Interviews and boarding surveys were conducted in order to understand the actual usage of octopus pot in the coastal composite fishery in Jeollanam-do. According to the results of the interviews conduced by visiting the areas (Goheung, Yeosu and Wando), the number of octopus pots per nine-ton vessel were 30,000-80,000, and the number of daily usage pots were 7,000-10,000. The number of octopus pots per four-ton vessel was 40,000, and the number of daily usage pots were 4,000. As a result of the survey on two octopus pot fishing boats (9.77-ton and 4.99-ton) in Yeosu area, the daily catch weight of 9-ton class vessel was the minimum of 66.9 kg and the maximum of 159.6 kg. The daily catch weight of the four-ton class fishing vessel was from 31.3 kg to maximum 85.6 kg. The average number of octopus pot used per day in the nine-ton class vessel was 6,821 (the minimum of 6,031 and the maximum of 7,697) and 3,181 (the minimum of 2,282 and the maximum of 3,878) in the four-ton class vessel.

To compare the catches made using gillnets, trammel nets, and gillnets with supporting lines, several experiments were conducted with commercial vessels near Uljin and Pohang in Eastern Korea between July 2010 and May 2011. Two sets of 13 different nets were used, including 5 panels of gillnets and trammel nets each with stretched mesh sizes of 7.6, 9.1, 10.6, 12.1, and 13.6 cm and 3 panels of gillnets with a mesh size of 9.1 cm with supporting lines with different line spacing. The outer (stretched) mesh size of the trammel nets measured 51.5 cm. The target fishes of the fishing nets were various types of flounders. The catch rate of flounders was 50.7% of the total catch in weight. The total catch for all nets was 443.8 kg. The predominant species was pointhead flounder (Cleisthenes pinetorum). The total catch by trammel nets was 1.4 times that of the comparable gillnets. But more pointhead flounder were caught by gillnets than by trammel nets, though there was no significant difference. Fishermen catching the pointhead flounder in Korea said that there was no need to use trammel net to catch it; this was an unexpected finding compared to the findings of other flounder fisheries. The amounts of roughscale sole, brown sole, and blackfin flounder caught by trammel nets were greater than those caught by gillnets. The mean lengths (standard deviation) of blackfin flounder, pointhead flounder, brown sole, and roughscale sole were 21.0 (4.57), 22.9 (3.40), 24.7 (4.90), and 28.3 (5.43) cm, respectively; there were significant differences in mean length (p < 0.00001). Therefore, in order to catch flounder efficiently, the fishing nets and mesh size should be chosen according to the target species. One advantage of using supporting lines is that it prevents breakage by strengthening the material especially when utilized on a rough bottom. Catch by using gillnet with supporting lines was not greater than that by using trammel net for the conservation of fisheries resources.