• Ocean and Polar Research
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• v.31 no.2
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• pp.157-165
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• 2009

The study examined overuse of the fishery resource. Influence of fishing activity was estimated by application of Schaefer model's. Fishing efforts that produced the maximum sustainable yield were determined in the model, allowing the effect of overfishing to be assessed. In the model, a wide variety of fish species as well as crustaceans and shellfish were susceptible to overfishing, while mollusks were not. Overfishing by modern techniques exacted a greater toll than more traditional methods. The results of the modeling study suggest that the 'Buy bag' input-control system of fisheries resource management warrants consideration, as does modernization, expansion and strengthening of self-control management of the fishery resource. Finally, more effective efforts in dissemination of policy information and education concerning the fishery resource are needed.

• 한국수산학회:학술대회논문집
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• 2005.05a
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• pp.21-23
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• 2005

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.1
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• pp.25-46
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• 2003

Marine recreational fishing is one of the most popular outdoor leisures and the number of people who are participating is sharply increasing more and more because of the increasement of their income and demand for marine leisure. However our ecosystem is inevitably facing marine environmental deterioration and overfishing. That is because marine recreational fisheries resources are common property resources which can be catched by anyone not willing to pay for them except their private costs as commercial fisheries. Also fisheries resources unlike other resources are renewable resources and have a critical zone. That is, having a possibility of severe depletion may result from high discount rates used by private exploiters. This paper is focused on that marine recreational fishing license system which is adopted in most advanced countries such as Canada and U.S. and included in deterioration. And money obtained by license fee should be spent for more improvement fishing culture and welfare for marine recreational fishers.This system can lower the high rates of discount and be useful to become a sustainable marine recreational fishing industry.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.5
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• pp.1009-1019
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• 2013

본 연구는 어업자원이 건강한 상태에 있는지 아니면 남획된 상태에 있는지를 판단하고, 현재 어업활동이 과도한지 아닌지를 판단하기 위한 간단하고 실용적인 방법을 개발하였다. 자원평가를 수행시에는 고가의 자료와 고도의 기술력이 요구되는 어려움이 있는데, 특히 소규모 어업과 다종어업에서 어려움이 더욱 심하다. 본 연구에서 개발된 방법은 어업자원의 구체적인 상태와 어업활동의 객관적인 상태를 고려해서 어업자원을 보존하고 어업활동을 규제할 수 있는 실용적이고 신뢰할 수 있는 방법이다. 예를 들어, 자원량과 어획사망률을 추정하는데 필요한 자료가 없거나, 추정할 수있는 과학적 능력이 부족한 경우에는, 자원량을 대용해서 단위노력당어획량을 사용하고 어획사망률을 대용해서 어획노력량 자료를 사용할 수 있다. 본 연구에서 제시한 방법의 실현가능성과 유용성을 입증하기 위하여, 복수어종으로 집계된 어획량과 어획노력량 만으로 된 경우나 또는 개체군 특성치 정보와 체장자료 만이 이용 가능한 경우에 대해 적용하였다. 이 방법은 수산자원의 보존이라는 전지구적 목표를 달성하는데 있어서, 필요한 자원상태와 어업상태를 판단해서 어획활동을 규제하고 조정할 수 있는 유용한 방법이 될 수 있을 것으로 보인다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.942-953
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• 2020

Achieving optimal sustainable yields (i.e., avoiding overfishing and maximizing fishery harvest at the same time) is one of the main objectives in fisheries management. Generally, management reference points (MRPs) such as fishing mortalities (Fmsy, F0.1, Fx%) have been suggested for the purpose. In this study, we intended to suggest MRPs for Korea chub mackerel Scomber japonicus stock, using a stochastic catch-at-age model (SCAA) and evaluate whether the current fishing intensity on the stock is appropriate. We used length frequency and catch-per-unit-effort data on the Korea chub mackerel stock collected from the large purse-seine fishery, and yields landed by all fisheries from years 2000 - 2019. We calculated yield per recruit and spawning potential ratio, and projected spawning stock biomass (SSB) under different fishing mortality, assuming annual recruitments were solely controlled by environmental effects (i.e., steepness of 1.0). Some of our major findings and suggestions were that the overfishing threshold would be F46%; i.e., the fishing mortality in the terminal year, 2019 was 0.257/year, which corresponded to F46%.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.463-464
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• 2000

Skates are one of the most favorite food fishes for Korean people. It is, I think, important to know the biological characteristics of skates for protecting the fishes from the extinction caused by overfishing. Femily Rajidae encompasses about 200 species which is one fourth of elasmobranch fishes, and 11 species known from the Korean waters. But, very few biological characteristics of skates have been known Some of them are shown here and discussed comparing with those of other elasmobranch fishes (sharks and rays) and teleost fishes. (omitted)

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.186-192
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• 2013

Because of the shallow depth of 44 m and large area of wetland in Korea and China, the class I productivity of Yellow Sea is very high (>300 $gC/m^2/year$), which is supporting substantial populations of fish, invertebrates, marine mammals and seabirds. However, the Yellow Sea is a large marine ecosystem which is enclosed by mainland of China and Korean peninsula, so it is vulnerable to external stress such as environmental degradation and overfishing. Recently, since the Fisheries Agreement between Korea and China, overfishing and illegal fishing of China and environmental degradation caused by coastal development in Korea and China have given much stress to the marine ecosystem of Yellow Sea. This article suggests that the major factors of governance are ineffectively responding to the growing demand for exploitation of the Yellow Sea and the international cooperation for establishing network of Yellow Sea governance is urgent.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.3
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• pp.217-223
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• 2018

Overfishing capacity has become a global issue due to over-exploitation of fisheries resources, which result from excessive fishing intensity since the 1980s. In the case of Korea, the fishing effort has been quantified and used as an quantified index of fishing intensity. Fisheries resources of coastal fisheries in the Korean waters of the East Sea tend to decrease productivity due to deterioration in the quality of ecosystem, which result from the excessive overfishing activities according to the development of fishing gear and engine performance of vessels. In order to manage sustainable and reasonable fisheries resources, it is important to understand the fluctuation of biomass and predict the future biomass. Therefore, in this study, we forecasted biomass in the Korean waters of the East Sea for the next two decades (2017~2036) according to the changes in fishing intensity using four fishing effort scenarios; $f_{current}$, $f_{PY}$, $0.5{\times}f_{current}$ and $1.5{\times}f_{current}$. For forecasting biomass in the Korean waters of the East Sea, parameters such as exploitable carrying capacity (ECC), intrinsic rate of natural increase (r) and catchability (q) estimated by maximum entropy (ME) model was utilized and logistic function was used. In addition, coefficient of variation (CV) by the Jackknife re-sampling method was used for estimation of coefficient of variation about exploitable carrying capacity ($CV_{ECC}$). As a result, future biomass can be fluctuated below the $B_{PY}$ level when the current level of fishing effort in 2016 maintains. The results of this study are expected to be utilized as useful data to suggest direction of establishment of fisheries resources management plan for sustainable use of fisheries resources in the future.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.432-439
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• 2013

This study was performed to assess the current stock condition of elkhorn sculpin along the Uljin area in the East Sea of Korea. To assess the state of the stock, yield-per-recruit (YPR) and spawning biomass-perrecruit (SBPR) analyses were performed. Estimates of $F_{max}$ and $F_{0.1}$ were 2.10/year and 0.48/year, respectively, and those of $F_{35%}$ and $F_{40%}$ were 0.66/year and 0.54/year, respectively. Current fishing mortality was estimated at 0.63/year and the current age at first capture was 2.41years. $F_{40%}$ was set as the target reference point of the stock. SBPR at $F_{40%}$ and current SBPR were estimated to be 41.85g and 37.77g, respectively. Estimated FOTY which is the fishing mortality for the overfished threshold yield was 0.49/year. The ratio of SBPR/$SBPR_{MSY}$ was calculated as 0.90 and that of $F/F_{OTY}$ was 1.05. The ratio of $t_c/t_{c\;opt}$ was calculated as 1.15 and that of $F/F_{OTY}$ was 1.17. Therefore, the current stock condition of elkhorn sculpin along the Uljin area of Korea has not been overfished, however, it indicates that a light overfishing is going on this stock.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.1
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• pp.60-66
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• 2017

This study researched the population of ecological characteristics of the goldeyes rockfish Sebasetes thompsoni sampled by gill net in the Ulleungdo area from February 2013 to February 2014 in order to assess the current stock status and provide scientific advice for management implementation. The instantaneous coefficient of total mortality (Z) was 0.78/year and the survival rate (S) was 0.459. The instantaneous coefficient of natural mortality (M) was 0.461/year. Based on the estimates of Z and M, the instantaneous coefficient of fishing mortality (F) was 0.318/year. The age at first capture ($t_c$) was 4.41/years. Current Yield-per-recruit (YPR) was 30.83 g, and fishing mortality at maximum YPR ($F_{max}$) and fishing mortality corresponding to 10% of the maximum slope in YPR curve ($F_{0.1}$) were 3.257/year and 0.673/year, respectively. $F_{35%}$ and $F_{40%}$, indicating fishing mortalities at 35% and 40% of maximum Spawning biomass-per-recruit (SBPR), were 0.619/year and 0.509/year, respectively. Based on the biological reference points, fishing mortality at overfished threshold yield ($F_{OTY}$) was calculated as 0.509/year. Current $SBPR/SBPR_{MSY}$ was 1.313 above 1.0, which means 'not overfishe,' while current $F/F_{OTY}$ was 0.629 below 1.0, which indicates 'not overfishing.' In conclusion, the current status of goldeyes rockfish was located in green zone (i.e., not overfished and not overfishing) according to the revised Kobe plot.