• Title/Summary/Keyword: deep-sea fisheries

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Distribution of water Masses and Chemical Properties in the East Sea of korea in Spring 2005 (2005년 춘계 동해 중남부 해역의 수괴 분포 및 화학적 특성 연구)

  • Kim, Y.S.;Hwang, J.D.;Youn, S.H.;Yoon, S.C.;Hwang, U.G.;Shim, J.M.;Lee, Y.H.;Jin, H.G.
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.10 no.4
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    • pp.235-243
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    • 2007
  • In order to understand the water mass properties in the southern location of the East Sea in the Korean coasts, the vertical distributions (down to 2,000 m deep) of water temperature, salinity, and dissolved inorganic nutrients were determined in April of 2005. The water mass of the surveyed location showed distinct vertical layers; highly saline surface, surface mixing layer, and thermocline of low temperature and salinity. The water layer below 300 m was characterized by water temperature lower than $1^{\circ}C$ and salinity 34.06, showing a representative water mass of the East Sea. The inorganic nutrients rapidly increased from 200m in the northern and southern parts around Ulleung Basin. A marked environmental difference was found between two layers separated by thermocline. The upper layer of the thermocline was oligotrophic and the vertical distribution of nutrient was very stable. In the water layer between 100 and 200m the nutrients slightly increased but remained still stable. From southern coasts to northeastern Ulleung, the water mass properties were site specific; the thickness of the surface mixed layer and nutricline showed a trend diminishing toward the northern locations probably due to diminished influence of Tsushima water. Redfield ratio (N:P=16:1) based on the ratio of chemical composition in organism revealed that nitrogen value continuously decreased to less than 16 with the water depth down to loom from the thermocline. The value in the water layer deeper than 100 to 200 m, thereafter, showed an increasing trend (over 16). This result was further supported by the finding of lower chlrophyll a content in the layer.

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A Study on Sea Surface Temperature Changes in South Sea (Tongyeong coast), South Korea, Following the Passage of Typhoon KHANUN in 2023 (2023년 태풍 카눈 통과에 따른 한국 남해 통영해역 수온 변동 연구)

  • Jae-Dong Hwang;Ji-Suk Ahn;Ju-Yeon Kim;Hui-Tae Joo;Byung-Hwa Min;Ki-Ho Nam;Si-Woo Lee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.1
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    • pp.13-19
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    • 2024
  • An analysis of the coastal water temperature in the Tongyeong waters, the eastern sea of the South Sea of Korea, revealed that the water temperature rose sharply before the typhoon made landfall. The water temperature rise occurred throughout the entire water column. An analysis of the sea surface temperature data observed by NOAA(National Oceanic and Atmospheric Administration) satellites, indicated that sea water with a temperature of 30℃ existed in the eastern waters of the eastern South Sea of Korea before the typhoon landed. The southeastern sea of Korea is an area where ocean currents prevail from west to east owing to the Tsushima Warm Current. However, an analysis of the satellite data showed that seawater at 30℃ moved from east to west, indicating that it was affected by the Ekman transport caused by the typhoon before landing. In addition, because the eastern waters of the South Sea are not as deep as those of the East Sea, the water temperature of the entire water layer may remain constant owing to vertical mixing caused by the wind. Because the rise in water temperature in each water layer occurred on the same day, the rise in the bottom water temperature can be considered as owing to vertical mixing. Indeed, the southeastern sea of Korea is a sea area where the water temperature can rise rapidly depending on the direction of approach of the typhoon and the location of high temperature formation.

Fisheries Resources -A Brief Introduction of the Republic of Senegal

  • Mbengue, Modou
    • Journal of Marine Bioscience and Biotechnology
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    • v.3 no.1
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    • pp.38-41
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    • 2008
  • Fish is a major source of protein for the Senegalese population. Fishing plays a dominant role in the Government's policy towards generating employment. It currently generates about 100,000 direct jobs (fishermen) for nationals, of which more than 90% are in small-scale fishing. The fishing industry also contributes to Government revenue through different agreements. In addition to associated dues, fishing agreements imply a series of economic, trade and technical counterparts. Under the latest fishing agreement concluded by Senegal and the European Union (1997-2001), direct financial compensation amounts to about CFAF 32 billion. Despite its economic and social importance, the sector has to face serious disequilibria both in resource exploitation and market supply: the coastal demersal (deep lying fish) stocks with high market value (mostly exported) are fully and even over-exploited, with a serious risk of local market supply shortages looming ahead as the fishing effort shifts from locally consumed species to export-oriented ones.

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A review on fish bio-logging for biotelemetry applications

  • Jikang Park;Sung-Yong Oh
    • Fisheries and Aquatic Sciences
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    • v.26 no.12
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    • pp.698-707
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    • 2023
  • Fish are an essential resource in human society, and while ecological research on them is challenging, it is absolutely necessary. Recent technologies enabled researchers to monitor underwater fish behavior. Acoustic signals, satellite-mediated location estimation, and light-based geolocation are powerful tools for tracking fish movements from freshwater to deep-sea habitats. These tools allow us to track various fish species and elucidate their ecology. Furthermore, based on these technologies, we can develop fisheries management plans and enhance aquaculture productivity. In this review, we also discuss challenges in improving current technologies and provide future recommendations for fish bio-logging studies.

Foreign Entry Strategies for Korean Fishery Firms (한국수산업의 해외진출전략에 관한 연구)

  • 김회천
    • The Journal of Fisheries Business Administration
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    • v.15 no.1
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    • pp.131-153
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    • 1984
  • Fishery resources are still abundant compared with other resources and the possibility of exploitation is probably great. The Korean fishery industry has grown remarkably since 1957, and Korea is ranked as one of the major fishery countries. Its of fishery products reached the 9th in the world and the value of exports was 5th in 1982. But recently a growth rate has slowed down, due to the enlargement of territorial seas by the declaration of the 200 mile, Exclusive Economic Zone, the tendency to develop fishery resources strate-gically in international bargaining, the change in function of the international organizations, the expansion of regulated waters, the illegal arrest of our fishing boats, the rapid rise in oil prices, and the fall in fish prices, the development of fishery resources as a symbol of nationalism, the fishing boats decreptitude, the rise of crew wages, regulations on fishing methods, fish species, fishing season, size of fish, and mesh size, fishing quotas and the demand of excessive fishing royalties. Besides the the obligation of coastal countries, employing crews of their host countries is also an example of the change in the international environment which causes the aggravation of foreign profit of fishing firms. To ameliorate the situation, our Korean fishery firms must prepare efficient plans and study systematically to internationalize themselves because such existing methods as conventional fishing entry and licence fishing entry are likely to be unable to cope with international environmental change. Thus, after the systematic analysis of the problem, some new combined alternatives might be proposed. These are some of the new schemes to support this plan showing the orientation of our national policy: 1. Most of the coastal states, to cope with rapid international environmental change and to survive in the new era of ocean order, have rationalized their higher governmental structure concerning the fishery industries. And the coastal countries which are the objectives of our expecting entry, demand excessive economic and technical aid, limit the number of fishing boats’entry and the use of our foreign fishing bases, and regulate the membership of the international fishery commissions. Especially, most of the coastal or island countries are recently independent states, which are poorer in national budget, depend largely on fishing royalties and licence entry fees as their main resources of national finance. 2. Alternatives to our entry to deep sea fishing, as internationalization strategies, are by direct foreign investment method. About 30 firms have already invested approximately US $ 8 million in 9 coastal countries. Areas of investment comprise the southern part of the Atlantic Ocean, the Moroccan sea and five other sea areas. Trawling, tuna purse seining and five other fields are covered by the investment. Joint-venture is the most prominent method of this direct investment. If we consider the number of entry firms, the host countries, the number of seas available and the size of investment, this method of cooperation is perhaps insufficient so far. Our fishery firms suffer from a weakness in international competitive ability, an insufficiency of information, of short funds, incompetency in the market, the unfriendliness of host coastal countries, the incapability of partners in joint-ventures and the political instability of the host countries. To enlarge our foreign fishing grounds, we are to actively adopt the direct investment entry method and to diversity our collaboraboration with partner countries. Consequently, besides proper fishing, we might utilize forward integration strategies, including the processing fied. a. The enterprise emigration method is likely to be successful in Argentina. It includes the development of Argentinian fishing grounds which are still not exploited in spite of abundant resources. Besides, Arentina could also be developed as a base for the exploitation of the krill resources and for further entries into collaboration with other Latin American countries. b. The co-business contract fishing method works in American territorial seas where American fishermen sell their fishery products to our factory ships at sea. This method contributes greatly to obtaining more fishing quotas and in innovation bottom fishing operation. Therefore we may apply this method to other countres to diffuse our foreign fishing entry. c. The new fishing ground development method was begun in 1957 by tuna long-line experimental fishing in the Indian Ocean. It has five fields, trawling, skipjack pole fishing and shrimp trawling, and so on. Recently, Korean fisheries were successful in the development of the Antarctic Ocean krill and tuna purse seining. 3. The acceleration of the internationalization of deep sea fishing; a. Intense information exchange activities and commission participation are likely to be continues as our contributions to the international fishery organizations. We should try to enter international fishery commissions in which we are not so far participating. And we have to reform adequately to meet the changes of the function of the international commissions. With our partner countries, we ought to conclude bilateral fishery agreements, thus enlarging our collaboration. b. Our government should offer economic and technical aids to host countries to facilitate our firms’fishery entry and activities. c. To accelerate technical innovation, our fishery firms must invest greater amount in technical innovation, at the same time be more discriminatory in importing exogeneous fishery technologies. As for fishing methods; expanded use of multi-purpose fishing boats and introduction of automation should be encuraged to prevent seasonal fluctuations in fishery outputs. d. The government should increases financial and tax aid to Korean firms in order to elevate already weak financial structure of Korean fishery firms. e. Finally, the government ought to revise foreign exchange regulations being applied to deep sea fishery firms. Furthermore, dutes levied on foreign purchaed equipments and supplies used by our deep sea fishing boats thould be reduced or exempted. when the fish caught by Korean partner of joint-venture firms is sold at the home port, pusan, import duty should be exempted.

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A Study on Cold Water Damage to Marine Culturing Farms at Guryongpo in the Southwestern Part of the East Sea (경북 구룡포 해역에서의 냉수 발생과 어장 피해)

  • Lee, Yong-Hwa;Shim, JeongHee;Choi, Yang-ho;Kim, Sang-Woo;Shim, Jeong-Min
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.6
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    • pp.731-737
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    • 2016
  • To understand the characteristics and strength of the cold water that has caused damage to marine-culturing farms around Guryongpo, in the southwestern part of Korea, surface and water column temperatures were collected from temperature loggers deployed at a sea squirt farm during August-November 2007 and from a Real-time Information System for Aquaculture environment operated by NIFS (National Institute of Fisheries Science) during July-August 2015 and 2016. During the study period, surface temperature at Guryongpo decreased sharply when south/southwestern winds prevailed (the 18-26th of August and 20-22nd of September 2007 and the 13-15th of July 2015) as a result of upwelling. However, the deep-water (20-30m) temperature increased during periods of strong north/northeasterly winds (the 5-7th and 16-18th of September 2007) as a result of downwelling. Among the cold water events that occurred at Guryongpo, the mass death of cultured fish followed strong cold water events (surface temperatures below $10^{\circ}C$) that were caused by more than two days of successive south/southeastern winds with maximum speeds higher than 5 m/s. A Cold Water Index (CWI) was defined and calculated using maximum wind speed and direction as measured daily at Pohang Meteorological Observatory. When the average CWI over two days ($CWI_{2d}$) was higher than 100, mass fish mortality occurred. The four-day average CWI ($CWI_{4d}$) showed a high negative correlation with surface temperature from July-August in the Guryongpo area ($R^2=0.5$), suggesting that CWI is a good index for predicting strong cold water events and massive mortality. In October 2007, the sea temperature at a depth of 30 m showed a high fluctuation that ranged from $7-23^{\circ}C$, with frequency and spectrum coinciding with tidal levels at Ulsan, affected by the North Korean Cold Current. If temperature variations at the depth of fish cages also regularly fluctuate within this range, damage may be caused to the Guryongpo fish industry. More studies are needed to focus on this phenomenon.

Distribution of Common Squid Todarodes pacificus Larvae in the Southwestern Part of the East Sea in Summer and Autumn, 2015 (2015년 하계 및 추계 동해 남서해역에서 출현하는 살오징어 (Todarodes pacificus) 유생의 분포 양상)

  • KIM, Yoon-Ha;SHIN, Dong-Hoon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.2
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    • pp.220-228
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    • 2019
  • To determine the horizontal and temporal distribution of common squid larvae, Todarodes pacificus (hereafter T. pacificus), we conducted surveys using an IKMT net (mesh size: $500{\mu}m$) with a Fisheries Research Vessel (FRV, TAMGU 21) in the southwestern part of the East Sea in summer (August and September) and autumn (November) 2015. A total of 228 larvae, ranging in mantle length (ML) from 1.4 mm to 21.9 mm, were collected at 35 stations over the research period. The monthly average mantle length of T. pacificus larvae did not differ significantly in August, September and November. (p > 0.05). Catch densities at positive stations ranged between 0.1 and $7.9inds./1,000m^3$ over the research period. Incidence rates of T. pacificus larvae were similar over three months, in the study area (62.9 % - 68.6 %). The 4 - 5 mm mantle length range had the highest frequency in size-frequency distributions for T. pacificus larvae. The larval survival temperature ($15-24^{\circ}C$) at positive stations for catch densities was located below a 20 m depth in August whereas it was located at the surface of the water in September and November. The survival temperature for larvae existed from the bottom to the surface of the water where larvae were sampled larvae in shallow sea areas. However, the larval survival temperature occurred in a shallower location than the upper layer of the thermocline in deep sea areas at a depth below 100 m.

A Study on Legislation for the Improvement of the Marine Environment and Safety Act for Deep Sea Drilling (심해 시추와 관련된 국내 해양 환경 및 안전 관련법 개선에 대한 입법론적 연구)

  • Hong, Sung-Hwa;Lee, Chang-Hee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.1
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    • pp.73-82
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    • 2017
  • This study is focused on concepts and types of drilling investigating the scope of activity and problems the application of marine environment and safety acts related to deep-sea drilling for the development of the continental shelf in Korea. For the systemic development of subsea mineral resources, this study suggest a legislative proposal for the establishment of a separate law based on the UK Offshore Installation (Safety Case) regulation and improvement of the marine environment management act, maritime safety act and oil & mining safety regulation. Specially, this study emphasized on the necessity of establishing education, training and evaluation system according to the international certification training for the domestic work force based on accident cases related to overseas offshore plants.

Community Analysis and Pathogen Monitoring in Wild Cyprinid Fish and Crustaceans in the Geum River Estuary (금강 하구 자연수계 생물체의 군집 분석 및 질병 원인체 검사)

  • Kim, So Yeon;Hur, Jun Wook;Cha, Seung Joo;Park, Myoung Ae;Choi, Hye-Sung;Kwon, Joon Yeong;Kwon, Se Ryun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.3
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    • pp.248-253
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    • 2018
  • Freshwater farms are primarily located adjacent to rivers and lakes, facilitating the introduction and spread of pathogens into natural systems. Therefore, it is necessary to continuously monitor natural aquatic organisms, the breeding environment, and infection rates by pathogenic organisms. Fish and crustaceans were sampled 4 times in the Geum River estuary in 2016. The samples were analyzed for the presence of pathogens for reportable communicable diseases, including KHVD (koi herpesvirus disease), SVC (spring viraemia of carp), EUS (epizootic ulcerative syndrome) and WSD (white spot disease); parasite abundance was also examined. The dominant fish species were deep body bitterling Acanthorhodes macropterus (21.4%), followed by skygager Erythroculter erythropterus (12.7%). For crustaceans, Palaemon paucidens and Chinese mitten crab Eriocheir sinensis were dominant. Sixty fish and 36 crustacean species were examined for reportable communicable diseases. When using a specific primer set for each disease, PCR analysis did not detect any reportable communicable diseases in the samples. Some instances of Dactylogyrus, copepods, nematodes and metacercaria were detected. However, the PCR results indicated that the metacercaria were not Clonorchis sinensis.

Age and Growth of the Yellow Goosefish, Lophius litulon (한국근해 황아귀, Lophius litulon의 연령과 성장)

  • CHA Byung-Yul;PARK Yeong-Chull;HUH Sung-Hoi
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.4
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    • pp.529-534
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    • 1998
  • Age and growth of the yellow goosefish, Lophius litulon, were studied using samples collected from the southwestern waters of Korea. Vertebrae of the fish had relatively clear annuli on their surface. The opaque zone of vertebrae was formed once a year between March and April. The oldest fish observed in this study was 8 years old for females and 5 years old for males. The relationship between the radius (R) of vertebral centrum and total length (L) was as follows: L=12.7+4.8R for females and L=9.8+5.6R for males. The relationship between total length and body weight (W) was as follows : $W=0.0089L^{3.0311}$ for females and $W=0.0329L^{2.7752}$ for males. Growth in length of the fish was expressed by the von Bertalanffy's equation as $L_t=127.60(1-e^{-0.1228(t+0.3851)})$ for females and $L_t=82.23(1-e^{-0.1832(t+0.6431)})$ for males.

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