• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.9-16
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• 2016

This study was conducted to analyze fishing capacity and bycatch by mesh size and entrance size of spring net pot conducted by water tank and field experiment. The water tank experiments were conducted by using traps with mesh size of 22 mm and entrance size of 120 mm and 140 mm, respectively in the water tank of NIFS. The field experiment was conducted using 5 kinds of spring net pot with mesh sizes of 20 mm, 22 mm, 35 mm and entrance size of 120 mm, 130 mm, 140 mm, 360 mm by coastal trap fishery vessel operating around the area of Geoje island. In the result of water tank experiments, the catch of conger eel was 1.5 times higher when using trap with entrance size of 140 mm than that of 120 mm. In the field experiment, when using same mesh size, the larger the entrance size, the higher amount of conger eel catch, bycatch and number of bycatch species. When using the same entrance size, the larger the mesh size, the lower amount of conger eel catch and number of bycatch species, whereas the amount of bycatch showed increasing trend.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2265-2270
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• 2008

It was studied to the displacement and the amount of catch for migratory fishes with NOAA/AVHRR SST(Sea Surface Temperature) from 1988 to 2000 in the Korean Seas. The analyzed results from SST data showed generally the oceanic warming trend in the Korean Seas. On the increasement of SST, the distributed areas of migratory fishes which living in the warm waters were displaced gradually to the northward directions(high latitude) and then the amount of catch was increased during this studied periods against to migratory fishes which living in the cold waters.

• The Korean Journal of Ecology
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• v.18 no.4
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• pp.483-491
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• 1995

This study examined the relationship among catch-fire, burning, maximum temperature (MT), amount of combustion-heat (ACH), and combustive time (CT) in heating temperature treated with the same amount of each organ of Miscanthus. In the survey sites, about 19％ of the areaswere covered by Miscanthus types, and the dry weight of Miscanthus and debris on the ground were 1,164 and 178 g/㎡, respectively. At 350℃ and 400℃, the rise of temperature by Culm type (culms and ears) and Leaf type (leaves and debris) were 90℃ and 82℃, respectively. At 350℃, durning time (BT) of culms-200, ears-200, ears-200, leaves-200 and debris-200 was 0-10’30”, 0-07’40”, 0-04’20”and 0-02’40”, and that at 400℃ was 0-01’20”, 0-00’50” 0-00’35”and 0-00’30”, respectively. BT was shorter at higher temperatures, and BT of Leaf type was shorter than that of Culm type. The amount of samples consumed was as follows: Culm type (culms-200 and ears-200) was 14.6g and 12.6g more than Leaf type (leaves-200 and debris-200) at 350℃ and 400℃, respectively. The total amount of combustion-heat (TACH) of samples was 5,859.7 kcal. The amount of mean combustion-heat generated from sample at 350℃ and 400℃ differed little: 727.6 kcal (24.9％) at 350℃ and 737.3 kcal (26.0％) at 400℃.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.644-653
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• 2002

Sizes of coastal squid jogging boats, their light source output for fishing lamps and daily catch data were collected, for a purpose of evaluating factors on fishing boats, which affect to the squid catch, from four fishing ports (Hakodate, Sado Island, Noto and Tsushima) in Japan. The catch amount was increased as boat sizes and their light source output of fishing lamps were increased up to 100$\~$200 kW class and 11$\~$15 gross tonnage class. The relationship between catch per unit efforts y (box/machine/day), gross tonnage x_{1}, (GT) and light source output for fishing lamps x_2 (kW) is expressed as following formula; $y=4.091+0.18x_1+0.0019x_2$. Thus, 0.1819 boxes of squid catch can be expected, when light source output for fishing lamps increases for 1 kW $(x_2{\leq}200)$ and boat size 1 GT ($x_1\leq15$). It is considered that the boat size which created a shadow area under the jigging boat, is important factor affecting to catch amount, Because larger shadow area created by bigger boat has a possibility to let more squid stay there.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.368-377
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• 2014

Small yellow croaker is one of the important stocks in Korean waters. In this study, we conducted sea trials to estimate optimum height of a drift gill net for effective fishing of small yellow croaker. In the trial using existing net which has 9.2m in height, there was 22 species (1,180 fishes, 99.9kg) caught. The catch (in individuals) of small yellow croaker, especially larger fishes (over 22cm in FL), was higher as part of net height is higher, while the number of species bycaught and the catch of those species were higher as part of net height is lower. In the trial using extension net which has 18.4m in height, there was 27 species (2,030 fishes, 151.7kg). It showed same pattern with existing net in the section I to III, however, in the section IV which is over 13.8m of net height, the catch sharply decreased. The number of species bycaught and the catch of those species using extension net were also same as results using existing net. It showed that section III (9.2-13.8m) where is upper-middle part of the net has caught most of catch and large fishes having over 22cm in length. Through these results, it is judged that the setting depth of the net where is 4.6-13.8m above the sea bottom is the best to reduce bycatch and catch much more large size fishes, and the catch per net is proportional to filtering area of net. Therefore the Fisheries Resource Management Act (the clause 1, article 10) on the amount of usage for offshore drift gill net need to be considered not only length of a net but also net height.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.2
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• pp.105-120
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• 2019

The species composition and abundance variations of fishery resources in the adjacent marine ranching area, Tongyeong, Korea, were investigated by shrimp trawl, gill net, and longline during the period of July, September, and October in 2016. During the study period, the total catch were 8,522.9 kg with 34 species from the shrimp trawl, 32 species from the gill net, and nine species from the longline. The dominant species were different by gear, which were Hypodytes rubripinnis and Parapercis sexfasciata in the shrimp trawl, Platycephalus indicus and Raja kenojei in the gill net, and Conger myriaster and Scomber Japonicus in the longline. In terms of spatial distribution, Yongchodo showed the highest total catch in number as well as of in weight while Jukdo showed the lowest total catch in number and Bijindo showed the lowest total catch in weight. The amount of demersal fish resources in the survey area estimated as 301 ha, was 99,396 individuals which was converted to be 8,552.9 kg. The amount of demersal fish resources by gear were of trawling area, which area is 127 ha, were 76,251 and 3,489.5 kg, 74 ha in the gill net and longline survey area was 16,213 and 3,457.3 kg, and the other 100 ha area was 6,932 and 1,606.1 kg. In this study, the minimum resources for demersal fish is 61,687 and 4,265.2 kg, and the maximum is 149,439 and 14,197.9 kg.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.1
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• pp.1-10
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• 2006

Present study was conducted to improve the spring frame net trap for conger eel, Conger myriaster which prevents by-catch and protects immature fish. A series of comparative fishing experiment was carried out in water off the south-east coast of Korea from Nov. 2004 to Jul. 2005. And analyzed the amount of catch, by-catch rate, and CPUE, etc. of experimental traps which were the spring frame net traps, sorted four types of flappers. And the compared gear was a plastic conger eel pot. The conclusions were as follows. By-catch rates of spring frame net trap with the compressed flapper bound by nylon mono-filament was about 0-3%. CPUE of spring frame net trap with the compressed flapper was about 50-60% lower than that of traditional and plastic pot. And in case of conger eel that the total length is over 350mm, CPUE was little different on each type of flapper of every mesh size.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.15 no.2
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• pp.95-100
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• 1979

In fishing with the anchovy boat seine, it is required to haul up the bag net without injuring anchovy body. Not to injure anchovy body, the bag net is operated with 30 to 34 crews in the traditional method. With a view point of decreasing crews, the authors tried to operate the bag net with side drum winch and derrick boom. Side drum winch was installed beside the engine casing and it was operated by the main engine through the belt, pulley and bevel gear. The derrick boom, 7 meters long, was installed above the working deck which is located in the stern of the common boat seiner. Three single blocks are attached to the boom, each 2 meters apart from the top. A hook was attached to the free end of the block line for hooking up the bolch line which attached inside the bag net especially prepared for the purpose. The hauling end of the block line was induced to the side drum winch for hauling up the bag net. By using this mechanism, the bag net was hauled up with peeling the bag net just like in the traditional method. So the following results are found. (1) No injury of anchovy body was found in the process of hauling up. (2) The bag net can be operated by mere 14 crews. (3) Duration, spent in hauling up the bag net, was almost the same when the catch are a little amount, and less duration was needed by the experimented method than the traditional one when the catch are a large amount. the bag net. By using this mechanism, the bag net was hauled up with peeling the bag net just like in the traditional method. So the following results are found. (1) No injury of anchovy body was found in the process of hauling up. (2) The bag net can be operated by mere 14 crews. (3) Duration, spent in hauling up the bag net, was almost the same when the catch are a little amount, and less duration was needed by the experimented method than the traditional one when the catch are a large amount.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.1
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• pp.27-36
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• 2024

The towing distance, which is speed over the ground, and the water flow quantity, which is speed through the water, were used when estimating the amount of Metapenaeus joyneri resources that rose to the surface at night using the swept area method in order to compare and analyze the difference. It was conducted using a shrimp dredge, trial fishing gear for catching Metapenaeus joyneri. Catch during the entire survey period was 188.9 kg. Monthly catch ranged from 3.1 to 109.2 kg, highest in June and lowest in September. The swept volume calculated using the speed over the ground was about 13% higher than using the speed through the water. Metapenaeus joyneri resources estimated using the towing distance ranged from 320.1 to 14,649.8 kg. Resources estimated using the water flow quantity ranged from 278.5 to 12,886.3 kg. Therefore, the amount of Metapenaeus joyneri resources estimated using the speed over the ground was about 14% higher than the method using the speed through the water, indicating that the amount of resources was overestimated.