• 수산해양기술연구
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• 제34권2호
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• pp.105-116
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• 1998

This paper, examines the relationship between water temperatures and fishing conditions of common squid by the squid angling fishery from June to September in 1993-1995. The condition of the common squid fishing largely depended on the fluctuation of water temperature in the coastal area of Gampo. Monthly mean water temperatures during June m September in 1993 and 1994 were relatively higher than those in 1995 in Gampo area. But the values between July and August in 1995 were about 5$^{\circ}C$ lower than those in 1993 and 1995. Coefficients of variation (CV) of water temperature showed the lowest value during July ~ September in 1993, however, the highest value was observed in July and August in 1994. Catch per unit effort (CPUE ; kg/angling) showed a peak with 73.7kg in 1993 when the CV was low. On the other hand, the lowest CPUE of 39.6kg was observed in 1994 when the CV was high. It was concluded that the high stability of water temperatures and the weak strength of cold water have caused the good fishing conditions of common squid.

• 한국해양바이오학회지
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• 제3권1호
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• pp.31-37
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• 2008

Off the 1,572 km long coastline of Namibia lies known as the Benguela upwelling system, a very rich source of marine life supporting traditional and modern forms of fishery. Commercial fishing and fish processing is one of the fastest-growing sectors of the Namibian economy in terms of employment, export earnings, and contribution to GDP. The fishing industry has grown to the extent that it is currently Namibia's second biggest export earner of foreign currency after mining (90% of national output is marketed for export). In 2005, Namibia harvested about 552,164 tonnes of fish. The final value of processed products (export value) that year was around US$ 376.0 million. Besides the marine captured fisheries, Namibia also has a small but vibrant aquaculture sector. Inland captured fisheries exist in the north-east and north-west of Namibia where as commercial freshwater aquaculture of tilapia and catfish is also undertaken. The inland fisheries are mainly subsistence based and typically labour intensive, with low catch per unit effort. However the subsistence fisheries from these regions play a significant role in the lives of rural community. The domestic market for marine fish products is extremely limited due to the small size of the population (2 million). The fishing industry is a source of considerable employment for many Namibians. Huge potential to increase production exists in Namibia, unpolluted high quality marine waters, high natural primary productivity of the seawater, availability of inexpensive fish by-products from established fish processing sector for inclusion in wet aqua-feeds and well-established processing, packaging and marketing systems due to the marine capture fisheries that can be adopted for aquaculture purpose.

• 한국해양공학회지
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• 제15권2호
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• pp.130-134
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• 2001

Recently environmental pollution at sea becomes serious, so every governmental organization makes its effort to solve this problem. Combustible ocean wastes as of ropes, fishing nets, and tires are usually highly polymerized compound materials. The problem of ocean waste treatment can be solved by using the pyrolysis method. Pyrolysis characteristics of ocean waste was examined to get the basic data for the production system of fuel from the ocean waste. Thermogravimetric experiment showed that residual mass rate decreases as the velocity of temperature-rising becomes lower. The pyrolysis of waste rope and fishing net occurs at 300~450$^{\circ}C $ and the waste tire does at 350~450$^{\circ}C $. Pyrolysis time is estimated about 15 to 20 minutes in the temperature range when lively act of pyrolysis temperature reached.

• Fisheries and Aquatic Sciences
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• 제25권9호
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• pp.473-488
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• 2022

To have a better understanding of the impact of the PETRONAS oil and gas platform on commercial fisheries activities, Universiti Malaysia Terengganu (UMT) examined two approaches which are data collection from satellite and data collection from fishermen and anglers. By profiling the anglers who utilize reefed oil and gas structures for fishing, it can determine if the design and location of the reef platforms will benefit or negatively impacts those anglers and fisherman. Furthermore, this assessment will be contributing to the knowledge regarding the value of offshore oil and gas platforms as fisheries resources. Collectively, the apparent fishing activity data included, combined with the findings in the reefing viability index will help to inform PETRONAS's future decommissioning decisions and may help determine if the design and proposed locations for future rigs-to-reefs candidates would benefit commercial fishing groups, further qualifying them as appropriate artificial reef candidates. The method applied in this study is approaching by using a data satellite known as Google's Global Fishing Watch technology, which is one of the applications to measure commercial fishing efforts around the globe. The apparent commercial fishing effort around the selected twelve PETRONAS platforms was analyzed from January 2012 to December 2018. Using the data collection from fishermen which is the total estimation of commercial fish value cost (in Malaysia ringgit, MYR [RM]) in Peninsular Malaysia Asset, Sabah Asset, and Sarawak Operation region. The data were extracted every month from 2016 to 2018 from the National Oceanic and Atmospheric Administration database. Most of the selected platforms that show a high frequency of vessels around the year are platform KP-A, platform BG-A and platform PL-B. The estimated values of commercial fishes varied between platforms, with ranged from RM 10,209.92 to RM 89,023.78. Thus, platforms with high commercial fish value are selected for reefing in-situ and will serve multi-purposes and benefit the locals as well as the country. The current study has successfully assessed the potential reefing area of the Malaysian offshore environment with greater representativeness and this paper focused on its potential as a new fishing ground.

• 수산해양기술연구
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• 제33권2호
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• pp.90-96
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• 1997

민꽃게를 대상으로 하는 통발 어구에 관한 지금까지의 연구가 통발의 형상, 입구의 수 등 주로 강조적인 측면을 개선하는데 주력하였을 뿐 민꽃게의 은신행동 등 민꽃게 자체의 기본적 습성을 충분히 이용하였다고는 볼 수 없고, 그물 통발이 가지는 민꽃게 수입 성능상의 한계점을 근본적으로 개선하지는 못하였다고 생각되었기에 본 연구에서는 민꽃게의 수입 성능적 그물 통발은 한계가 있다고 보고, 민꽃게의 습성을 고도로 이용함으로써 수입성능을 높일 수 있는 2종류의 어구를 고\ulcorner 하여 수조실험과 해상실험을 통해 금.고(1987, 1990)가 개발한 통발과 비교 실험을 행하였다. 실험에서 얻어진 결과를 요약하면 다음과 같다. 1) 그물 통발과 파이프형 통발에서 시간의 경과에 따른 민꽃게의 접촉율과 반응율은 금.고(1987.1990)가 행한 사구식 각주형 그물 통발의 실험 결과와 대체로 일치하였지만, 평판형 얽애그물에서는 접촉율이 잠깐 증가하였다가 바로 감소하였고, 반응율은 급히 증가하기 시작하여 최대치를 보인 후 일정해지는 경향을 나타내 차이가 있었다. 2) 민꽃게의 입농시작 시간은 평판형 얽애그물에서 민꽃게가 그물에 접촉하기만 하면 신체의 일부분이 곧바로 그물에 얽혀버렸기 때문에 포획에 걸리는 시간이 다른 통발 어구에 비해 가장 짧게 나타났고, 다음이 파이프형 통발이며 그물 통발에서 가장 늦게 나타났다. 3) 민꽃게의 통발내 분포율을 나타내는 접촉율 곡선과 반응율곡선과의 시폭은 평판형 얽애그물에서 가장 빨리 그리고 많이 벌어져 민꽃게의 체포자체에 있어서는 그 성능이 가장 우수하게 나타났으며, 파이프형 통발의 경우 직경의 차이(${\phi}$ 150, 250mm)에 따라서는 큰 차이를 보이지 않았지만, 그물 통발에 비해 성능이 높게 나타났다. 4) 파이프형 통발은 입농한 민꽃게에 대해 통발내에서 정제하는 은신행동을 수발하게 하여 민꽃게의 은신처로 작용한다는 것을 알 수 있었다. 5)그물 통발과 파이프형 통발 및 평판형 얽애그물에 대한 어획 실험에서 어구 하나당 평균 어획량은 파이프형 통발에서 가장 많았고, 다음이 그물통발이였으며, 평판형 얽애 그물에서 가장 적어 수조실험과는 차이를 보였다.

• Journal of applied mathematics & informatics
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• 제6권1호
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• pp.127-142
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• 1999

This paper develops a methematical model for growth and exploitation of a schooling fish species using a realistic catch-rate function and imposing a tax on the catch to control harvesting. Fishing effort is assumed to depend on the net revenue. The steady states of the system are determined and their local and global stabil-ity are discussed. Taking the tax as a control variable; the optimal harvest policy is formulated and solved as a control problem. The results are illustrated with the help of a numerical example.

• 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.

• 수산해양기술연구
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• 제49권1호
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• pp.18-28
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• 2013

It was compared the estimated parameters by the surplus production from three different models, i.e., three types (Schaefer, Gulland, and Schnute) of the traditional surplus production models, a stock production model incorporating covariates (ASPIC) model and a maximum entropy (ME) model. We also evaluated the performance of models in the estimation of their parameters. The maximum sustainable yield (MSY) of small yellow croaker (Pseudosciaena polyactis) in Korean waters ranged from 35,061 metric tons (mt) by Gulland model to 44,844mt by ME model, and fishing effort at MSY ($f_{MSY}$) ranged from 262,188hauls by Schnute model to 355,200hauls by ME model. The lowest root mean square error (RMSE) for small yellow croaker was obtained from the Gulland surplus production model, while the highest RMSE was from Schnute model. However, the highest coefficient of determination ($R^2$) was from the ME model, but the ASPIC model yielded the lowest coefficient. On the other hand, the MSY of Kapenta (Limnothrissa miodon) ranged from 16,880 mt by ASPIC model to 25,373mt by ME model, and $f_{MSY}$, from 94,580hauls by ASPIC model to 225,490hauls by Schnute model. In this case, both the lowest root mean square error (RMSE) and the highest coefficient of determination ($R^2$) were obtained from the ME model, which showed relatively better fits of data to the model, indicating that the ME model is statistically more stable and robust than other models. Moreover, the ME model could provide additional ecologically useful parameters such as, biomass at MSY ($B_{MSY}$), carrying capacity of the population (K), catchability coefficient (q) and the intrinsic rate of population growth (r).

• 수산경영론집
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• 제41권1호
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• pp.129-156
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• 2010

Well-deviced buyback programs may be detrimental to achieve sustainable fisheries. However, it is not difficult to find undesirable examples that the result of buyback program have no impact on fish stocks or the sustainability of the fishery. This paper discusses the problems and policy directions for successful restructuring of Korean marine fisheries through comparative analysis of selected cases from five main countries including Japan, Norway, Italy, Taiwan and Australia. From the analysis, this study demonstrated that Korean buyback program just pursue the reduction of boat number but passed over alleviation of the real ability in fishing industry. Although there were clear decrease of fishing effort in a certain parts of fisheries and some evidences of advancement in efficiency, it seemed hard to continue these effects because the Korean policy lacks consistency and coherence of systematic restructuring. To summary, four things are recommended for successful application of Korean buyback program; first is to establish the obvious goal of the program, second is to introduce downsizing in both fleet capacity and engine power, third is to conduct other management tools simultaneously to help resource restoration, and last, but not the least is to induce voluntary participation of fishermen providing opportunity to pursue their mutual interest.

• 수산해양기술연구
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• 제42권4호
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• pp.240-258
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• 2006

The potential of ecosystem-based fisheries management is recently recognized to be very important to improve the sustainability of fisheries resources. Under the depressed condition of many fisheries resources, this recognition has been expanded and more effort has been taken to improve this approach. Taking ecosystem concept includes the use of other tools of management in addition to fisheries regulation, such as stock and productivity enhancement, provision of physical structure, or marine protected areas. In the ecosystem-based fisheries management approach, it would require to holistically consider ecological interactions of target species with predators, competitors, and prey species, the effects of climate on fisheries ecology, the complex interactions between fishes and their habitat, and the effects of fishing on fish stocks and their ecosystem. Fisheries management based upon the understanding of these factors can prevent significant and potentially irreversible changes in marine ecosystems caused by fishing. A useful approach for analyzing tropho-dynamic interactions and mass-balance in marine ecosystems is introduced to demonstrate the complexity and usefulness of the ecosystem approach, which was applied to a small ecosystem in Korea. Korea should seriously consider to take the ecosystem-based approach to fisheries management, since most major fish stocks are currently depleted due to many reasons such as overfishing, land reclamation and coastal pollution.