• Ocean and Polar Research
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• 제29권2호
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• pp.123-134
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• 2007

Distribution patterns of sandy bottom macrobenthic communities were studied around the Hupo coastal area. The seasonal surveys were conducted at 15 chosen sites within a depth range of 10 to 50 m along 10 km of the coastline using a Smith-McIntyre grab $(0.05\;m^2)$ in 2005. Overall depth distribution following the direction of the offshore become deeper parallel to the coastline. A total of 319 macrobenthic species were sampled with a mean density of $1,972\;ind./m^2$, and mean biomass was 82.5 wet-weight $g/m^2$. The major individual-dominant species were three polychaetes Spiophanes bombyx ($436\;ind./m^2$), Scoletoma longifolia ($250\;ind./m^2$) and Magelona japonica ($170\;ind./m^2$), and bivalve Adontorhina subquadrata ($73\;ind./m^2$). Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray-Curtis similarity identified 2 major station groups which corresponded to macrobenthic faunal assemblages and their characteristic species. In addition, environmental conditions were significantly different between station groups. Group I contained mostly 20 and 50 m deep sites and was associated with sandy mud. Group I was characterized by high abundance of S. bombyx, S. longifolia, A. subquadrata. It was divided into two sub-groups (I-I and I-II) in relation to depth. Sub-group I-I was associated with deeper sites than sub-group I-II. Group II included mostly inshore area shallower than 15 m and was associated with coarse and medium sand. Group II was characterized by Lumbrinerides hayashii and Urothoe grimaldii japonica.

• Fisheries and Aquatic Sciences
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• 제17권3호
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• pp.361-367
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• 2014

Cuttlefish Sepia esculenta are commercially important in Korea. Assessments of their biomass currently depend on fishery-landings data, which may be biased. Towards fishery-independent acoustic surveys of cuttlefish, target strength (TS) measurements at 70 and 120 kHz were made of 23 live cuttlefish, in early May 2010. The fish were caught by traps in the inshore waters around Geojedo, Korea. The TS were measured using split-beam echosounders (Simrad ES60 and EY500, respectively). The cuttlefish mantle lengths (L) ranged from 15.6 to 23.5 cm (mean L=17.8 cm) and their masses (W) ranged from 335 to 1020 g (mean W=556.1 g). Their mean TS values at 70 and 120 kHz were -33.01 dB (std=1.39 dB) and -31.76 dB (std=2.15 dB), respectively. The mean TS at 70 kHz was 0.17 dB higher than the TS-length relationship resulting from a least-squares fit to the data ($TS=24.67{\log}_{10}L(cm)-64.03$, $r^2$ = 0.52, N=23). The mean TS at 120 kHz was 0.45 dB higher than the fitted TS-length relationship ($TS=40.59{\log}_{10}L(cm)-82.96$, $r^2$ = 0.58, N=23). The differences between the mean TS values and an equation regressed from all of the TS measurements at both frequencies ($TS=24.92{\log}_{10}L(cm)-4.92{\log}_{10}{\lambda}(m)-22.82$, $r^2$ = 0.86, N=46) was 0.22 dB at 70 kHz and 0.31 dB at 120 kHz, respectively.

• 환경생물
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• 제18권4호
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• pp.447-456
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• 2000

마산-진해만에서 1990년 1월부터 1997년 8월까지 Prorocentrum 개체군 (P. dentatum Stein, P. micans Ehrenberg, P. minimum (Pavillard) Schiller, P. triestinum Schiller) 변동을 monitoring하였다. Prorocentrum 개체군은 대부분 6-8월 해수 성층화가 일어나는 시기에 bloom을 일으켰고 수온은 24-28$^{\circ}C$, 염분도는 24-34$\textperthousand$ 범위였다. 마산-진해만에서 Prorocentrum 개체군은 외만에서 내만으로 갈수록 발생빈도와 발생량이 증가하였고, 수직적으로는 2.5m상층부에 집중되었다. 또한 마산-진해만에서 Prorocentrum개체군은 과거 80년대와 90년대 초반과 비교하여 출현 종수는 감소하였으나 세포밀도는 점차적인 고밀도의 양상을 띠었다. 그리고 Prorocentrum 개체군은 과거와 비교하여 저수온기인 겨울철에도 출현빈도가 빈번해짐을 관찰하였다. Prorocentrum속 조류 중에서 P. minimum의 bloom규모와 그 지속 기간이 가장 길었다.

• Ocean Science Journal
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• 제42권2호
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• pp.117-127
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• 2007

The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at 10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in the marine ranching are a from September 2004 to November 2005. Water temperature varied from 12.1 to $28.9^{\circ}C$ (average $18.8^{\circ}C$), and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was $0.02-2.05\;{\mu}g\;L^{-1}$ (average $0.70\;{\mu}g\;L^{-1}$), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to 10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae, 13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was $2.21-48.69\times10^4\;cells\;L^{-1}$ (average $9.23\times10^4\;cells\;L^{-1}$), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking in November. The spring bloom was represented by four Chaetoceros species and Skeletonema costatum; each contributed 10-20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates, of which dinoflagellates were predominant. Gymnodinium conicum, Prorocentrum micans, and P. triestinum each contributed over 10% of the total phytoplankton abundance.

• 수산해양기술연구
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• 제36권4호
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• pp.322-328
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• 2000

남해안 연근해에서 조업하는 정치망 어선에 양망작업시 보조기계로 사용되는 캡스턴의 드럼에서 용접부 온도분포 및 구배를 해석한 결과의 주요 사항은 다음과 같다. 1. 용융부 근처는 냉각개시 1초 이내에 950$^{\circ}C$/sec, 10초 이내는 40$^{\circ}C$/see 정도의 급격한 냉각속도가 형성되었다. 2. 열영향부(HAZ)는 용접 후 1초가 경과할 때 370$^{\circ}C$/sec의 가열속도로 온도가 증가한 후, 이 후 25$^{\circ}C$/sec 냉각속도로 온도가 감소한다. 용접종료 10초 후 모재 내부에는 1.64$^{\circ}C$/mm, 40초가 지났을 때는 0.26$^{\circ}C$/mm 정도의 온도구배가 형성되었다. 3. 용접부 근처는 길이 방향을 따라 격심한 온도편차를 보이고 있으나 두께방향으로는 거의 나타나지 않는다. 이 결과는 향후 캡스턴 드럼의 용접부 최적설계시, 탄소성 열응력 및 열변형 거동을 해석하는 연구의 기초자료로 활용될 수 있을 것이다.

• 한국해양학회지
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• 제17권2호
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• pp.95-101
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• 1982

春季 한국 서해역에서의 동물플랑크톤 군집의 種組成 및 量的分布를 把握하 기 위하여 1981년 4월에 정량채집한 시료를 分析하였다. 수온 및 염분의 범위는 각 각 4.45$^{\circ}C$-9.8$0^{\circ}C$와 32.02 -32.88 였다. 총 33개 분류군이 分類 동정되었으며, 정 점간 種組成상의 차이는 두드러진 바 없었다. 각류 가장 우점하는 群으로서 우점 종은 Oithona similis, Acartia clausi, Centropages mcmurrichi 등이었다. 尾忠類, 毛顎類, 端脚類, Euphausiid類 등은 소량으로 분포하고 있었다. 동물플랑크톤의 現 在量(습중량)은 평균107mmmg/㎥였으며, 대상지역내에서는 육지쪽 정점에서보다 낮은 값을 보였다. 평균개체수는 1915개체/㎥로서, 정점별 분포양상은 현존량의분포 양상과비슷하였다. 각정점별, 분류군별 개체수를 통한 상관계수를 구하고 이를 토 대로 Cluster analyses을 해본 결과는 이 지역에서 수온은 동물플랑크톤의 분포에 상당한 영향을 미치고 있을 것으로 사료되었다.

• Fisheries and Aquatic Sciences
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• 제19권2호
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• pp.8.1-8.11
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• 2016

To quantitatively estimate the influence of cuttlebone on the target strength (TS) of golden cuttlefish, the cuttlebone was carefully extracted from 19 live cuttlefish caught using traps in the inshore waters around Geojedo, Korea, in early May 2010 and the TS was measured using split-beam echosounders (Simrad ES60 and EY500). The TS-length relationships for the cuttlefish (before the extraction of cuttlebone, Fish Aquat Sci. 17:361-7, 2014) and the corresponding cuttlebone were compared. The cuttlebone length ($L_b$) ranged from 151 to 195 mm (mean $L_b$ = 168.3 mm) and the mass ($W_b$) ranged from 29.3 to 53.2 g (mean $W_b$ = 38.8 g). The mean TS values at 70 and 120 kHz were -33.60 dB (std = 1.12 dB) and -32.24 dB (std = 1.87 dB), respectively. The mean TS values of cuttlebone were 0.19 dB and 0.04 dB lower than those of cuttlefish at 70 and 120 kHz, respectively. For 70 and 120 kHz combined, the mean TS value of cuttlebone was -32.87 dB, 0.11 dB lower than that of cuttlefish (-32.76 dB). On the other hand, the mean TS value of cuttlebone predicted by the regression ($TS_b$ = 24.86 $log_{10}$ $L_b$ - 4.86 $log_{10}$ ${\lambda}$ - 22.58, $r^2$ = 0.85, N = 38, P < 0.01) was -33.10 dB, 0.04 dB lower than that of cuttlefish predicted by the regression ($TS_c$ = 24.62 $log_{10}$ $L_c$ - 4.62 $log_{10}$ ${\lambda}$ - 22.64, $r^2$ = 0.85, N = 38, P < 0.01). That is, the contribution of cuttlebone to the cuttlefish TS determined by the measured results was slightly greater than that by the predicted results. These results suggest that cuttlebone is responsible for the TS of cuttlefish, and the contribution is estimated to be at least 99 % of the total echo strength.

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.283-292
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• 1998

The community dynamics and distribution of dinoflagellates and their cysts were monitored monthly from June 1996 to May 1997 at six stations in Masan-Chinhae Bay, one of the famous bays for red-tide occurrence in Korea. The dinoflagellate standing crops ranged from the minimum of 306 cells $ml^{-1}$ in February to the maximum of 37,959 cells $ml^{-1}$ in May. The species causing massive blooms were Prorocentrum micans Ehrenberg and Ceratium furca (Ehrenberg) Claparede & Lachmann in July, Gymnodinium sanguineum Hirasaka in October, Alexandrium tamarense (Lebour) Balech in April and Proroeentrum minimum (Pavillard) Schiller in May. Twenty-seven taxa of dinoflagellate cysts were isolated, including 20 identified species and 7 unidentified species. The mean cyst abundance ranged from the minimum of 556 cysts $cm^{-3}$ in June to the maximum of 5,727 cysts$cm^{-3}$ in February. The spatial pattern of cyst distribution showed the gradual increase in abundance from offshore to inshore stations. The cyst genera of Protoperidinium, Gymnodinium, Serippsiella, Gyrodinium and Alexandrium were abundant throughout the year. The vertical distribution of cysts showed the surface miximum at the 0-2cm layer and the sub-surface maximum at the 2-4cm layer. Total abundance of cysts showed the most significant relationships with water temperature, and some minor relationship with dissolved oxygen, salinity, pH, phosphate and total inorganic nitrogen of surface and bottom layer in the water column. The number of dinoflagellate species decreased, while the abundance of cysts increased 4.5 times as compared with the observation of 10 years prior to the present study at the same stations of Masan-Chinhae Bay.

• 한국수산과학회지
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• 제40권4호
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• pp.201-209
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• 2007

Line transect sampling in a sighting survey is one of most widely used methods for assessing animal abundance. This study applied distance data, collected from three sighting surveys using line transects for finless porpoise that were conducted in 2004 and 2005 off the west coast of Korea, to four models (hazard-rate, uniform, half-normal and exponential) that can use a variety of detection functions, g (x). The hazard-rate model, a derived model for the detection function, should have a shoulder condition chosen using the AIC (Akaike Information Criterion), as the most suitable model. However, it did not describe a shoulder shape for the value of g(x) near the track tine and underestimated g (x), just as the exponential model did. The hazard-rate model showed a bias toward overestimating the densities of finless porpoises with a higher coefficient of variation (CV) than the other models did. The uniform model underestimated the densities of finless porpoise but had the lowest CV. The half-normal model described a detection function with a shape similar to that of the uniform model. The half-normal model was robust for finless porpoise data and should be able to avoid density underestimation. The estimated abundance of finless porpoise was 3,602 individuals (95% CI=1,251-10,371) inshore in 2005 and 33,045 individuals (95% CI=24,274-44,985) offshore in 2004.

• 수산해양교육연구
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• 제28권4호
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• pp.957-970
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• 2016

This study diagnosed the status of marine environmental impact assessment(MEIA) for project near the habitat of marine protected seagrass species such as Zostera caespitosa, Zostera asiatica, Phyllospadix iwatensis. For the preparation of a marine environmental impact statement, different monitoring parameters are used without any specific guideline for the assessment of current status. And also, both tools and techniques for MEIA are needed to improve for implementing. The monitoring plans and parameters are not considered well with the accuracy of the environmental predictions and effectiveness of any applicable mitigation measures. This study suggested the reasonable standard of the MEIA for the conservation of the marine protected seagrass species which have the habitat located near affected area. The inshore seagrasses need to be monitored including shoot count based on the "No Net Loss of Seagrass" as part of the monitoring parameters to assess the status of marine environment of environmental impact statement. In a process of effect prediction, we suggested a concentration of 10 mg/L suspended solids which added by the new developmental project near seagrasses habitat, referring to study of overseas case. But a further study for an appropriate standard is necessary effectively. In a mitigating process, priority needs to be considered in order of avoidance, minimization, reduction, compensation. In a post-monitoring process, it is necessary to monitor the seagrass species abundance to identify the variation of b/a (before and after) project. And in a case of implementing transplantation, survival rate need to be included to determine a success of project.