• Journal of Environmental Science International
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• v.25 no.10
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• pp.1445-1457
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• 2016

In this study, we investigated the growth of striped mullet (Mugil cephalus), Yesso scallop (Patinopecten yessoensis) and kelp (Saccharina japonica) farmed under the IMTA (integrated multi-trophic aquaculture) system developed by national institute of fisheries science (NIFS). The farmed striped mullets grew from an initial length and weight of $152.5{\pm}12.1mm$ and $41.6{\pm}7.8g$ in October 2013 to $154.2{\pm}5.6mm$ and $47.5{\pm}8.6g$ in November, $160.2{\pm}8.7mm$ and $55.9{\pm}9.1g$ in December and $168.4{\pm}9.6mm$ and $58.4{\pm}8.7g$ in January. The fish continued to grow and reached $190.2{\pm}9.4mm$ in length and $87.5{\pm}8.9g$ in weight in April and $256.4{\pm}9.7mm$ and $156.7{\pm}6.7g$ in October 2014. The daily growth rate (DGR) for total fish length was 0.015~0.1 mm/day during the periods of fast growth and attained 0.038~0.1 mm/day during February ~ March. The kelp grew from an initial blade length and wet weight of $1.19{\pm}0.2cm$ and $0.0028{\pm}0.0012g$ in January 2014 to $3.3{\pm}0.8cm$ and $2.5{\pm}0.9g$ in February and $126.5{\pm}11.6cm$ and $107.4{\pm}22.6g$ in March, after which, erosion occurred and slowed the growth. The DGRs for kelp length ranged 0.03~1.9 mm/day in January 2014 and increased to 0.88~1.9 mm/day during March~April. Increasing water temperatures beginning in April lowered the DGR to 0.03 mm/day. Yesso scallops grew from an initial shell length, shell height and wet weight of $11.83{\pm}0.6mm$, $12.68{\pm}0.7mm$ and in September 2013 to $19.9{\pm}2.5mm$, $20.8{\pm}2.6mm$ and $0.9{\pm}0.04g$ in November 2013. They continued to grow to $45.91{\pm}0.71mm$ in shell length, $42.55{\pm}0.8mm$ in shell height and $12.7{\pm}1.3g$ in wet weight by May 2014 and $60.2{\pm}2.51mm$, $554.6{\pm}2.61mm$ and $24{\pm}2.70g$ by October 2014. The DGRs for shell length of Yesso scallop ranged from 0.02 to 0.256 mm/day with higher values of 0.256~0.27 mm/day during November~December 2013 and March~April 2014.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.2
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• pp.91-108
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• 2018

An ecological study on subtidal macrobenthic fauna was conducted from 25 stations in the estuarine area of Wando-Doam Bay, southern coast of Korea during August 2013. A total of 186 species was collected with a mean density of $1,229ind./m^2$ and a mean biomass of $265.7g/m^2$. Polychaetes showed the richest benthic fauna comprising 43% of total fauna, whereas mollusks appeared as density- and biomass-dominant fauna accounted for 45% and 48% of the mean density and biomass, respectively. The number of species and mean faunal density were relatively higher at the stations surrounded by Sinjido, Joyakdo and Gogeumdo showing a gradual decrease toward inner bay stations. Species number and density were negatively correlated with bottom water temperature, but they were positively correlated with both the bottom salinity and DO. The most dominant species in terms of density was a semelid bivalve, Theora fragilis which showed a positive correlation with TOC content of surface sediment and its high density occurred around Gogeum-Sinji-Joyakdo area where dense aquaculture facilities exist. In the bay mouth area, an amphipod species, Eriopisella sechellensis showed its higher density at the stations with low organic content but fine grains. The combination of water temperature, salinity, pH of bottom water, water and sulfur content of the surface sediment could explain 71% of the spatial distribution of macrobenthic fauna from the Bio-Env analysis. From the cluster analysis, the study area consisted of 6 distinct station groups lineated from offshore area toward inner area. Ampharete arctica, Goniada maculata, Eriopisella sechellensis, Theora fragilis, Caprella sp. were identified as the main contributing faunas in classification by the SIMPER analysis. From the value of BPI, the benthic communities at the inner and central Wando-Doam Bay were assessed to be in a normal condition whereas those at the outer Wando harbor and Gogeum-Sinji-Joyakdo area were assessed in a poor or very poor condition due to the high concentration of particulate organic matter might be originated from the nearby dense aquaculture facilities. This study indicated that pristine inner bay has been influenced by the organic material supplied from the outer bay. Thus it is necessary to establish an ecological management plan to reduce organic enrichment of sediment from dense aquaculture facilities in the outer bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.4
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• pp.204-212
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• 2005

Recognition has emerged that nutrient inputs from the submarine discharge of fresh, brackish, and marine groundwaters into the coastal ocean are comparable to the inputs via river discharge. The coastal areas of the Korea peninsula and adjacent seas exhibit particular importance in the role of submarine groundwater discharge (SGD), in terms of the magnitude of SGD and associated continental material fluxes. For example, in the southern sea of Korea, SGD transports excess nutrients into the coastal regions and thus appears to influence ecosystem changes such as the outbreak of red tides. Around volcanic island, Jeju, which is composed of high permeability rocks, the amount of SGD is higher by orders of magnitude relative to the eastern coast of North America where extensive SGD studies have been conducted. In particular, nutrient discharge through SGD exerts a significant control on coastal ecosystem changes and results in benthic eutrophication in semi-enclosed Bang-du bay, Jeju. In the entire area of the Yellow Sea, tile submarine discharge of brackish groundwater and associated nutrients are found to rival the river discharges into the Yellow Sea, including those through Yangtze River, Han River, etc. In the eastern coast of the Korea peninsula, SGD is significantly higher during summer than winter due to high hydraulic gradients and due to wide distribution of high permeability sandy zones, faults, and fractures. On the other hand, in the estuarine water, downstream construction of the dam in the Nakdong River, SGD was highest when the river discharge was lowest (but water level of the dam was highest). This suggests that even though there is no visible freshwater discharge into this estuary, the discharge of chemical species is significant through SGD. On the basis of the results obtained from the coastal areas of the Korea peninsula, SGD is considered to be an important pathway of continental contaminants influencing tidal-flat ecosystems, red tides, and coral ecology. Thus, future costal management should pay great attention to the impact of SGD on coastal pollution and eutrophication.