• 수산해양기술연구
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• 제59권4호
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• pp.279-289
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• 2023

The United States enforces the seafood import regulations so-called the Marine Mammal Protection Act (MMPA), and by 2023, all exports of aquatic products and processed fish products by fisheries which have not obtained an "Comparability Finding" from the National Oceanic and Atmospheric Administration will be completely banned. Therefore, to respond to the US MMPA, it is critical to identify technologies and methods used in worldwide for reducing bycatch of marine mammals. In particular, marine mammals are frequently caught in five fisheries (trawl, gill net, trap, stow net and set net) in Korea, which is facing a great challenge. This study presented bycatch reduction methods by five fisheries, classified the methods by country, and suggested appropriate reduction methods which can be applied in Korea.

• 수산해양기술연구
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• 제48권1호
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• pp.20-28
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• 2012

The monofilament with 0.304mm of diameter was produced using a polybutylene succinate (PBS) resin, and a gill net was made by it. We investigated the impact of heat setting temperature on the mechanical properties, knot state and height of gill net. Heat treatment was carried out using the high pressure steam machine for 20 minutes at temperature of $55^{\circ}C$, $60^{\circ}C$, $70^{\circ}C$ and $75^{\circ}C$. Before heat treatment, the strength and elongation of PBS monofilament were estimated to be $48.1kg/mm^2$, 23.8% at unknot, $37.6kg/mm^2$, 18.8% at single knot, $26.6kg/mm^2$, 22.9% at double knot in dry condition, respectively. The strength and elongation of PBS monofilament with double knot were decreased as heat setting temperature increased, and the decreasing rate of strength was showed to be higher than that of elongation. It was not found any differences in strength and elongation of PBS monofilament yarn with double knot at the $65^{\circ}C$ and $70^{\circ}C$ of heat setting temperature by 5% significance of T-test, but there was a significant difference at the $70^{\circ}C$ and $75^{\circ}C$ of heat setting temperature. The net's height and length from leg to leg appeared no differences at the $70^{\circ}C$ and $75^{\circ}C$ of heat setting temperature. In results, it was investigated that the PBS monofilament gill net with the maximized physical properties could be manufactured at $70^{\circ}C$ of heat setting temperature using a high pressure steam machine for 20 minutes.

• 한국수산과학회지
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• 제42권1호
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• pp.78-82
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• 2009

We describe a catch experiment and the size selectivity of gill nets for male Japanese sandfish (Arctoscopus japonicus) caught near Gosung, Korea. The experiment, which was conducted between October and December 2007, examined six different mesh sizes: 36.4, 39.4, 45.5, 51.5, 53.0, and 57.6 mm. The catch was mostly Japanese sandfish (91.3%) and some others (8.7%). More male Japanese sandfish were caught with smaller mesh sizes and more females with larger mesh sizes. Relationships between the weight and fork length of the male and female Japanese sandfish were obtained. The relationship between the catch (Y) and mesh size of the gill net (X) was $Y=0.1773X^3-5.3753X^2+40.042X+26.846$ ($R^2=0.99$). The selection curve for male Japanese sandfish caught in the experiment was fit, via Kitahara's method, to a polynomial equation, which was $s(R={\exp}\{(-2.1391\;R^3+24.294\;R^2-88.289\;R+105.5)-5.180\}$, where R=l/m, and l and m are the fork length and mesh size, respectively.

• 수산해양기술연구
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• 제52권4호
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• pp.281-289
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• 2016

Spinyhead sculpin Dasycottus setiger, a species of cold water fish, is distributed along the eastern coastal waters of Korea. A series of fishing experiments was carried out in the waters near Uljin from June, 2002 to November, 2004, using the experimental monofilament gill nets of different mesh sizes (82.2, 89.4, 104.8, and 120.2 mm) to describe the selectivity of the gill net for the fish. The SELECT (Share Each Length's Catch Total) analysis with maximum likelihood method was applied to fit the different functional models (normal, lognormal, and bi-normal models) for selection curves to the catch data. The bi-normal model with the fixed relative fishing intensity was selected as the best-fit selection curve by AIC (Akaike's Information Criterion) comparison. For the best-fit selection curve, the optimum relative length (the ratio of fish total length to mesh size) with the maximum efficiency and the selection range ($R_{50%,large}-R_{50%,small}$) of 50% retention were obtained as 2.363 and 0.851, respectively. The ratios of body girth to mesh perimeter at 100% retention where the selection curve of each mesh size represented the optimum total length were calculated as the range of 0.86 ~ 0.87.

• 수산경영론집
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• 제7권2호
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• pp.23-61
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• 1976

• 생태와환경
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• 제55권4호
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• pp.285-293
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• 2022

어류 채집도구는 다양하며, 채집도구의 선택과 특성에 따라 채집되는 어류의 군집에 차이가 나타난다. 본 연구는 예당호에서 4개의 채집도구 (족대, 투망, 자망 및 삼각망)를 이용하여 어류 군집을 조사하고 비교하였다. 족대와 투망은 개체수를 채집하는 데 효율적이지 않았으나, 수변부에 서식하는 어류의 종 다양성이 높았다. 자망의 경우, 체장이 길거나 등지느러미 극조가 존재하는 어류가 주로 채집되었다. 삼각망에서는 가장 많은 개체수가 채집되었으며, 높은 종 선택성으로 인해 우점도가 높아지는 것으로 나타났다. NMDS 분석에서 족대, 투망 및 자망 간 채집되는 어류의 뚜렷한 차이가 나타났다. 비지도학습법인 Self-organizing map (SOM) 분석으로 자망에서는 체장이 큰 어류가 채집되는 반면 삼각망에서는 체장이 작은 어류가 채집되는 패턴 특성을 밝혀내었다. 채집도구에 따라 어류의 생태적인 특성과 종 다양성 효율이 다르게 나타났으며, 어류 군집조사 시 서식환경과 목적에 부합되는 채집도구를 선택할 필요성이 있다. 또한, 서식처 유형에 적합한 채집도구의 표준화로 연구자 간의 차이를 줄이는 방법의 제시가 요구된다.

• Ocean and Polar Research
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• 제37권2호
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• pp.161-177
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• 2015

This study analyzes the stock assessment of yellow croaker caught mainly by the Korean stow net and gill net fisheries focusing on single species and multiple fisheries. This study standardizes fishing efforts for the two fisheries using the general linear model and uses a surplus production model based on the exponential growth model. The Clarke Yoshimoto Pooley model estimates a maximum sustainable yield(MSY), an allowable biological catch(ABC), fishing efforts for MSY($E_{MSY}$) and for ABC($E_{ABC}$). The bio-economic model is used to estimate the maximum economic yield(MEY) and fishing efforts for MEY($E_{MSY}$). Also, the study employs an economic analysis to estimate the economic interaction between stow net and gill net fisheries. The economic analysis shows the profit accruing to the two fisheries from estimated ABC. Finally, the study compares TACs based on single species and single fishery to TAC based on single species and multiple fisheries. The study proposes that the TAC assessment is necessary for single species and multiple fisheries in order to preserve resources.

• 수산해양기술연구
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• 제39권2호
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• pp.143-151
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• 2003

본 연구에서는 자망에 대한 대게 수컷의 망목선택성을 구명하기 위하여 5종류의 망목 (m = 180, 210, 240, 270, 300㎜)으로 구성된 자망을 제작하고, 2002년 1월부터 2003년 3월까지 경북 죽변항 주변 수역에서 총 12회의 시험조업을 행하였다. 망목선택성 곡선의 계산에 사용될 데이터 확보를 위하여 어획된 대게 수컷의 전수에 대한 최대갑장 RL을 디지털 켈리퍼스를 사용하여 0.1㎜ 단위로 측정하였다. 망목선택성 곡선의 추정에는 Kitahara의 방법을 사용하였다. 대수 망목선택성 곡선의 함수로써 좌우대칭형인 2차식과 좌우비대칭형인 3 차식을 적용하였으며, 최소지승법을 사용하여 각 모델의 파라미터를 추정하였다. 본 연구에서 얻어진 결과를 요약하면 다음과 같다. 1. 자망에 대한 대게 수컷의 망목선택성 곡선은 Model 의 적합도 비교를 통하여 좌우비대칭형인 3 차식이 선택되었다. 2. 망목선택성의 결과는 망목이 커질수록 소형 수게의 혼획이 감소한다는 것을 나타낸다. 3. 망목선택성 곡선은 이하의 수식으로 표현된다. S(R) = S(RL/m) ＝ exp ((44.06 R³- 84.16 R²+ 52.30 R-5.46) - 5.17) 4. 선택률 1을 나타내는 최적 RL/m의 값은 0.549이며, 선택률 0.5, 0.25, 0.2를 나타내는 RL/m은 각각 0.356, 0.296, 0.281로 추정되었다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.193-194
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• 2006

This study describes the optimum size of a reef set in Korean coastal waters. Data were analyzed in relation to the weight and variety of fish species caught with a three-layer gill net. The results did not indicate a significant difference in the mean catch and mean number of fish species among the three different reef sets, 800, 1,600 and 2400 $m^3$.

• 수산해양기술연구
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• 제55권4호
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• pp.294-302
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• 2019

As a series of fundamental researches on the development of an automatic identification monitoring system for fishing gear. Firstly, the study on the installation method of automated identification buoy for the coastal improvement net fishing net with many loss problems on the west coast was carried out. Secondly, the study was conducted find out how to install an automatic identification buoy for coastal gill net which has the highest loss rate among the fisheries. GPS for fishing was used six times in the coastal waters around Seogwipo city in Jeju Island to determine the developmental status and underwater behavior to conduct a field survey. Next, a questionnaire was administered in parallel on the type of loss and the quantity and location of fishing gear to be developed and the water transmitter. In the field experiment, the data collection was possible from a minimum of 13 hours, ten minutes to a maximum of 20 hours and ten minutes using GPS, identifying the development status and underwater behavior of the coastal gillnet fishing gear. The result of the survey showed that the loss of coastal net fishing gear was in the following order: net (27.3%), full fishing gear (24.2%), buoys, and anchors (18.2%). The causes were active algae (50.0%), fish catches (33.3%) and natural disasters (12.5%). To solve this problem, the installation method is to attach one and two electronic buoys to top of each end of the fishing gear, and one underwater transmitter at both ends of the float line connected to the anchor. By identifying and managing abnormal conditions such as damage or loss of fishing gear due to external factors such as potent algae and cutting of fishing gear, loss of fishing gear can be reduced. If the lost fishing gear is found, it will be efficiently collected.