• 수산해양기술연구
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• 제37권3호
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• pp.159-162
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• 2001

낙지 주낙 어장의 환경요인이 어획량에 미치는 영향을 조사하기 위하여 1997년 1월부터 7월까지 여수연안에서 수온, 염분, 밀도, 풍향, 풍속등과 어획량을 각각 조사하고 이들을 서로 비교 분석한 결과를 요약하면 다음과 같다. 1) 풍향별 어획량은 남동풍일 때 가장 많았고 북서풍일 때 가장 적었으며, 풍속별 어획량은 2일 때 가장 많았고 그보다 커질 경우는 감소하였다. 2) 물때별 단위 노력당 어획량은 15물에서 가장 많고 4물에서 가장 적으며. 조류가 차차 약해지는 11∼14물 사이의 어획량이 조류가 차차 강해지는 1∼4물 사이의 어획량보다 많았다. 3) 썰물과 밀물 때의 어획량은 간조에서 만조로 바뀐 후 1시간 동안의 구간, 즉 간조에서 물이 들기 시작한지 1시간 동안에 어획량이 가장 많았고. 썰물 시각대 보다는 밀물 시각대에 어획량이 비교적 많은 경향이었다

• 수산해양기술연구
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• 제37권4호
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• pp.326-330
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• 2001

낙지주낙 어장의 환경요인이 어획량에 미치는 영향을 조사하기 위하여 1997년 1월부터 7월까지 여수연안에서 풍향, 풍속, 물때별 및 조업 시각대별로 어획량을 각각 사하고 이들을 서로 비교 분석한 결과를 요약하면 다음과 같다. 1) 풍향별 어획량은 남동풍일 때 가장 많았고 북서풍일 때 가장 적었으며, 풍속별 어획량은 2일 때 가장 많았고 그보다 커질 경우는 감소하였다. 2) 물때별 단위 노력당 어획량은 15물에서 가장 많고 4물에서 가장 적으며, 조류가 차차 약해지는 11∼14물 사이의 어획량이 조류가 차차 강해지는 1∼4물 사이의 어획량보다 많았다. 3) 썰물과 밀물 때의 어획량은 간조에서 만조로 바뀐 후 1시간 동안의 구간, 즉 간조에서 물이 들기 시작한지 1시간 동안에 어획량이 가장 많았고, 썰물 시각대 보다는 밀물 시각대에 어획량이 비교적 많은 경향이었다.

• 수산해양기술연구
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• 제58권4호
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• pp.310-316
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• 2022

Giant pacific octopus, Enteroctopus dofleini, is a large mollusk distributed in the East Sea of Korea. In this study, the catch status of giant pacific octopus by drift line fishery and the effect of sea temperature on fishing ground were investigated in Goseong-gun, Gangwon-do, which is the central coast of the East Sea. The average catch of giant pacific octopus in Gangwon-do was 1,570 tons over the past ten years, and it accounted for 21% in 2008 and 44% in 2021 compared to the total catch in the East Sea during the same period. Such data indicates that the catch in Gangwon-do has recently increased. In this study area, giant pacific octopus weighing 1.1-5.0 kg dominated accounting for 56% of the total individuals, and followed by those weighing 1 kg or less. However, the ratio of catch of giant pacific octopus over 5.1 kg tended to increase in 2021, which is thought to be related to the sea temperature that affected the fishing ground. The main depth of fishing ground was from 21 m to 50 m in this area and fishing grounds were widely distributed throughout the season except summer. Fishing ground was formed with the conditions of bottom sea temperature under 10℃ and was diminished by moving of giant pacific octopus to deeper depth with conditions of bottom sea temperature over 18℃.

• 수산해양기술연구
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• 제44권1호
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• pp.1-9
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• 2008

This study aims to reduce the bycatch of young fishes and other species in the octopus(Octopus vulagris, Octopus dolfleini) trap fishery on the East Sea, Korea. We carried out field experiments and tank experiments to verify the fishing efficiency and bycatch with the different 8 types of trap. 4 of them had mesh size 20, 35, 55 respectively and 75mm, 2 of them with escape ring of diameter 30mm and 50mm and 2 of them with escape device. The gap was 20 and 40mm respectively. The mesh sizes of the traps with ring and frame were 20mm. The traps with mesh size 20 and 35mm were not reasonable because it could fish under 300g octopus as bycatch which is not permitted by the Korean fisheries regulations. The catch number of octopus over 300g by traps with escape ring of diameter 30mm was 53. The catch of trap with mesh size 20mm was 54. The catch of trap with mesh size 35mm was 53. There is no significant difference among them. The catch number of octopus over 500g that is fishermen's favorite one was 46 in the trap with escap ring. The diameter of was 30 mm and the catch of trap with mesh size 20mm was more 3 catch and the catch of trap with mesh size 35mm had 6 more catch. Fishermen wanted to catch over 500g octopus because the octopuses had commercial value. The traps with escape ring can be replaceable with he traps with mesh size 20 or 35mm because the trap is suitable to conserve the octopus resources and keep the fishermen's fishing substantiality.

• 수산해양기술연구
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• 제37권3호
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• pp.155-158
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• 2001

낙지 주낙 어장의 환경요인이 어획량에 미치는 영향을 조사하기 위하여 1997년 1월부터 7월까지 여수연안의 가막만 어장에서 수온, 염분 및 밀도 등과 어획량을 각각 조사하고 이들을 서로 비교 분석한 결과를 요약하면 다음과 같다. 1) 낙지 주낙 어장에서 I~7월에 걸친 수온과 염분 및 현장밀도의 분포범위는 각각 401~23. $6^{\circ}C$, 31.7~34.5$\textperthousand$ 및 $\sigma$$_{t}$ 21.30~27.81였고, 어획량은 이들 세 요인의 값이 각각 17~$20^{\circ}C$, 33.0~33.5$\textperthousand$ 및 $\sigma$$_{t}$ 22.5~24.0 범위일 때 높아지는 경향이었다. 2) 낙지의 조업당 어획량은 10~16마리로서 비교적 낮은 편이며, 월별로는 1~2월에 적고, 3월부터 상승하기 시작하여 5~6월에 가장 높았다.

• 수산해양기술연구
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• 제37권4호
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• pp.321-325
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• 2001

낙지주낙 어장의 환경요인이 어획량에 미치는 영향을 조사하기 위하여 1997년 1월부터 7월까지 여수연안의 가막만 어장에서 수온, 염분 및 밀도등과 어획량을 각각 조사하고 이들을 서로 비교 분석한 결과를 요약하면 다음과 같다. 1) 낙지 주낙 어장에서 1~7월에 걸친 수온과 염분 및 현장밀도의 분포범위는 각각 4.1~$23.6^{\circ}C$23.6, 31.7~34.5$\textperthousand$및 $\sigma$$_{t}$, 21.30~27.81였고, 어획량은 이들 세 요인의 값이 각각 17~$20^{\circ}C$, 33.0~33.5$\textperthousand$및 $\sigma$$_{t}$ 22.5~24.0 범위일 때 높아지는 경향을 보였다. 2) 낙지의 조업당 어척량은 10~16마리로서 비교적 낮은 편이며, 월별로는 1~2월에 적고, 3월부터 상승하기 시작하여 5~6월에 가장 높았다.

• 수산해양기술연구
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• 제58권2호
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• pp.95-105
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• 2022

In this study, the fishery status of the octopus pot fishery in the east coastal sea were investigated, and the fishing performance of each pot shape was compared and analyzed. The fishery status survey was conducted through listening surveys at Jukbyeon Port, Uljin Port and Pohang Daebo Port in Gyeongbuk Province, and the amount of fishing gear used, fishing method, size and loss of octopus pot fishery was investigated. On the east coastal sea, octopus is one of the commercially important fish stocks and is caught in inshore pots, inshore combos, inshore gillnets and offshore pots. Among these fishing methods, pot fishing yields the highest catch. The shape of the pot differs depending on the region. In Uljin (Jukbyeon Port and Hupo Port), Gyeongbuk, rectangular type net pots are mainly used, and in Pohang (Daebo Port) in Gyeongbuk, drum-type pots are mostly used. Enteroctopus dofleini accounts for more than 90% of the catch of octopus. For the octopus fishing performance test by trap type, three types of traps (rectangular pot, drum pot and cylinder pot) were used on the coastal sea of Pohang Daebo. As a result, the total catch by pot shape was shown in the order of rectangular-type pot > drum-type pot > cylinder-type pot. The catch of octopus, the target species, was in the following order: rectangular-type pot > drum-type pot > cylinder-type pot. Such result shows a significant difference (Mann-Whitney test, p<0.05).

• 수산해양기술연구
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• 제41권4호
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• pp.271-278
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• 2005

In order to study the catch situation of the octopus pot fishery in the coastal waters of Gangneung, catch quantities and weight per month and depth, the soaking time & loss of fishing gear were studied based on 62 fishing times (1 set consisted of 150 pots which is equivalent to 1 fishing time) over a period of 10 months from February to December 2003 using commercial fishing vessels and training ships. The monthly CPUE was generally high in the months of june - September, and during this period July showed the highest quantity (134g/pot, 19.21kg/haul). In consideration of the fact that octopus below the weight of 2kg is protected in foreign countries, the majority of the catch was small with 76% (486 octopuses) below 1kg. The octopus catch quantity was high in depth of more than 40m, and the average catch number per set of pots in depths of over 50m was the highest with 13 octopuses. CPUE(g/pot) was the highest at a depth of over 60m recording 101. In terms of catch quantity per soaking time (4-18 days) the highest was on the 7th day, and 13-18 days also recorded high catches, and this suggests the possibility of ghost - fishing with the loss of fishing gear. Loss of fishing gear was the highest in terms of loss frequency and amount at depths of 20-30m. Consequently, it seems that octopus pot fishing at depths of more than 30m would relieve friction with other types of fishing and increase fishing efficiency.

• 수산해양기술연구
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• 제45권3호
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• pp.144-150
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• 2009

The choice behavior of the octopus in response to the environment-friendly colored sinker for octopus driftline and the sinker's fishing effect were studied under experimental conditions in the water tank and the field. The colors of the sinkers used for the experiment are white, black, yellow and green. Artificial baits are attached to the sinkers in order to attract the octopuses in the experiment. In the water tank experiment, two sinkers of two different colors are placed in a compartmentalized corner of the rectangular tank, and a CCD camera records the choice behaviors of the octopuses to the colored sinkers. In the field experiment, the catch investigation of octopus for each colored sinker was conducted 14 times in total by using 2(A, B) commercial fishing boats at the coast of Gangneung within 30m of depth in 2006. The number of colored sinkers per operation was a total of 24-40 pieces with the same number of sinkers individually for four colors. As a result, it was found that the octopus selected white the most followed by black and yellow in their choice of colored sinkers in the water tank experiment, and green was the lowest in their choice. Even in the field experiment, the sinkers of white and black showed a higher catch of octopus than the sinkers of yellow and green.

• 한국수산과학회지
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• 제53권1호
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• pp.57-66
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• 2020

The purpose of this study was to provide information about annual variations in catch size and changes in reproductive biology in the common octopus Octopus vulgaris, a commercially important species. Samples were collected from coastal waters off Gyeongnam, Korea, by coastal trap and coastal complex fishery from February to December 2018. Octopus vulgaris have been decreasing in this region since 2007 and catch prices have been increasing. The mantle length (ML) of O. vulgaris ranged from 1.2 to 21.2 cm and body weight ranged from 42.6 to 5,537 g. The sex ratio differed significantly from what was expected, at 0.45:0.55 (P<0.05). Mature females were found from February to December, except in October and November, and males occurred from February to December, except in October. The gonadosomatic index value was higher from May to September than in other months. The total number of eggs in fecund individuals ranged from 40,280 in 578.1 g of body weight to 138,994 in 1,666.5 g of body weight. The relationship between body weight and fecundity was F=76.486BW^1.0087 (r²=0.7897). At 50% group maturity, average weight was estimated to be 636.35 g, while it was 969.30 g at 75% maturity and 1736.55 g at 97.5% maturity. This study highlights changes in catch size and reproductive biology between 2007 and 2018. These results provide basic evidence that may be used to establish regulatory policy for O. vulgaris fisheries.