• 수산해양기술연구
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• 제28권4호
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• pp.337-346
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• 1992

어군탐지기를 이용하여 어군의 분포와 그 행동생태를 계측하기 위한 연구의 일환으로 어군의 연직적인 일주회유이동 및 초음파산란강도의 변동특성을 검토하고, 또한 수온의 연직구조와 어군의 연직분포특성과의 관계, 선박의 항주상태에 따른 어군의 행동반응 등을 현장실험을 통하여 검토, 고찰한 결과를 요약하면 다음과 같다. (1) 어군의 공간분포특성은 수온의 연직구조와 밀접한 관계가 있음을 알 수 있었다. (2) 동중국해 중앙부에서 일출 직전까지 수온약층 바로 아래쪽에 군집하고 있던 칼오징어와 전갱이 어군이 일출과 더불어 해저를 향해 급속히 하강하는 일주회유이동이 관찰되었고, 그 하강속도는 0.24m/min이었다. (3) 수온약층이 탁월했던 제주도 서방해역과 대만 북부해역을 대상으로 어군의 연직분포특성과 수온의 연직구조와를 상호 비교 분석한 결과, 표층과 저층의 수온차가 크고, 또 중층에 뚜렷한 수온약층이 형성되어 있는 경우, 전갱이와 칼오징어군은 야간에 수온약층의 바로 아래쪽에 농밀하게 군집하는 특성을 나타내고, 또 표층과 저층의 수온차가 적은 경우에 있어서는 표층까지 완전히 부상하여 군집하는 경향을 나타내었다. (4) 선박을 정선시킬 때, 선저 직하에 분포하는 어족생물이 급히 연직적으로 하향 이동하는 도피행동을 나타내었다. 그러나, 그 후 시간이 경과함에 따라서 다시 원래의 유영층으로 상향이동하는 행동패턴을 나타내었다. 한편, 수온약층을 경계로 하여 상층과 하층에 분포하는 어족생물의 행동패턴에도 차이가 있었는데, 수온약층 아래쪽에 있어서는 어군이 현저한 도피행동을 나타내었지만, 그 위쪽에 있어서는 그러한 징후가 관찰되지 않았다. 이와 같은 현상은 수온약층 아래쪽에는 유영성이 강한 어족생물이, 그 위쪽에는 유영성이 약한 어족생물이 군집하고 있었기 때문이라고 판단된다. 당시 이 해역에서 행한 저층 트롤의 주요 어획물은 물메기, 살오징어, 삼치 등이었다.

• 한국어류학회지
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• 제11권1호
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• pp.72-85
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• 1999

전선역 주변해역의 자치어 종 조성에 관한 조사가 대한해협을 대상으로 1993년 8월에 실시되었다. 북위 $35{\sim}36^{\circ}$의 대륙사면 주변해역에 전선이 형성되어있었다. 총 125 종류의 자치어가 출현하였다. 우점종은 멸치와 앨퉁이였으며 두 종의 출현량 비율은 각각 84.3%와 7.7%였다. 출현 빈도가 높은 종은 망둑어과, 돛양태과 그리고 자리돔과 둥이다. 위의 5종은 크게 모든 조사해역에서 출현하는 멸치와 돛양태과, 전선역을 경계로하여 수온이 높은 전선역의 남부해역에 주로 출현하는 망둑어과와 자리돔과 그리고 전선역을 포함한 전선역의 북부해역에 주로 출현하는 앨퉁이로 크게 구분되었다. 본 연구해역에서 자치어의 종 조성과 지리적인 분포는 어류의 종별 산란생태 뿐만 아니라 대마난류수와 동해고유수의 접촉으로 형성된 전선의 지리적인 분포와 구조등과 같은 물리적인 영향을 받는 것으로 판단된다.

• 한국어류학회지
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• 제25권4호
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• pp.227-233
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• 2013

태안반도 모항항의 암반조간대 조수웅덩이에서 2010년 1월부터 12월까지 매월 어류를 채집하여 고도에 따른 종조성분포를 분석하였다. 조사 기간 동안 채집된 어류는 3목 8과 14속 16종이었으며, 이 가운데 망둑어과의 점망둑(Chaenogobius annularis)이 34.6%로 우점하였고, 아우점종으로는 그물베도라치(Chaenogobius annularis)가 22.0%, 조피볼락 (Chaenogobius annularis)이 6.9%, 두줄망둑 (Chaenogobius annularis)이 6.8%순이었다. 그물베도라치는 고도에 관계없이 주거종으로 출현하였으며, 점망둑은 상부조간대에서 가장 우점하였고, 모든 조사 시기에 채집되었다. 주거종의 개체수는 일시주거종과 기회방문종보다 높았으며, 생체량은 주거종이 61.4%로 가장 높았으며, 일시주거종이 14.2%, 기회방문종이 24.4%였다.

• 생태와환경
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• 제46권3호
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• pp.367-379
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• 2013

꺽저기 Coreoperca kawamebari는 탐진강 및 인접 하천에 제한적으로 분포하는 반면, 꺽지 C. herzi는 전국의 여러 하천에 분포한다. 두 종의 공서 수역에 대해서 지금까지 보고되지 않았으나, 본 연구에서 섬진강의 지류인 보성강과 영산강의 지류인 지석천에서 두 종의 공서 수역을 확인하였다. 꺽저기와 꺽지의 공서 수역 내에서 하천 환경의 차이에 따른 두 종의 분포 양상과 어류 군집의 특성을 확인하기 위하여 2011년 9월부터 2012년 10월까지 보성강 상류 수역에서 환경 요인과 어류 군집을 조사하였다. 순위 수도 분포 분석에 의하면, 서식지 환경이 다양할수록 꺽저기와 꺽지의 출현 비율이 비슷할 뿐만 아니라 어류 군집의 종다양성이 높았다. 정준대응분석 결과에서 꺽저기는 정체 수역에 서식하는 반면, 꺽지는 하상이 호박돌으로 이루어지고 유속이 빠른 환경에 서식하는 것으로 나타났다. 따라서 본 연구에서는 꺽저기와 꺽지의 서식지 환경이 상이하다는 것을 확인하였고, 하천의 서식지 환경이 단순하면 꺽저기나 꺽지 중 한 종만 출현하고 어류 군집의 종 다양성이 감소하였으며 서식지 환경이 다양하면 이들 두 종이 공존할 수 있고 종 다양성이 증가하는 것으로 파악되었다.

• 수산해양기술연구
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• 제30권4호
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• pp.239-250
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• 1994

The vertical distribution and activity patterns of fishes during the evening and morning transitions between day and night were studied acoustically and by bottom trawling in November 1990-1992 in thermally stratified waters of the East China Sea. The acoustic data were collected from six stations with a scientific echo-sounder operating at two frequencies of 25 and 100kHz, and the echograms were used to determine the vertical distributions of fish. Biological sampling was accomplished by bottom trawling to identify fish species recorded on the echograms, and the species and length compositions were determined. At each station, vertical profiles of water temperature, salinity and dissolved oxygen were taken with a CTD system and were related to the diel movements and the depth distributions of fish. During the day most fish were within several meters above bottom, but began to migrate upwards just before sunset, and during the night they were dispersed in midwater. Prior to sunrise with a thermocline present, one group of the fish aggregation occurred in dense schools slightly above the thermocline, while the other group occurred with the numerous single fish-traces bellow it. These groups of aggregations rapidly began to migrate toward the bottom across the thermocline from about 40 min before sunrise. Trawl hauls in the bottom strata below the thermocline with the characteristic single fish traces yieled invariably catches dominated by snailfish and fishing frog with minor quantities of other species in all stations. Hence, the results indicate that snailfish and fishing frog were the dominated scatterers in the depth strata below the thermocline, and the single-fish recordings were mainly snailfish. The fish species such as anchovy and juvenile mackerel in bottom trawl catches is poorly represented in relation to the mesh selectivity of the trawl net, but their occurrence suggest that the fish-school recording above the thermocline were due to these species which migrated vertically across the thermocline, with a temperature gradient of about 8$^{\circ}C$, from the water layers near the bottom at night. Accordingly, we conclude that the vertical distribution and activity patterns of snailfish were strongly temperature dependent and in the termally stratified waters, the upper limit to diel activity was closely linked to the position of the thermocline.

• 한국수산과학회지
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• 제44권1호
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• pp.8-17
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• 2011

To identify and examine the distribution of proteolytic inhibitory activity in crude extracts from fish eggs, and to determine the applicability of these protease inhibitors as anti-degradation agents in surimi-based products and fish meat, we compared the inhibitory activities of various extracts from fish eggs to those of commercial proteases, such as trypsin and papain. We used the optimal conditions for the screening of trypsin activity: 30 ug/uL of 0.1% trypsin and 0.6 mM Na-benzoyl-L-arginine-p-nitroanilide (BAPNA) with a pH of 8.0 at $40^{\circ}C$ for 60 min. The activities of papain and four commercial proteases were investigated after mixing with 100 ug/uL enzymes and 0.3% casein with a pH of 8.0 at $40^{\circ}C$ for 60 min. We performed a screening assay to detect the inhibitory activity (%) of crude extracts from eight species of fish eggs against the target proteases trypsin and papain. The assay revealed a wide distribution of trypsin and papain inhibitors in fish eggs. The specific inhibitory activities (11.6.28.6 U/mg) of crude extracts from fish eggs against trypsin and BAPNA substrate were higher than that (0.64 U/mg) of egg whites, used as a commercial inhibitor. The inhibitory activities of crude extracts from fish eggs against trypsin, and of egg whites against casein substrate (1.94.4.51 U/mg), were higher than those of papain (0.24.1.57 U/mg) and commercial protease (0.04.0.32 U/mg). The extracts from fish eggs were rich in protease inhibitors that exhibited strong inhibitory activity against trypsin, a serine protease, and papain, a cysteine protease.

• 한국수산과학회지
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• 제46권6호
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• pp.973-976
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• 2013

We observed the vertical distribution and feeding ecology of the Mirror dory, Zenopsis nebulosa, in the Southern Sea of Korea from 2009 to 2013 using an otter trawl. The total length of captured individuals ranged from 11 to 48 cm. Individuals captured at greater depths were significantly larger than those from shallower sites. Fish abundance was significantly related to depth and temperature. We found that 89% of the total catch was obtained at depths between 80 and 140 meters. Prey organisms, including fish, crustaceans, and cephalopods, were found in Z. nebulosa stomachs. Fishes were the main prey items for all size groups. Cephalopods were consumed by individuals > 25 cm in length. Our findings suggested that the vertical distribution of Z. nebulosa varied with depth and temperature, and that the fish are carnivores.

• 수산경영론집
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• 제43권3호
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• pp.89-106
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• 2012

This study estimated the size of ornamental fish market as the basis survey for the development of the ornamental fish industry in Korea. It presents improvement projects agendas for the development of the Korean ornamental fish industry by investigating the challenges of the ornamental fish industry and consumer awareness. First, looking at the size of the ornamental fish market, calculated on the basis of survey results, the size of ornamental fish market is analysed as 231.8 billion won. The actual ornamental fish market is presumed to be much larger than this considering unclear gross sales from e-commerce and group sales, goods excluded from the ornamental fish export, expensive ornamental fish transaction from smuggling are missing. Ornamental fish industry and consumer awareness survey results can be described as follows: First, revenue structure of the ornamental fish market depends on a handful of expensive purchasing group rather than on low-cost consumption group. Second, many members of the ornamental fish producers, wholesalers, road shops are small-scale. Third, the sale of aquarium fish and aquarium fish related supplies in road shop have different market structures. Fourth, ornamental fish consumption is in the ongoing recession. Fifth, ornamental fish industry hopes for expansion of distribution and Research & Development. Sixth, satisfaction of ornamental fish consumers is generally low. As described above, ornamental fish industry in Korea are vulnerable in the market structure and industry is small and the consumer's satisfaction degree is staying in the 'normal' level. If current state will continue, future consumption can be reduced. It is necessary to increase the competitiveness by using various method including reorganization of the structure of the ornamental fish industry even though it is hard to reach conclusion only with the results of the survey.

• 한국수산과학회지
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• 제37권3호
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• pp.249-254
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• 2004

The hydro-acoustic method is widely used for estimating biomass and distribution of fisheries resources along the coast and in the ocean. High costs and time are necessary to construct systems for this method and to initially educate specialists. It has been used in fisheries of advanced nations like Japan and Norway, because it is more efficient than other methods. In order to research the behavior of fish around an artificial reef using an echo sounder, volume backscattering strength (SV) and fish per cubic meter (FPCM) of darkbanded rockfish around the model artificial reef in a water tank were measured. Moreover, behavior of fish was observed in an adjacent artificial reef, which was constructed at Tongyeong marine ranching area. Following that, an acoustics survey was conducted at Mirukdo around the Tongyeong marine ranching area, in order to understand the spatial distribution and strength of fisheries resources. Very high patches of fish were found in a wide area around the artificial reef. It is thought that an approaching fish school around the artificial reef can be measured accurately by using an echo sounder of high resolution. Moreover, use of other monitoring methods like of diving or ROV simultaneous with an echo sounder is required in order to grasp the species and ecology of fish inhabiting the area around the artificial reef.

• Fisheries and Aquatic Sciences
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• 제23권4호
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• pp.14.1-14.14
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• 2020

We performed field measurements of the behavioral changes in cultured chub mackerel (Scomber japonicus) caused by tide-induced changes in the shapes of their small-sized tetragonal fish cages. The field measurements were conducted in two separate periods: neap tide, a period in which the shape of the fish cages was stable; and spring tide, a period in which the fish cages are significantly deformed, which was expected to have significant influences on fish behavior. In the spring tide, the cages were deformed greatly by the moving water, with different water velocities affecting the cages to different degrees; the volume loss was estimated at 4.9% and 7.3% for v = 0.114 m/s and v = 0.221 m/s, respectively. The fish exhibited significantly different behaviors between the neap tide and spring tide. During the neap tide, the fish remained in the lower part of the cage, but during the spring tide they made frequent upward and downward movements, and their horizontal distribution changed significantly due to the changes in the shape of the cage. The cage deformation during the spring tide greatly influenced the swimming behavior of fish.