• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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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℃.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.199-204
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• 2022

The Pacific giant octopus (Enteroctopus dofleini) is one of the most important species in the East Sea fishery of Korea. The annual production of Pacific giant octopus in 2021 was 3,880 metric ton between Gangwon province and Gyeongsangbuk province. Most of the fishing gears for the octopus fishery were based on behavioral properties such as thigmotaxis and chemotaxis. Wooden octopus box is also one of the fishing gears, which is application of thigmotaxis for the octopus capture in fishing industry. In this study, the tank experiments were designed to examine the behaviour and the effect of surface roughness to the infiltration of the octopus quantitatively. Three different types of octopus boxes were used for the experiments with different surface roughness on the average of 701.6 ㎛, 141.7 ㎛ and 2.09 ㎛ for each gear. 22 trials were conducted from June to September 2021. The normality of the experiments was tested using Shapiro-Wilk normality test (p-value < 0.05). The significance of results was conducted by Kruskal-Wallis rank sum test (Chi-squarded = 21, Degree of freedom = 3, p-value < 0.05). The use of wooden octopus box with rough surface was found to enhance the catch efficiency and observe infiltration behaviour of the octopus frequently.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.2
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• pp.154-161
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• 2014

Maturity and spawning of the giant Pacific octopus, Octopus dofleini was investigated based on the samples collected in the coast of Gangwondo, East Sea, from January to December in 2009. Individuals of mature stage had a higher occurrence rate from February to May, and gonadosomatic index (GSI) also showed a higher value from February to May than the other months. For that reason, the spawning period was estimated from February to May with the main spawning period from March to May. The total number of eggs in the fecundity (F) ranged from 9,045 in 11.0 kg (TW) to 148,682 in 16.5 kg (TW), which was proportional to total weight (TW), and the relationship between total weight and fecundity was $F=0.185{\times}TW^{2.238}$ ($R^2=0.389$). The total weight at 50% group maturity (TW0.5) of female was estimated to be 12.2 kg.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.1-8
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• 2004

The single line hook fishery for giant pacific octopus, Parotopus dofleini is one of the important in coastal Kangwon-do of Korea, where was caught an average of 4,000 ton during the period of 1996~2000. The fishing gear is consisted of a single buoy line, a buoy and a hook. In this study, the responses of giant pacific octopus to single line hook gear were examined in an experimental tank using a video camera in order to know hooking mechanism and improve hook. Giant pacific octopus tend to envelop the bait with their arms by rush or slowly swimming towards it. When they rush to the bait, they show much feeding behaviour as withdrawing after enveloping the bait using two arms. But when they approach with slowly swimming to bait, they show feeding behaviour as stopping after enveloping the bait using one arm. and then, the highly hooking rate appeared more often in the case of latter then former. The average feeding time on a sardine, giant pacific octopus and pork fat showed the range of 1 to 30 min, 10 to 50 min, and 50 min to over 1 hour, respectively. This indicates that it takes longer time for giant pacific octopus to eat the tough meat than the soft meat. The performance concerned with hooking showed that the 'B' type hook with a short shank was more favorable than the 'A' type hook with a long shank. However, the 'A' type hook has the advantage of easy dropping out caught octopus, compared to the 'B' type.