• 수산경영론집
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• 제52권3호
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• pp.27-38
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• 2021

This study is aimed to figure out the productivity and variability of cage-aquaculture changes. According to the analysis, the productivity of major fish species has been increasing, except mullet. Although the regional productivity has decreased in the last two years, it has been on the rise considering as a whole. Gyeongsangnam-do showed the highest level of productivity by region. Productivity by species was also higher than other regions in the cases of rock fish, mullet and sea bream followed by productivity of Chungcheongnam-do. The production of marine cage-culture in Jeollanam-do is the second largest in Korea in value/weight while its productivity is lower than that of Chungcheongnam-do. When it comes to comparison by region, Gyeongsangnam-do shows the lowest productivity variation. And Jeollanam-do shows the second-lowest variation in productivity that is only about half of that of Chungcheongnam-do province. Thus, it is found that Jeollanam-do region has an advantage in management stability while its productivity is low. On the other hand, productivity by species was also analyzed. Gyeongsangnam-do has the highest productivity by species for rock fish, mullet and sea bream whereas rock bream productivity is the highest in Jeollanam-do. Therefore, it probably needs to reflect these results when choosing regional-focused incubation fish species.

• 수산경영론집
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• 제25권2호
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• pp.115-145
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• 1994

The objetives of this study are to find the economic feasibility of the polyculture and to give the economic information of the polyculture for aquaculture fishermen. The polyculture is defined as the rearing of several species together to make more efficient use of the growing space and the total ground environment. The economic feasibility analysis in the polyculture involves the profitability, the productivity, and the risk reduction effect. The results of the economic feasibility analysis in the polyculture are as follows; First, in the profitability analysis, the solid utilization of ground in the polyculture is more profitable than the monoculture. The profitability owing to the plane utilization of the ground in the polyculture is positioned between those of the monoculture of each speices. Second, in the productivity analysis, oyster and sea squirt are diminishing returns to scale. Third, the variation on the average rate of return in the polyculture products is smaller than that of the monoculture. Finally, the result of comparison between the polyculture and the monoculture shows that the polyculture in coastal area is more profitable and more efficient than the monoculture. Most of cultivating species are selective in their diet Thus, stocking different kinds of cultivating species will efficiently utilize space and food It seems that polyculture is more appropriate for those species that live in different ecological niches. We think that the production per unit of ground can be increased, and the fixed cost per unit of output be reduced, so the polyculture is more profitable than the monoculture. Based on the above results, we concludes that the polyculture is economically feasible when profitability and productivity are increased and simultaneously the variation of average rate of return in the polyculture is smaller than that of the monoculture.

• 해양환경안전학회지
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• 제19권6호
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• pp.570-581
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• 2013

어장관리해역으로 지정된 옹진군의 수질 및 퇴적물 환경 특성을 파악하기 위하여 2011년에 4개 도서(장봉도, 자월도, 영흥도, 백령도)를 대상으로 조사를 실시하였다. 수온은 $9.49{\sim}24.14^{\circ}C$로 계절변동 특성을 잘 나타내었고, 염분(23.19~31.49)과 용존산소(5.48~9.36 mg/L)는 수온과 역상관성을 보였으며, 화학적산소요구량(COD)은 평균 1.57 mg/L로 전체적으로 양호한 수준이었다. DIN과 DIP는 각각 0.111~0.666 mg/L, 0.002~0.043 mg/L의 범위로 전 정점에서 낮은 분포를 보였고, 엽록소 a의 농도는 $0.02{\sim}8.07{\mu}g/L$ 범위로 서해의 다른 해역보다 낮았다. 퇴적물의 입도 분포는 모래와 실트가 각각 56.7 %, 34.6 %로 우세하였고, 분급은 불량하였다. 퇴적물의 화학적산소요구량과 강열감량은 각각 $1.00{\sim}11.03mg/g{\cdot}dry$, 0.72~5.29 %의 범위로 시 공간적으로 유사한 경향을 보였다. 총유기탄소와 총질소의 C/N ratio는 8.17~17.97 범위로 하계에 육상기원과 해양기원에 의한 영향이 혼재하는 것으로 나타났다. 표층퇴적물의 미량금속 오염도 평가를 위해 농집지수($I_{geo}$)를 계산한 결과, Cr과 As를 제외한 나머지 금속원소에 의한 오염은 없는 것으로 판단된다. 이러한 연구 결과는 본 연구지역이 전체적으로 양호한 수질을 보이며, 유기물과 금속원소에 의한 표층퇴적물의 오염이 없다는 것을 보여준다.