• 수산해양기술연구
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• 제57권3호
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• pp.185-193
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• 2021

This study was conducted to evaluate the performance of the octopus pot according to mesh sizes. Entering behavior of Octopus minor and bait (Macrophthalmus japonicus) escape rate on the mesh sizes of the pots were investigated for six times in indoor tank. The sea trials for evaluating the performance of Octopus minor pot to different mesh sizes (22, 20 and 18 mm) were conducted for six times from 2017 to 2018 in the coastal sea of Deukyang Bay, the Republic of Korea. Behavior patterns of contact pot to leaved pot were more frequent than contact pot to bait search. When the octopus contacted to the pot, there was no clear search behavior to distinguish the mesh sizes. Total catch of 46% was accounted for 18 mm pots, followed by 34% at 20 mm and 20% at 22 mm (P < 0.05). Catch per unit effort was calculated as 30 g/pot at 22 mm, 44 g/pot at 20 mm and 59 g/pot at 18 mm. As a result of evaluating 50% selection of mantle length and weight on the mesh sizes, mantle length (mm) and weight (g) were 84.6 and 147.8 in 22 mm, followed by 20 and 18 mm.

• 한국수산과학회지
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• 제52권6호
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• pp.685-695
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• 2019

To assess the state of Todarodes pacificus fisheries, we examined changes in major fishing and ecological characteristics by comparing jigging fishery data between high (HCLP, 1996-2000) and low (LCLP, 2013-2017) catch level periods. The peak catch occurred in October during the HCLP compared with December during the LCLP. The average catch per unit effort was higher during the HCLP (1.3 tons/jigging vessel) than LCLP (1.0 ton/jigging vessel). During the HCLP, fishing grounds were highly concentrated in the southwestern East Sea and Yamato bank, whereas during the LCLP, the distribution of grounds extended to the South Sea, West Sea, and northern East Sea (near Russian waters) at a low density. Water temperatures in the main fishing ground in the southwestern East Sea were higher at 0, 50, and 100 m depths during the LCLP than HCLP. Meanwhile, the average mantle length of catches decreased from 23.5 cm during the HCLP to 22.21 cm during the LCLP. The mantle length at 50% maturity also decreased between the two periods from 22.06 (HCLP) to 18.77 cm (LCLP). These findings will help guide future management strategies for T. pacificus.

• 수산해양교육연구
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• 제26권1호
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• pp.108-125
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• 2014

Although South Korea had managed fishery resources based on elements included in the fishery like fisheries licence, after agreeing on UN Convention on the law in 1999, it became inevitable to adopt TAC that regulates yield. Therefore, currently operating an indecisive system by maintaining the fisheries license system while applying TAC only to some fisheries. However, it became imperative to find ways to improve the current system as it dose not solve problems such as decrease of fishery resources and catch per unit effort, excessive input of fishing boats, rising costs for fishery management, and shortage of fishery population. For those reasons, it is time to review ITQs, which is recognized globally as the most innovative fisheries management system. To adopt the ITQs, it seems necessary to compare how the fisheries act of New Zealand which is currently most successfully operated and Fisheries Resources Management Act of Korea. To do so, in this study, the provisions on TAC of the two countries are compared to analyze the institutional necessity for Korea to adopt ITQs. The following conclusions have been made : First, it will be necessary to gradually expand the species and fisheries for which TAC is enforced, and accumulate correct data on fisheries resources. Second, while forcing traders to obtain license as well, the species and quantity of traded fisheries must be reported separately for cross-checking with the catch reported by the fisheries. Third, the number of observers must be increased and report the species and quantity of the catch to person in charge at the relevant port, and observers must check the report before disembarkation. Fourth, penalty for violating Fisheries resources management act must be enhanced, especially regarding false report of fishery activities and catch.

• 한국수산과학회지
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• 제47권6호
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• pp.1037-1054
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• 2014

In this study, the status of coastal fisheries was examined based on the catch and number of fishing vessels of coastal fisheries in Korea. Comparing the status on coastal fisheries of the East Sea, Yellow Sea and South Sea in Korea, scientific evidence was made for fisheries management on coastal fisheries based on characteristics of each sea area. From 1990 to 2011, the catch of coastal fisheries in Korean waters ranged from 150,000 mt to 230,000 mt, with an average of 190,000 mt, and it accounted for 15% in average of total catch fished in adjacent waters of Korea. In order of catch by coastal fisheries, gillnet (36.7%) was the primary fishery, followed by coastal complex (24.7%), stow net (18.3%), trap (12.9%), lift net (3.9%), purse seine (3.0%) and beam trawl (0.4%) fisheries. In order of catch by species, anchovy (15.0%) had the largest proportion of total catch, followed by common squid (10.3%), akiami paste shrimp (5.2%), blue crab (3.9%) and octopus (3.7%). Of the average catch by sea area from 1990 to 2011, Yellow Sea, South Sea and East Sea were 37.4%, 34.6% and 28.0%, respectively. Since 2000s, however, the average catch of South Sea has accounted for the largest proportion. The number of permitted fishing vessels involved in 8 coastal fisheries was 55,336 vessels in average from 1997 to 2011. The number of vessels was about 47,000 vessels in 1997, and increased to 61,300 vessels until 2000, then has decreased to 44,000 vessels operating in 2011. In order of the number of permitted fishing vessels by fisheries, complex (52.4%) took the first place, followed by gillnet (31.5%), trap (13.4%), stow net (0.8%), beam trawl (0.8%), purse seine (0.6%), lift net (0.4%) and seine net (0.0%). In order of the number of permitted fishing vessels by sea area, South Sea (29,994 vessels) took the first place, followed by Yellow Sea (18,185 vessels) and East Sea (7,158 vessels). In order of the catch per unit effort (CPUE, mt/vessels) which was analyzed using catch and number of vessels in average by fishery, stow net is the highest followed by lift net, trap, purse seine, gill net, beam trawl and complex fisheries. In particular, the CPUE of complex and gill net fisheries, which accounted for the largest number of vessels were 4.0 mt/vessels and 1.6 mt/vessels, respectively. Since those are too low relative to other fisheries, it was judged to need systematical management on both fisheries.

• 응용통계연구
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• 제28권5호
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• pp.847-858
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• 2015

남극해에서는 우리나라를 포함한 연안 강대국들의 원양어업이 활발히 성행하고 있다. 주인 없는 남극해의 생태계를 보호하기 위해 조업 국가들은 남극해양생물자원보존위원회를 만들고 협약을 맺어 일정한 어획량만 조업하고 금지기간과 금지구역을 설정하여 불법조업을 방지하고 있다. 남극해에서 조업하는 어종 중의 하나가 이빨고기(tooth fish)인데 비싼 값 때문에 불법조업이 있는 경우가 많다. 한 배의 조업성과는 CPUE(catch per unit effort)로 나타낼 수 있고, 한 지역에서 조업한 배들의 CPUE는 단일 또는 혼합 극단분포 형태를 가진다. 단일 극단분포일 경우 이상점 탐색은 상위 백분위수를 이용하면 된다. 본 논문은 자료가 혼합 극단분포인 경우 이상점 탐색을 위한 통계적 방법을 연구하고자 한다. 본 연구에서는 자료에 적합한 혼합 극단분포 모형을 EM 알고리즘으로 추정한 후 로그 가능도함수 값을 이용하거나 사후 확률을 이용한 이상점 탐색 알고리즘을 제안한다. 이 방법을 남극해 조업 데이터에 적용하여 시뮬레이션 한 결과 통계적 방법 적용의 가능성을 보여주었다.

• 수산해양기술연구
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• 제12권2호
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• pp.43-47
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• 1976

The large two-boat trawl is of importance in Korean fishery. It occupied 12.8% of total catches in 1974. The author analysed the reports of six large two-boat trawlers operated at the Yellow Sea and the East China Sea, in the term from September 1975 to March 1976. The results obtained are as follows; (1) 1,710 of total hauls are operated in the term, and the total catches amounted 559, 181kg. Then, 325kg of catch per unit effort (C. P. U. E) are obtained. The catches are specified into 28% of soles, 12% of shrimp, 8% of yellow corvenia, hair tail, kang-dari, and the rest of miscellanous fishes. (2) C. P. U. E. of the southern sectors of the Soheaksan Is. represented superior catches to compared with others sectors. (3) The monthly variation of C. P. U. E. between sea eel and yellow corvenia revealed positive correlation, whereas between sole and shlimp, between hair tail and rays revealed negative correlation respectively.

• 수산해양기술연구
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• 제46권4호
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• pp.476-486
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• 2010

Fishing efficiency of a trawl vessel can be enhanced by increasing the swept area per unit time, which can be attained either by increasing the mouth size of the net, or by increasing the towing speed. To improve fishing and fuel efficiency of trawl vessels targeting fishes of greater mobility, in which the towing speed is more critical in determining fishing efficiency, we conducted a series of model tests to evaluate the performance of the newly-designed nozzle propeller before installing it in a trawl vessel to verify its towing speed and fuel efficiency in the sea. By conducting further model tests in the experimental basin, we redesigned the propeller of stern trawler to improve the resistance and propulsion performance. Through actual fishing operations, we evaluated the improvement in fuel and fishing efficiency by installing the new nozzle propeller. The trawling speed increased by 0.6kts at the same engine power (RPM), while the engine margin increased by more than 20%. The increased towing speed by installing the redesigned propeller is expected to enhance fishing performance through increasing the number of hauling- and casting operations per unit times, while shortening the towing duration. Analysis of the Catch-Per-Unit-Effort (CPUE) data indicated that the mean CPUE of trawl fishery increased from 3.04kg/m in year 2007 to 6.15kg/m in year 2008, confirming enhanced fishing efficiency by adopting the redesigned propeller.

• 수산해양기술연구
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• 제44권3호
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• pp.194-206
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• 2008

This study standardized catch per unit effort(CPUE) of the Korean longline fishery, which has been used to assess the status of stock as an index of abundance, for bigeye and yellowfin tunas in the Indian Ocean. The Generalized Linear Model(GLM) was used to analyze the fishery data, which were catch in number and effort data collected each month from 1971 to 2007 by $5\;{\times}\;5$ degree of latitude and longitude. Explanatory variables for the GLM analysis were year, month, fishing area, number of hooks between floats(HBF), and environment factors. The HBF was divided into three classes while the area was divided into eight subareas. Although sea surface temperature(SST) and southern oscillation index(SOI) were considered as environmental factors, only SST was used to build a model based on statistical significance. Standardized CPUE for yellowfin tuna showed a declining trend, while nominal CPUE for the species showed an increasing trend.

• 한국수산과학회지
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• 제44권4호
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• pp.397-402
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• 2011

We surveyed the bycatch and discard of the shrimp-pot fishery in Hokkaido, Japan, three times during the major fishing period in September 2005. The surveyed catches were analyzed to separate bycatch, discard, and landings. To analyze bycatch and discard, we randomly selected 2 shrimp pots from each of 7 sets, for a total of 14 pots per survey. The total bycatch and discards from the rest of the shrimp pots were also analyzed in each survey. The total catch averaged 12 species. Coonstripe and pink shrimp catches averaged 74.7 kg/haul and 12.7 kg/haul, respectively. The weight of the bycatch averaged 33.4 kg/haul. The bycatch consisted mainly of snail fishes(5.1%), brittle stars(5.0%), and short-spined sea urchins(4.1%). Our analysis showed that the ratio of discard was 0.38, the rate of the discard was 27.4%, and the discard per unit effort was 33.4 kg/haul. The Hokkaido shrimp-pot fishermen discarded all of the bycatch except shrimps. Hence, the weight of the bycatch was equal to the weight of the discard. Our results comprise preliminary data that can be used to find ways to reduce bycatch and discard in the shrimp-pot fishery.

• 수산해양기술연구
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• 제40권4호
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• pp.282-294
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• 2004

아르헨티나 짧은지느러미오징어는 1993년에 99,000톤에서 1994년 56,600톤으로 감소하고 1996년에는 78,600톤에서 1997년 130,300톤으로 다시 증가하였다. 어획량의 급감 및 급증한 1993~1994년과 1996~1997년의 성어기인 3~5월의 풍도 원인을 구명하기 위하여 아르헨티나 짧은지느러미오징어의 수온 변동에 따른 풍도 변화를 분석하였다. 호황을 보였던 해인 1993년과 1997년은 성어기에 주로 50$^{\circ}$~51$^{\circ}$S간 해역에서 주어장이 형성되었고, 불황을 보였던 1994년과 1996년에는 50$^{\circ}$S이북에서 성어기 어장이 형성되었으며 포클랜드 어장의 평균수온은 3월 10~11$^{\circ}$C, 4~5월은 9$^{\circ}$C로 평균 등온선이 형성되는 위치에 따라 어황이 변동하는 것으로 나타났다. 아르헨티나 짧은지느러미오징어의 높은 단위노력 당어획량(kg/line) 및 어획량은 어장이 포클랜드 해류의 영향을 받지 않은 1993년 및 1997년은 호황을 보였고, 북상하는 포클랜드 해류의 영향을 받은 1994년 및 1996년에는 급격히 감소되어 불황을 보였다.