형 전갱이는 조하측 원통그물에서 잔류율이 높았고, 감성돔, 꼬치고기 및 학공치는 조상측 원통그물에서 잔류율이 높았다.

• 한국수산과학회지
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• 제44권2호
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• pp.173-178
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• 2011

The species and size compositions of fishes in the coastal waters off Taean were determined using samples collected with a two-sided fyke net in 2008. A total of 22 species, 2,371 individuals and 1,351 kg of fish were collected during the study. Of the fish collected, semi-benthic fishes such as Sebastes schlegelii, Mugil cephalus and Chelon haematocheilus were the most abundant (77.5% and 76.4% for total number of individuals and biomass, respectively). Benthic fishes such as Pleuronectus yokohamae and Paralichthys olivaceus were collected in almost all seasons but were low in abundance (5.3% and 4.1% for total number of individuals and biomass, respectively). Seasonal migrants were plentiful; specifically, Seriola quinqueradiata was abundant in November while Konosirus punctaus was common in July. Seasonal migrants of small-sized fish have been known to be abundant in the coastal water of western Korea including the study area, but few fish less than 100 mm were collected due to the large mesh size (30 mm) of the net used.

• Ocean and Polar Research
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• 제36권2호
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• pp.199-208
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• 2014

Copepods are a major food source for marine fish larvae in nature. Many studies on copepods culture have been conducted to develop a new live food for the seedling production of marine fish larvae. But fish farmers still depend on rotifer and Artemia nauplii. This study was carried out to find suitable copepods as live food for the larvae in hatchery. Eight species of copepods (1 calanoid, 2 cyclpoid, 5 harpacticoid) that were fed Isochrysis galbana were examined in terms of the size of nauplii, fecundity, amino acids, and fatty acids contents. These species were divided into small (nauplii length 46-86 ${\mu}m$) and large (nauplii length 120-188 ${\mu}m$) size group. Nitokra spinipes in the small group and Tigriopus japonicus in the large group showed the highest fecundity with 151.1 and 139.6 nauplii production per gravid female, respectively. With regard to nutrients, essential amino acids were the highest with 21.2% in cyclopoid Paracyclopina nana in the small group and n-3 HUFA were the highest in calanoid Pseudodiaptomus inopinus (8.5 ${\mu}g/mg$) in the large group and P. nana (8.8 ${\mu}g/mg$). In terms of the size, fecundity, and nutritional value of copepods examined in this study, N. spinipes and P. nana seem to be suitable copepod species to develop as a new live food for small mouth fish larvae.

• Environmental Engineering Research
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• 제13권3호
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• pp.147-154
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• 2008

The purpose of this study was, as a preliminary step for understanding the whole aspects of the impacts of a weir on the ecosystems in upper and lower streams, to find out the impacts of the weirs with and without a fish-way. A survey on the aquatic ecosystem of upper and lower streams of weirs in Ham-an Stream was carried out from June to October, 2006. Results of the investigation showed that some meaningful effects on the ecosystems had occurred by the weirs. The fish fauna in upper stream of the weir with a fish-way appeared to include 3 families, 8 species, and 184 individuals, while that in the lower stream of the weir appeared to include 5 families, 14 species, and 664 individuals. The fish fauna in the upper stream of the weir without a fish-way appeared to include 3 families, 9 species, 107 individuals, while that in the lower stream of the weir appeared to include 9 families, 19 species, 520 individuals, disclosing that, no matter with or without a fish-way, fish fauna species diversity and size of population were more abundant and bigger in the lower stream than in the upper stream, but that difference of fish fauna species diversities between upper and lower streams of the weirs appeared to be bigger for the weir with a fish-way than for the weir without a fish-way. Benthos species diversity and size of population were found to be more abundant and bigger in lower stream than in upper stream, and in wet season than in dry season.

• 한국전자통신학회논문지
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• 제18권1호
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• pp.127-142
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• 2023

양식장에서 양식어의 생육 정보인 크기 및 무게의 관리는 가장 기본적인 목표이다. 본 연구에서는 육상 양식장에서 입식 또는 분조 시점부터 출하 시점까지를 epoch로 정의하고, 총 3 epoch에 대하여 생육데이터를 시계열 관점에서 분석하고자 한다. 양식장에서 시간 흐름에 따라 발생하는 양식어의 크기 및 무게 등의 생육 정보를 수질 환경 정보, 급이 정보와 비교 분석하고, 분석 결과를 이용하여 모델을 제시한다. 본 연구에서는 현장에서 획득된 데이터를 이용하여 크기 및 무게에 대하여 Box-Jenkins 방법을 이용하여 선형, 지수, 로그 회귀분석 모델을 제시한다.