• 수산해양기술연구
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• 제42권1호
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• pp.44-53
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• 2006

The expansion of near shore aquaculture is feasibility of moving aquaculture facilities into the open ocean. Numerical modeling technique using finite element method was used to enable the optimum design and evaluation of submersible aquaculture cage system. The characteristics of mooring loads response in mooring lines under waves and current and their response amplitude operators were calculated for single and three point mooring configuration at the surface condition and submerged one. The static mooring loads without wave and current loading were similar for both the surface and submerged configuration. It was calculated that three point mooring was more adequate than single point mooring for the mooring configuration of submersible aquaculture cage system. The wave induced response amplitude operators for the single point mooring configuration with the influence of currents were identical to those without the influence of currents.

• 수산해양기술연구
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• 제48권1호
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• pp.40-50
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• 2012

This study aims to analyze the performance of a submersible fish cage which was designed for developing an economical cage system can be applied in korean aquaculture environment easily. To analyze the performance of the designed cage a model test was carried out. In the test, inclination changes of the upper frame and mooring tensions of model cage were measured during the submerging and surfacing motion in still water and wave condition (period: 2s, wave height: 0.1, 0.2, 0.3m). As a result, in the still water condition the model cage kept horizontal balance and inclination degree of the upper frame was about $1^{\circ}$. In the wave condition, the model cage showed bilateral symmetric up-and-down motion but the average inclination degree of the upper frame was about $0^{\circ}$. When the model cage reached at a depth of 1m, the up-and-down motion of the cage was decreased by 12% compared with that of at the surface (period 2s, height 0.3m). In the same wave condition, the maximum and average line tension under the bottom position were about 8% and 11% respectively compared with that of at surface.

• 수산경영론집
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• 제52권3호
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• pp.27-38
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• 2021

This study is aimed to figure out the productivity and variability of cage-aquaculture changes. According to the analysis, the productivity of major fish species has been increasing, except mullet. Although the regional productivity has decreased in the last two years, it has been on the rise considering as a whole. Gyeongsangnam-do showed the highest level of productivity by region. Productivity by species was also higher than other regions in the cases of rock fish, mullet and sea bream followed by productivity of Chungcheongnam-do. The production of marine cage-culture in Jeollanam-do is the second largest in Korea in value/weight while its productivity is lower than that of Chungcheongnam-do. When it comes to comparison by region, Gyeongsangnam-do shows the lowest productivity variation. And Jeollanam-do shows the second-lowest variation in productivity that is only about half of that of Chungcheongnam-do province. Thus, it is found that Jeollanam-do region has an advantage in management stability while its productivity is low. On the other hand, productivity by species was also analyzed. Gyeongsangnam-do has the highest productivity by species for rock fish, mullet and sea bream whereas rock bream productivity is the highest in Jeollanam-do. Therefore, it probably needs to reflect these results when choosing regional-focused incubation fish species.

• 수산경영론집
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• 제46권2호
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• pp.13-29
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• 2015

The abalone aquaculture has been very rapidly developed in Korea. Annual production quantity was less 200 tons before 2000th, it have been increased to over 9,000 tons in 2014. Also Abalone export amounts have been over 20 million dollars. The reason of rapid growth of Abalone aquaculture in Korea is due to high level profit ratio. Then now many fishing officers and other aquaculture fishers want to participate with abalone aquaculture newly. However Recent Abalone aquaculture in Korea is faced some problems. Aspects of production environmental status of fishing grounds are more aggravate, and then abalone aquaculture is exposed to various disease, and death rate of young abalone is higher. And aspect of management, the aquaculture cost is more increase. The demand of abalone also is depressing recently, this cause to come down the production price. In this viewpoint, Management analysis of abalone aquaculture in Korea is helpful for decision making of general aquaculture fisher want to participate newly. The analysis is practiced two aspects. One is index analysis, and the other is Break-even-point(BEP) analysis. The result of index analysis, average net profit rate has shown 28.0%, however the Regional difference has excessive. That is, Wando(major) has shown 39.4%, and Haenam province has shown 14.2%. On the other hand, the more scale has shown higher profit rate by aquaculture scale. And the result of BEP analysis, average has shown 93 cage number per abalone aquaculture household, and Wando(major) has shown 56 cage number, Haenam province has shown 131 cage number. The lower production abalone price of recent means higher BEP level.

• 한국해안·해양공학회논문집
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• 제23권1호
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• pp.63-69
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• 2011

본 연구에서는 일정한 공극율을 갖는 투과성 그물망으로 이루어진 원통형 양식시설물에 작용하는 파랑하중을 고유함수전개법을 사용하여 해석하였다. 그물망에서의 경계조건식으로 그물망을 통과하는 속도값은 그물망 전후의 압력차에 선형적으로 비례한다는 Darcy의 법칙을 적용하였다. 그물망의 공극율 계수와 양식시설물의 잠긴 위치(부상식, 착저식)를 변화시키면서 양식시설물에 작용하는 파랑하중과 파도응답을 살펴보았다. 착저식 양식시설물에 작용하는 파랑하중이 부상식과 비교하여 크게 감소하며, 그물망의 공극율이 양식시설물의 파랑하중과 양식시설물 주변의 파형을 줄이는데 중요한 역할을 함을 밝혔다.

• 수산해양기술연구
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• 제60권2호
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• pp.186-193
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• 2024

Most fishing nets used in fish cage aquaculture are made of synthetic fibers such as polyamide (PA) and polyethylene (PE). Therefore, it is challenging to maintain the internal volume of the fish cage due to biofouling, which can increase the load on the cage or reduce dissolved oxygen levels by impeding smooth current flow. To address this issue, research has been conducted to replace conventional synthetic fiber cage nets with brass nets, demonstrating certain benefits such as improved productivity and ease of fish cage management. However, given the need for a more thorough examination of brass fishing net weaving technology and performance, this study assessed the optimal weaving method for brass fishing nets to be used in fish cages. Additionally, it provided essential data for the practical application of brass fishing nets by evaluating their weight, tensile strength, elongation, fatigue resistance, and wear resistance. The study concluded that weaving brass fishing nets using the chain link method ensures durability, ease of installation, and compact storage in a scroll-like form. Moreover, due to their superior fatigue and wear resistance properties, brass nets can offer increased utility if appropriate net diameter and length are selected to compensate for their higher weight per unit area and relatively higher cost compared to existing fiber fishing nets.

• 한국수산과학회지
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• 제55권5호
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• pp.598-611
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• 2022

The aim of this study was to investigate the range of influence of aquaculture activities in fish cage farms located on the southern coast of Korea (Farm A and B in Hadong, Farm C in Tongyoung, and Farm D in Geoje) by analyzing the distribution and characteristics of polychaete communities. Farm A and B showed remarkably high aquaculture intensity, and as a result, the polychaete communities near the farms were heavily polluted. However, there was a difference in the polychaete communities at a distance greater than 30 m from farm A and B, which may be due to topographical differences. The effect of the aquaculture activity of Farm C was only observed below the farm, however, the influence of aquaculture activities Farm D was maintained over a relatively long distance. According to the results of this study, the effect of the fish cage culture was mainly influenced by factors related to the production of fish, such as the stocking amount and the amount of food supply. Moreover, the distance at which the influence of aquaculture activity was observed was found to be closely related to the topographical characteristics and flow velocity around the farms.

• 한국어류학회지
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• 제29권1호
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• pp.41-51
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• 2017

어류양식용 가두리로서 동합금가두리망의 현장활용 가능성을 파악하기 위해 양식어류인 2년산 참돔을 동합금망과 합성섬유망에서 9개월 동안 각각 사육관리하면서 참돔에 미치는 양식생물학적 및 병리학적 영향을 조사하여 생물학적 안전성을 평가하였다. 동합금가두리망은 지름 25 m, 깊이 10 m의 규모로 제작하여 경남 통영시 욕지면 주변해역 연구교습어장에 설치하였다. 동합금가두리망과 합성섬유망에서 사육한 참돔의 생존율은 각각 99.75%와 99.70%로 유의한 차이는 나타나지 않았다. 일일체중성장률은 동합금가두리망과 합성섬유망에서 각각 2.13 g/day와 1.65 g/day로 동합금가두리망에서 사육한 참돔의 성장률이 빠른 것으로 나타났다. 혈액성분 분석에 따른 건강도 평가는 합성섬유망에 비해 동합금가두리망에서 양호한 것으로 나타났다. 가두리망 종류별 사육중인 참돔의 구리와 아연의 축적은 다른 기관에 비해 생식소에서 축적이 높게 나타났으며, 가용부분인 근육내 중금속 축적은 허용기준치에 비해 매우 낮았다. 또한 병원체 감염조사결과 동합금가두리망과 합성섬유망에서 기생충은 Microcotyle tai, 세균은 Vibrio alginolyticus 외 5종 등이 공통적으로 관찰되었으나, 동합금가두리망에서 Vibrio속의 세균 감염률에는 다소 차이를 보여 항균작용이 있을 것으로 예상된다. 따라서 동합금가두리망의 시스템안정성, 재활용가능성, 항균성 및 식품안전성 등을 고려할 때 어류양식용 가두리로 현장에서 활용이 가능할 것으로 여겨진다.

• 한국패류학회지
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• 제30권1호
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• pp.9-15
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• 2014

완도에서 주로 사용되는 4열 10행의 가두리 1조를 조합한 형태로 구성된 PE프레임의 내파성 전복가두리를 1/20로 축소하여 모형을 만들고 유체흐름 가시화 실험을 통해 전복가두리 주위의 해수의 흐름을 파악했다. 실험의 결과를 검증하기 위해 노화도 현장의 전복양식 가두리의 내부와 외부의 유속을 측정하였다. 연구의 결과는 아래와 같다. 1. 모형실험에서 전복가두리에 입사하는 해수는 대부분 첫 번째 단위 가두리 (칸) 를 통과하지 못하였다. 2. 모형 전복가두리 중앙 부위에서는 가두리에서 수조바닥으로 향하는 흐름을 관측하였다. 3. 모형 전복가두리의 외측 열을 빠져나가는 유체의 유속이 내측 열을 빠져나가는 유체의 유속보다 빨랐다. 4. 노화도의 현장 양식가두리의 2 m앞의 조류의 유속은 0.11 m/sec였지만 가두리 칸 내부의 유속은 0.0009 m/sec로 거의 움직임이 없었다. 5. 현재의 전복가두리 형태는 해수의 유통이 원활하지 않아 가두리 내부로 새로운 해수를 공급하기 어려울 것으로 판단된다.

• 수산해양기술연구
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• 제56권2호
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• pp.83-93
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• 2020

In fisheries, the importance of designing efficient fish cages is being emphasized as aquaculture has become more production than capture fishing. Particularly, the gravity cage system is one of the popular fish cage system in Korea. Currently, gravity cages of various shapes and sizes are being widely designed and installed in offshore and inland seas. The cage is subject to external forces, such as currents and waves, and the shape of the structure and tension on the ropes changes according to these external forces. Thus, it is important to accurately calculate these dynamic behavior, including the external forces and tension on the structure during the design stage. In this study, three types of cage systems with an equal internal volume of 8000 ㎥ were analyzed using mass-spring models and their behavior was interpreted through simulations. These simulations were used to analyze the behavior and tension of the ropes in response to currents and waves to aid in the selection of individual cage sizes for a given total volume. The numerical calculation results indicate that depending on the flow rate, the most resistant system is System 1, which has eight strays, and System 2 and System 3 have 69.4% and 54.8% of the resistance of System 1. Further, total resistance increased as the number of cages increased for all flow rates.