• 한국환경과학회지
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• 제17권4호
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• pp.461-468
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• 2008

Competitive power of pelagic fishery in Korea has been weakened by the domestic and international problems such as wage increase and exclusive economic zone. To make it worse, fishing fleet spends more than 80% of fishing time on searching fishing grounds. Real-time information on oceanographic data, temperature in particular, are likely to contribute to raise efficiency of fishing. However, available data obtained by satellite remote sensing, fixed buoy and drifting buoy, limited to sea surface or fixed positions. ARGO (Array for Real-time Geostrophic Oceanography), an international program, has delivered vertical profiles of temperature and salinity in the upper 2000m of the world ocean every 10 days using freely moving floats. We have developed real-time oceanographic information system for pelagic fishery based on the Argo data which has the contents of vertical profile, horizontal distribution and vertical section of temperature around fishing grounds and searched data can be download unrestrictedly. Comparison of skipjack catch with sea surface temperature and depth of $20^{\circ}C$ derived from Argo data in the West Equatorial Pacific revealed that Argo data are able to help fishing fleet to find fishing grounds and to increase catch.

• 한국물환경학회지
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• 제23권5호
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• pp.676-682
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• 2007

The bacterial number, extracellular enzyme activities and structure of bacterial community which are major constituent of aquatic ecosystem within the artificial vegetation island (AVI) were compared to those of the nearby pelagic lake waters in order to evaluate the possibility of the AVI as a eco-technological measure for water quality improvement and restoration of littoral zone in man-made reservoirs. There was not a significant difference in the total number of bacteria, but the number of active (viable) bacteria within the AVI was about 0.7 to 4.1 times higher than nearby pelagic lake water. The ratio of the number of active bacteria versus the total number of bacteria was also higher in the AVI than nearby pelagic lake water. The activities of ${\beta}$-glucosidase and phosphatase were 1.0 to 13.1 and 0.8 to 7.3 times higher respectively in the AVI than nearby pelagic lake water, showing that microorganisms were more active within the AVI. The bacterial communities of the two waters, examined by FISH method, did not indicate a clear difference in the springtime when the growth of macrophytes was immature, but during summer and fall it showed a clear difference indicating the formation of distinct bacterial community within the AVI compared to nearby lake water. From the results of this study, we conclude that AVI can contribute to make up the littoral ecosystem which show rapid cycling of matters through active detritus food chain in the dam reservoirs which have unstable aquatic ecosystem due to short hydraulic residence time and to strengthen the self-purification capacity of the lake.

• Journal of Ecology and Environment
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• 제30권1호
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• pp.23-38
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• 2007

Based on a time series of ocean climate indices and catch records for seven pelagic fish species in the Tsushima Warm Current (TWC) and Kuroshio-Oyashio Current (KOC) regions from 1910 to 2004, we detected regional synchrony in the long-term fluctuations of the fish populations and identified alternation patterns of dominant species related to climate shifts. The annual catches of Pacific herring, Japanese sardines, Japanese anchovies, jack mackerel, chub mackerel, Pacific saury and common squid in the TWC region fluctuated in phase with those in the KOC region, which suggests that they were controlled by the same basin-wide climate forcing. After the collapse of the herring fishery, the alternation sequence was: sardines (1930s), Pacific saury, jack mackerel, common squid and anchovies ($1950s{\sim}1960s$), herring ($late\;1960s{\sim}early\;1970s$), chub mackerel (1970s) and then sardines (1980s). As sardine biomass decreased in the late stages of the cool regime, catch of the other four species increased immediately during the warm period of the 1990s. Regional differences in the amplitude of long-term catch fluctuations for the seven pelagic fishes could be explained by regional differences in availability, fishing techniques and activity.

• 환경생물
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• 제30권1호
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• pp.64-70
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• 2012

This study compares the abundance and community structure of zooplankton organisms from the littoral and pelagic regions, and considers particularly trophic levels vs. zooplankton abundances. Zooplankton samples, collected every 3 months over a year from 2010 to 2011 at 29 temperate lakes and reservoirs, which belong to two different river basins (Youngsan and Seomjin River). The spatial pattern of rotifers was similar to that of total zooplankton abundance. This reflected the fact that rotifers strongly dominated the zooplankton community. There were considerable spatial variations in total zooplankton abundance (ANOVA, p<0.01), while there were no significant differences both in littoral and pelagic regions in abundance of zooplankton (ANOVA, p=0.205). The mean abundance of zooplankton in eutrophic systems was much higher than that of mesotrophic systems, while significant difference in number of species and diversity index were not shown in both trophic systems.

• 대한조선학회지
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• 제8권2호
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• pp.53-64
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• 1971

• 한국해양학회지
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• 제22권4호
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• pp.236-245
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• 1987

천수만에서 금강 하구에 이르는 13개 정점에서 1985년 7월부터 1986년 6월에 걸쳐 부유성 난과 자치어를 채집하였는데, 이중 부유성 난은 19개 분류군으로, 자치어는 8 月 28 科에 속하는 45개 분류군으로 동정 되었다. 본 연구에서는 부유성난과 자치어의 동정을 위한 검색표 작성의 일환으로 부유성난에 대해서는 유구의 수, 난의 형태, 난막의 돌기, 난경, 유구경 등의 형질에 따라 19개 분류군의 검색표를 작성하였으며, 자치어에 대해서는 體形, 肛門의 위치 色素胞의 배열 등의 형태적인 형질에 따라 우선 科 수준의 檢索表를 작성하였다.

• 한국수산과학회지
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• 제44권4호
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• pp.378-382
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• 2011

The feeding ecology of bluefin searobin Chelidonichthys spinosus around Jeju Island was examined. Specimens were caught every autumn from 2004 to 2007. The primary prey items of C. spinosus included fish, shrimp, and crabs. Chelidonichthys spinosus preyed upon a wide range of sub-pelagic crustacean groups(e.g., Leptochela gracilis, Leptochela sydniensis). This species was also an opportunistic feeder, exploiting the available prey groups in each area(i.e., L. gracilis in the South Sea and East China Sea groups and L. gracilis and L. sydniensis in the Yellow Sea group). The main prey group of this species changed from demersal shrimp to pelagic shrimp with prey environmental changes. Observed ontogenetic shifts in diet were relatively clear despite substantial overlap between the 10 cm and 20 cm C. spinosus groups.

• 수산경영론집
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• 제26권1호
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• pp.29-40
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• 1995

Since the coastal countries, such as Unite States and other Latin America countries, proclaimed their 200 nautical mile Exclusive Economic Zone, these countries have attention to the need to develop effective coastal management and resource conservation But these countries often perceive themselves as being in competition with each other for profitable for the expansion of the vested EEZ. In such a situation, Exclusive Economic Zone expansion can appear as attractive policy tools in a coastal fishing firms in a noncooperative rivalries with pelagic countries, enable them to expand their fishing share and earn more profits. In reality, the coastal countries strategic Exclusive Economic Zone expansion change the initial condition of the game that both countries' fishing firms play. In this case, the coastal countries' fishing, such as South Korea, Japan and others, act as a followers. As result, the coastal countries' welfare is improved because of pelagic countries profit share shifts to the coastal countries profit share. In this paper, we find that coastal countries strategic EEZ expansion policy may not improve the coastal contries welfare if the shifting profits are dominated by the direct lobbying costs and related resource depletion.

• Animal Systematics, Evolution and Diversity
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• 제36권3호
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• pp.236-239
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• 2020

Pelagic tunicate, Thetys vagina Tilesius, 1802, is newly reported from Korean waters. The genus Thetys Tilesius, 1802 is also first recorded as Korean fauna. Thetys vagina is the only valid species in the genus Thetys. It is distinct from other genera by having at least 16 body muscles widely interrupted, no anterior proboscis, bent alimentary canal in the solitary oozooid, and five narrow body muscles, no ventral peduncle, an almost compact loop alimentary canal in the aggregate blastozooids. The specimens of T. vagina examined in this study were collected at the subtidal zone of Ulleung-do Island by scuba diving. In this paper, the detailed descriptions and photographs of both the solitary and aggregate living forms of T. vagina are provided.

• Animal Systematics, Evolution and Diversity
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• 제36권4호
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• pp.408-415
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• 2020

The suborder Hyperiidea is an abundant crustacean zooplankton in pelagic communities with copepods and euphausiaceans. Hyperiidean amphipods are known to be commensals or parasites of gelatinous organisms such as medusae, siphonophores, ctenophores, and salps. Korean hyperiid amphipods have not received taxonomical attention since the 1970s. During a survey of pelagic crustacean species, two species of hyperiid amphipods, Phronima atlantica Guérin-Méneville, 1836 belonging to the family Phronimidae and Oxycephalus clausi Bovallius, 1887 belonging to the family Oxycephalidae, were found on Dokdo, East Sea, Korea. These two species are new to Korean waters. In the present study, we provide descriptions and illustrations of these two hyperiid species.