• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.4
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• pp.299-315
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• 2020

Tuna fisheries were applied to an integrated ecosystem-based fishery risk assessment method using indexes of target species status, inhabited species in a target ecosystem, habitat quality and socio-economic benefit of affected fisheries. This study suggested more effective and efficient management measures to break away from traditional management methods, such as limitation of catch and fishing effort. The results presented that the objective risk index (ORI_S) on sustainability of bigeye and yellowfin tunas by purse seine fishery was estimated high due to the high catch ratio of small fishes. The ORIs of biodiversity (ORI_B) and habitat quality (ORI_H) of purse seine fishery were also estimated at a high level from using fish-aggregating devices (FAD). However, due to skipjack tuna's high catches, the ORI of socio-economic benefit (ORI_E) was estimated at a very low level. Due to the high bycatch rate, ORI_B was high, and ORI_S and ORI_H were evaluated at a low level in longline fishery. Due to strengthern of fishing restrictions and increase of fishing costs, the ORI_E was assessed to be very high. The ecosystem risk index (ERI) for two tuna fisheries was assessed low, but the overall FAD management by purse seine fishery is necessary at the ecosystem level.

• The Journal of Fisheries Business Administration
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• v.53 no.2
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• pp.1-20
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• 2022

This study is aimed to analyze fishermen's perception and the economic feasibility of inland waters ranching project on the branches of Geum River. Analysis of fishermen's perception on the branches of Geum River showed that fishermen had an affirmative response on the inland freshwater ranching project related issues such as fisheries resources enhancement, necessity of project, economic achievement as so on. The model of inland waters ranching project on the branches of Geum River is designed to fisheries resources enhancement, habitat compositiom, ecology tours, use and management of resources. The results of the economic feasibility of inland waters ranching project on the branches of Geum River were internal rate of return (IRR) was 18.43%, a benefit-cost ratio was shown to be 1.54, net present value (NPV) was 4,929 thousand won, which indicates the economic feasibility of inland waters ranching project.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.267-280
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• 2019

Adaptive Management (AM) is one of the best available approaches for managing natural resources in the presence of uncertainty. In spite of the limitations, AM has been widely applied in nature resource management policies and plans internationally, while application of AM in nature resource management in Korea is limitedly used. Accordingly, this study reviews application of AM in nature resource management research in Korea with respect to its definitions, procedures, impediments and considerations. The present study also reviews recent ecological modelling studies which is an essential component of AM approach. Finally, management of artificial sea forest, coastal wetlands and fisheries are suggested as the recommended fields to adopt AM.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.197-208
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• 2016

The WCPFC CMMs related to tropical tunas have been strongly restricting fishing capacity and operating activities of main fisheries, especially purse seine fishery. In terms of changes in fishing trend by implementing relevant measures of FAD set, the number of FAD set by Korean purse seine fleet showed a decreasing pattern with the lowest level of FAD set proportion among major distant water fishing nations. With regards to the FAD closure, there was no significant change in fishing effort but a drop in catch, especially bigeye tuna during the period of FAD closure. Moreover, it showed closely similar trends between the number of FAD set and bigeye tuna catch. In terms of measures related to the high sea area including a ban on fishing on the HSP and limitation of fishing days on the high sea by flag state, proportions of catch and effort on the high sea had sharply declined after implementing those measures. As relevant measures are expected to be strengthened, it should pay attention to change of coastal nations policies and focus on improving fishing efficiency of unassociated school set with multi-pronged efforts.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.760-767
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• 2015

First annulus formation and age determination of otoliths were examined for chub mackerel Scomber japonicus collected in Korean waters over the one year from January to December in 2009. Translucent zone was regarded as an annual mark. Age interpretation criteria was based on the data of the number of translucent zone, capture date, and edge type of the otolith, assuming the nominal birthday to be 1 January. Monthly changes in mean marginal index indicated that translucent zone was formed once a year, mainly in June. The otolith of 0-ring group was detected comparing the progression by month of the smaller fish length, appearing to be a single first opaque zone. The average distance from the core to the first translucent zone was ~1.77 mm, provided as supplementary information to increase ageing accuracy. The ageing criteria for chub mackerel was made to determine correct year-class with the purpose of effective stock assessment. This method using nominal birthdate and edge type analysis could estimate age of fish closer to the true age than purely counting the number of translucent zone on a whole otolith.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.851-855
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• 2013

To determine the status of sunfish fishery, fishing places, body size, weight, etc. were investigated from 2010 to 2012 in Busan Cooperative Fish Market. Most of the sunfish were caught by large purse seine around Jeju island, and the fishing ground of sunfish were reached from Heuksando in the southern Yellow Sea to Guryongpo in the southern East Sea. The range of total length (TL) of the sunfish caught by purse seine was 55-271 cm, and the estimated length-weight relationship was $BW=8E-06TL^{3.3797}$. From the relationship, the weight of 50 cm in total length was estimated to be ca. 4 kg, TL 100 cm was ca 46 kg, TL 200 cm was ca 478 kg, and TL 271 cm was estimated to be 1,336 kg.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.445-455
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• 2021

We aimed to study the structure of the zooplankton community in the Southern Sea of the Republic of Korea. Zooplankton samples were collected in February (winter), May (spring), August (summer), and November (autumn) of 2020. The zooplankton collected belonged to a total of 166 taxa and 12 phyla, including some unidentified individuals and those from upper taxa. The number of taxa collected were the highest in winter at 117, and the lowest in May at 93. The dominant taxa were Oikopleura spp. in the winter, Gastropoda larvae in the spring, and Paracalanus parvus s.l. in the summer and autumn. The community structure of the zooplankton was clearly distinguishable between the seasons. The mean density of zooplankton was the highest in autumn and the lowest in summer (576,039 and 313,000 individuals/1,000 m³, respectively). Based on the analysis of relationships between the density of the six major taxa and environmental factors, a significant correlation (P<0.05) between the four taxa and environmental factors was found. Therefore, in order to understand changes in the zooplankton community, quantitative and qualitative investigations of biological factors as well as physical factors should be conducted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.64-72
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• 2021

The feeding habits of the Japanese jack mackerel Trachurus japonicus were studied in the Southern Sea of the Republic of Korea. To assess the effects of season, sampling was conducted in February (winter), May (spring), and August (summer), 2020. The total length of each fish was measured in 1 cm intervals. Diet composition showed the highest species diversity during winter. Diet composition changed from copepods to euphausiids as the total length of jack mackerel increased, except during winter. The most important seasonal prey were copepods in winter and summer and euphausiids in spring. Species diversity of the zooplankton community structure was highest in winter. Among the zooplankton communities, copepods were dominant in all seasons. Species with a high electivity index in all seasons were relatively large zooplankton of ≥2 mm. Jack mackerel had ontogenetic diet change, exhibited diet selectivity depending on size, and its feeding habits were affected by the zooplankton community structure.

• The Journal of Fisheries Business Administration
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• v.30 no.1
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• pp.97-118
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• 1999

This study discussed the international reorganization of fisheries in the East China Sea and the Yellow Sea, for the cases of Korea, China and Japan, through the fishery competition and the division of sea areas and resources. In these sea areas, each country has done mutual operation, which causes the fishery competition and controls fishery development. Besides, Exclusive Economic Zon(EEZ) established in 1996 resulted in the prominent changes of fishery development as well as fishery relationship among each country, demands reorganization of fisheries. New fishery order in these sea areas is controlled by BEZ system. The fishery reorganization according to EEZ is a common issue of each country and it also includes the importance of mutual fishery agreement. Resources of fisheries could be used continuously under reasonable management. Each country should consider the stability and existence of fisheries in the international viewpoint. At this point of time, those should be considered such as adjustment of interests according to the division of sea areas, establishment of resource management system and insurance of fishery management, for the subject of fishery reorganization.

• Journal of Fisheries and Marine Sciences Education
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• v.9 no.2
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• pp.121-148
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• 1997

The Japanese fishery management system has been established on the basis of various experience accumulated over many years. The fishery management system in Japan, one of the oldest fishery management systems in the world, is aimed at ensuring comprehensive utilization of the water surface and developing fishery productivity, by giving protection of the breeding environment of aquatic animals and plants, enabling the appropriate use of fishery grounds, preventing and solving disputes over fishery grounds and making other fishery adjustments. Japanese Fishery Law has been changed largely into (1) The Feudal Era(to 1900), (2) The Oldest Fishey Law(1901~48), (3) Current Fishery Law(1949 to present). Japanese fishery legislation is designed as a single package combining coastal, offshore and distant-water fisheries. During the period of the old fishery law, numerous conflicts arose over the joint use of fishing grounds and fish stocks. Such conflicts occurred among users of the same gear as well as between users of different gears or of different sizes of fishing craft. Large scale conflict sometime occurred between neighbouring fishing communities due to a lack of fairness in principle and coordination in practice. Therefore, the new fishery law enacted in 1949. This law was designed primarily to realize the most effective and rational use of fishing grounds and fishery resources, the basic philosophy being that, through democratic organization by fishermen themselves, productivity would be stimulated and incomes and living standards eventually improved. Nowadays, Community Based Fisheries Management through democratic organization by fishermen themselves have to enforce at coastal fisheries. This Community Based Fisheries Management manage to fishery resources by fishermen themselves and harvest in collaboration with that resources. Therefore, this paper is intended to briefly to describe the entire system and the historical development of Japanese fishery legislation in order to assist in reform of our country fisheries management regime.