• Journal of Forest and Environmental Science
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• v.34 no.1
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• pp.66-70
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• 2018

Preliminary investigation and analysis of the effectiveness of controlling the number of ecosystem disturbance fishes residing in Togyo reservoir using the native carnivorous fish species were performed. The data were collected from August 2011 to November 2016. The release of native carnivorous fish species was carried out from the end of May, 2012 to the end of July, 2016, considering fishing ban period of Siniperca scherzeri. The comparative abundance of Lepomis macrochirus was found to be 12.8% in the first year and increased a little bit after releasing the native carnivorous fish. However, it decreased to 3.9% in the last year showing a value of less than 5%. On the other hand, the Micropterus salmoides populations tended to increase after the release of native carnivorous fish species. This seems to be the result of the segregation of habitat by interspecific competition with S. scherzeri. The M. salmoides moved from inside of the lake to edges, and to influent tributaries. Stable isotope analysis showed that Channa argus had the highest levels of nutrition, S. scherzeri and M. salmoides were in competition, and L. macrochirus was used as a feed source for released species. Changes of the fish community in the Togyo reservoir was represented by the rank abundance curves based on the results of the fish fauna. As a result, the fish group in incoming tributaries are somewhat disturbed after the release of the native carnivorous species. Similarly, the fish group in the reservoir were disturbed as well but it's gradually stabilizing afterwards. Therefore, the control of the ecosystem disturbance species using the native carnivorous fish of Korea is effective and helps to stabilize the fish community in the lake.

• 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.