• 제목/요약/키워드: Target fishes

검색결과 64건 처리시간 0.024초

얕은 연못에서 수위변동에 따른 담수 어류 피난처 확보를 위한 실험적 접근 (An Experimental Approach to Secure Freshwater Fish Shelter according to the Water Level Fluctuations in a Shallow Pond)

  • 안창혁;주진철;이새로미;오주현;안호상;송호면
    • 대한환경공학회지
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    • 제35권9호
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    • pp.666-674
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    • 2013
  • 담수생태계에서 갈수기가 지속되면 다양한 물리적 장애가 발생한다. 이 시기는 어류의 생태 유지용수가 부족하여, 이동이 일어남에 따라 새로운 피난처 및 서식처가 요구된다. 이러한 문제를 해결하기 위해 본 연구에서는 실증규모의 실험시설을 구축하였으며, 수위변화와 어류 피난처의 관계를 분석하였다. ADP (artificial deep pool)는 본 연구에서 제안된 인공적인 깊은 웅덩이이다. 본 시설을 실증규모의 test-bed 실험구에 적용하여 모니터링 한 결과, 수위변화에 따른 어류 개체수는 실험연못의 수심 0.5 m에서 가장 높게 나타났다. 하지만 ADP에서는 낮은 외부 수위 조건(<0.3 m)에서 단위면적당 어류 개체수가 증가하였고, 실험구의 총 어류 군집을 보존하는데 기여하였다. 또한, ADP 내부의 수온과 DO는 외부보다 낮게 조성되었지만, 어류는 지속적으로 서식하였다. 이 결과와 관련하여, ADP 내부는 WCS, OS, SS, TS 등이 높은 효율적인 정수생태계임을 나타내었다. 더욱이, ADP 내부의 종풍부도는 Acheilognathus koreensis (A. koreensis), Carassius carassius (C. carassius)와 같은 WCS가 높은 비율로 측정되었다. 결국, 수위가 낮게 형성되는 동안 어류는 서식환경의 교란에 의해 수심이 깊은 곳으로 피난하였고, 본 연구 결과를 종합하여 볼 때, ADP는 정수생태계에 적합한 어류 피난 및 서식처로 활용이 가능함을 시사하였다.

제주바다목장해역에서 수중음향과 어획데이터를 활용한 저층 어류의 현존량 추정 (Estimation of demersal fish biomass using hydroacoustic and catch data in the marine ranching area (MRA) of Jeju)

  • 이재봉;오택윤;연인자;김병엽;신현옥;황보규;이경훈;이유원
    • 수산해양기술연구
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    • 제48권2호
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    • pp.128-136
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    • 2012
  • Hybrid surveys using hydroacoustic and fish sampling gears such as trammel net, trap were conducted to investigate total biomass, distribution and dominant fish species of the demersal fishes in the marine ranching area (MRA) of Jeju. Four surveys were carried out in June, August, October and November using 38kHz quantitative echo sounder. Catch data using trammel net and trap were used to calculate biomass and to examine dominant fish species. Fish schools were mainly detected in the waters of 20 meters below and around Chagwido waters. By the result of fishing experiments, fish species living in MRA of Jeju were about 40 species, dominant fish species of a detectable fish such as Family Sparidae and Family Monacanthidae etc. were identified 59.4~68.8% of total biomass. Based on the hydroacoustic data, fish length-weight function and target strength information, mean density of the demersal fish estimated were as follows; 0.88g/$m^2$ on June, 1.12g/$m^2$ on August, 1.35g/$m^2$ on October and 1.18g/$m^2$ on November. An estimated average biomass in MRA of Jeju was founded 20.5 tons in 2007, 20.6 tons in 2008, 23.0 tons in 2009, 25.9 tons in 2010. The results showed that biomass of MRA is getting increased slowly. Therefore the hybrid survey method using hydroacoustic and fish sampling gears is assured an effective biomass survey in the waters of mixed species.

신해양질서 10년후 세계어업자원 이용동향 (The Exploitation of World Fishery Resources for 10 Years under the New Regime in the Sea)

  • 이장욱;허영희
    • 수산경영론집
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    • 제23권1호
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    • pp.43-87
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    • 1992
  • In this paper, state of exploitation of world fishery resources after 10 years under the new regime in the sea, called the era of exclusive economic zone (EEZ) expending up to a 200 nautical miles from coastal line, was reviewed to determine effect from establishing EEZ in the world fishery production and its export/import volume based on the fishery statistics annually published by the Food and Agriculture Organization (FAO) of United Nation. The world total production from marine living resources had a trend showing a waned increase during 1970's when most of coastal states were translated into the reality of EEZ. From mid-1980's onwards, it increased rapidly, reaching about 85 million tons . Such increase in production was basically from the Pacific Ocean, accounting for more than 60% of the world total production. Fishing areas where showed increase in the production after the new regime in the sea were the southwestern Atlantic (FAO area 41) , the eastern Indian (FAO area 57) and the whole fishing areas in the Pacific except the eastern central Pacific (FAO area 77). Increase in the production from distant-water fishing countries came from the regions of the southwest Atlantic (FAO area 41) and the southwest Pacific (FAO area 81) . The production from coastal states was up from the regions of the eastern Indian (FAO area 57) , the northwest and northeast Pacific (FAO areas 61 and 67) and the southeast Pacific (FAO area 87) . It was likely that the exploitation of the fishable stocks was well monitored in the areas of the northwest Atlantic (FAO area 21) , the eastern central Atlantic (FAO area 34) and the northeast Pacific (FAO area 67) through appropriate management measures such as annual harvest level, establishment of total allowable catch etc. The marine fisheries resources that have made contribution to the world production, despite expansion of 200 EEZ by coastal states, were sardinellas, Atlantic cod, blue whiting and squids in the Atlantic Ocean : tunas which mainly include skipjack, yellowfin and bigeye tuna, croakers and pony fishes in the Indian Ocean : and sardine, Chilean pilchard, Alaska pollock, tunas (skipjack and yellowfin tuna) , blue grenadier and blue whiting including anchoveta in the Pacific Ocean. It was identified that both fishery production and its export since introduction of the new regime in the sea were dominated by such coastal states as USA, Canada, Indonesia, Thailand, Mexico, South Africa and Newzealand. But difficulties have been experienced in the European countries including Norway, Spain, Japan and Rep. of Korea. Therefore, majority of coastal states are unlikely to have yet undertaken proper utilization as well as rational management of marine living resources in their jurisdiction during the last two decades. The main target species groups which led the world fishery production to go up were Alaska pollock, cods, tunas, sardinellas, chub and jack mackerel and anchoveta. These stocks are largely expected to continue to contribute to the production. The fisheries resources which are unexploited, underexploited and/or lightly exploited at present and which will be contributed to the world production in future are identified with cephalopods, Pacific jack mackerel and Atlantic mackerel, silver hake including anchovies. These resources mainly distribute in the Pacific regions, especially FAO statistical fishing areas 67, 77 and 87. It was likely to premature to conclude that the new regime in the sea was only in favour of coastal states in fishey production.

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우리나라 서해남부해역의 새우류 어획물에 대한 자원생물학적 연구 -1. 어획물조성과 젓새우류의 산란시기- (fisheries Biology of Shrimps in the South Western Waters of Korea -1. Species Composition of Catches and Spawning Season of Acetes sp. for the Korean Shrimp Fishery-)

  • 오철웅;정인주
    • 한국수산과학회지
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    • 제35권3호
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    • pp.223-230
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    • 2002
  • 우리나라 새우류 생산의 $45\%$ 이상을 차지하는 서해남부해역의 새우어업에 대한 어획물 조성뿐만 아니라 주요 어획대상종인 젓새우류 (Acetes japonicus, A. chinensis)의 자원생물학적 특성치로서 성비, 체장과 체중 및 포란수와의 상관관계와 그들의 산란시기를 조사하였다. 어장에서 이용되는 주머니얽애그물의 어획물을 2000년 3월부터 2001년 2월까지 매월 채집하였다. 총 59종이 출현하였으며 새우류 14종, 어류 34종, 기타 갑각류 8종 및 두족류 3종으로 나타났다. 조사기간동안 새우류에 대한 부수어획물의 비는 2000년 4월에 2.42로 가장 높게 나타났으며, 2000년 8월과 2001년 2월을 제외하고 전 기간동안 1 미만으로 나타났다. 이러한 결과는 다른 지역이나 다른 국가에서 행해지는 새우어업과 비교해 볼 때 본 어법은 새우류에 대한 어구선택성이 탁월하고 다른 어종에 미치는 영향이 작다는 것을 지적해 주고 있다. 본 연구지역에서 출현량이 가장 많은 분류군은 젓새우류 (A.ja-ponicus, A. chinensis)로 나타났다. 이들의 평균 성비는 젓새우의 경우 1.44 $\pm$ 0.42, 중국젓새우의 경우 1.44 $\pm$ 0.43으로 나타나 두 종 모두 암컷이 더 많이 출현하는 경향을 보여주었으며, 특히 8월에 암컷의 비율이 가장 높게 나타났다. 젓새우의 평균 포란수는 4,812 $\pm$ 1,511개로 나타났으며, 중국젓새우의 평균 포란수는 5,561 $\pm$ 1,900개로 나타났다. 두 종에 있어서 성숙한 암컷개체는 5월에서 8월까지 나타났다. 또한 생식소 숙도지수 (GSI)는 7월과 8월에 높게 나타났으며, 7월에 가장 높은 것으로 나타났다. 이러한 결과는 그들의 산란시기가 여름이라는 것을 지적해 주고 있다.