• 제목/요약/키워드: Gill-net

검색결과 178건 처리시간 0.021초

Investigation on bycatch reduction methods of marine mammals for fishing with gill net, trap, trawl, stow net and set net (자망, 통발, 트롤, 안강망, 정치망 어업에 대한 해양포유류 혼획 저감 연구 조사)

  • Kyu-Suk CHOI;Hyun-Su JO;Myounghee KANG
    • Journal of the Korean Society of Fisheries and Ocean Technology
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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.

Effects of heat setting temperature conditions on the mechanical properties of Polybutylene succinate (PBS) monofilament yarn after net-making (편망 후 열처리 온도가 PBS 모노필라멘트사의 물리적 특성에 미치는 영향)

  • Park, Seong-Wook;Kim, Seong-Hun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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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.

Size Selectivity of Gill Net for Male Japanese Sandfish (Arctoscopus japonicus) off Gangwon in winter (강원 영안 겨울 도루묵(Arctoscopus japonicus) 수컷의 자망에 대한 어획선택성)

  • Jeong, Eui-Cheol;Park, Hae-Hoon;Bae, Bong-Seong;Chang, Dae-Soo;Kim, Chan-Seob;Choi, Soo-Ha;Cha, Hyung-Kee
    • Korean Journal of Fisheries and Aquatic Sciences
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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.

Size selectivity of the gill net for spinyhead sculpin, Dasycottus setiger in the eastern coastal waters of Korea (동해안 자망에 대한 고무꺽정이 (Dasycottus setiger )의 망목 선택성)

  • PARK, Chang-Doo;BAE, Jae-Hyun;CHO, Sam-Kwang;AN, Heui-Chun;KIM, In-Ok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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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.

Species Composition of Fish in Yedang Reservoir and Characteristics by Sampling Gears (예당호 어류 종조성과 채집도구에 따른 어류 특성)

  • Tae-Sik Yu;Chang Woo Ji;Yong Jun Kim;Gun Hee Oh;Young-Seuk Park;Ihn-Sil Kwak
    • Korean Journal of Ecology and Environment
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    • 제55권4호
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    • pp.285-293
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    • 2022
  • Sampling gears for collecting fish are diverse, and the community of fish varies according to the selection and characteristics of the sampling gears. The present study compared the characteristics of fish communities in Yedang reservoir using four sampling gears (kick net, cast net, gill net, and fyke net). The kick net and cast net were inefficient in collecting the number of individuals. However, they increased the species diversity of fish inhabiting the waterfront. Although not many individuals were collected, the gill net mainly collected large fish. The largest number of individuals was collected in the fyke net, and the dominance was high due to the high species selectivity. Through Self-Organizing Map (SOM) analysis, large fish were collected in the gill net, whereas small fish were collected in the fyke net. The characteristics and efficiency of the fish differed depending on the sampling gears. It is expected that researchers will need to use it appropriately according to the characteristics of the sampling gears when investigating the fish community.

A Stock Assessment of Yellow Croaker using Bioeconomic Model: a Case of Single Species and Multiple Fisheries (생물경제모형을 이용한 참조기의 자원평가에 관한 연구 - 단일어종·다수어업 사례를 중심으로)

  • Sim, Seonghyun;Nam, Jongoh
    • 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.

Size selectivity of gill net for male snow crab, Chionoecetes opilio (자망에 대한 대게 수컷의 망목 선택성)

  • 박창두;안희춘;조삼광;백철인
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • 제39권2호
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    • pp.143-151
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    • 2003
  • A series of fishing experiments was carried out in the waters off the east coast of Korea from January, 2002 to March, 2003, using gill nets of different mesh sizes (m = 180, 210, 240, 270, and 300 ㎜) to determine the size selectivity of gill net for male snow crab Chionoecetes opilio. The maximum carapace length (RL) of each male snow crab caught in the fishing experiment was measured. The master curve of mesh selectivity was estimated by applying the extended Kitahara's method. Two kinds of functional models, quadratic function and cubic function were used to express logarithmic selectivity curve and were fitted to the data using the method of least squares. The obtained results were summarized as follows; 1. The cubic function of asymmetry was chosen to determine the selectivity curve of gill net for male snow crab from the model deviance comparison. 2. The result of size selectivity showed that the catch number of small male crab was getting decreased according to the increase of mesh size. 3. The optimum value (RL/m) was 0.549 and the RL/m was estimated to be 0.281, 0.296, and 0.356 when the retention probability were 0.2, 0.25 and 0.5, respectively.

Optimum Size of a Reef Set in the Southern Water of Korea (한국 남해안의 1개 단위인공어초의 적정 규모)

  • Kim, Chang-Gil;Kim, Ho-Sang;Seo, Jang-Woo;Jung, Geum-Chul
    • Proceedings of the Korean Society of Marine Engineers Conference
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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 $m^3$.

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A fundamental study on the installation methods of automatic identification buoy on coastal gill net (연안자망 부이에 어구자동식별 장치 설치방안에 관한 기초적 연구)

  • HEO, Nam-Hee;KANG, Kyoung-Bum;KOO, Myeong-Seong;KIM, Keun-Hyong;KIM, Jong-Bum;JWA, Min-Seok;KIM, Jun-Teck;JOUNG, Joo-Myeong;KIM, Byung-Yeob;KIM, Suk-Jong
    • Journal of the Korean Society of Fisheries and Ocean Technology
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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.