• 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.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.647-658
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• 2018

The aim of this study is to investigate the seasonal changes of phytoplankton communities based on the environmental changes in a dense oyster farming area (Hansan-Geoje Island) from June to December 2016. The water temperature varied from $14^{\circ}C$ to $28.8^{\circ}C$ and its salinity ranged from 29.4 to 34.2 psu. Nitrate+nitrite was kept at c.a. $3.0{\mu}M$ on the surface layer from June to July, below the concentration limit in August and early September, and then gradually increased from late September. Ammonia was high on July 20 and August 10, and its seasonal characteristics were not clear. Phosphate ranged from 0.01 to $0.7{\mu}M$ on the surface layer, and its seasonal changes were similar to those of nitrate+nitrite. Mean silicate concentrations were $10.7{\mu}M$ on the surface and $15.7{\mu}M$ in the bottom layer, and it was not acted as a limiting factor for the growth of phytoplankton. Among the phytoplankton community, Bacillariophyceae, Dinophyceae and Cryptophyceae was 61.2%, 22.5%, and 13.6%, respectively. In late June, dinoflagellate Prorocentrum donghaiense was dominant in the outer waters(St. T1), later on, Cryptomonas spp. and Chaetoceros spp. were dominant, respectively. From late September to October, diatoms Pseudo-nitzschia spp. and Chaetoceros spp. were stimulated under non-stratified condition after the typhoon. In December, A. sanguinea was found to be $1.7{\times}10^5cells\;L^{-1}$. Seasonally, relative high phytoplankton biomass may be favorable to maintain high production of filter feeder oyster in the dense oyster farming areas of Hansan and Geoje Island.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.213-228
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• 2009

This study was conducted to investigate spatio-temporal changes in macrobenthic community structure and benthic environmental conditions in Geoje-Hansa Bay, which is the greatest oyster producing site in Korea. Field survey for benthic environment and macrobenthos was seasonally carried out at 15 stations covering oyster farming sites and non-farming sites from February to November, 2008. The grain size of surface sediments was dominated by very fine silt with the mean phi of about $9\;{\Phi}$ and TOC was 1.9% on average. Mean dissolved oxygen content was 8.1 mg/L and lowest in August corresponding to the 2nd degree in seawater quality criteria. Total species number was 351 and mean density was $3,675\;ind./m^2$, both of which were dominated by polychaete worms. Spatio-temporal variation in above two biological variables was great with higher values seasonally in spring and spatially in channels rather than inner bay. Dominant species were Lumbrineris longifolia (21.3%), Aphelochaeta monilaris (17.8%) and Ericthonius pugnax(6.1%), all of which are typical species of organically enriched area. From the multivariate analyses, the whole macrobenthic community was distinguished into two groups of channel and inner bay group. Spatio-temporal changes of macrobenthic community in Geoje-Hansan Bay were related to those of TOC and acid volatile sulfide (AVS). Our results showed that Geoje-Hansan Bay should be intermediately affected by organic pollution, and that such organic enrichment was more remarkable at farming stations in the inner bay.

• Development and Reproduction
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• v.5 no.2
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• pp.137-144
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• 2001

Gametogenesis and gonadal development of the sea squirt Halocythia roretzi, which is two years old were investigated by histological study. The specimens were collected in Guryong-po coastal area Kyoungsangbuk-do, Korea from May 1996 to April 1997. The sea squirt is hermaphrodite and oviparous. The ovary is located in the inner wall of the tunic year-round, but the testis can be distinguished from in June. The ovary is composed of 6∼8 gonoducts at the left side and 8∼10 ones at the right side, the testis consists of the complex gonad having irregular sacular structures. Oogonia in the ovarian sac were 11.7∼15.6 ${\mu}m$ in diameter. The early developing oocytes were 39.6∼47.6 ${\mu}m$ and nucleus 10.0∼25.0 ${\mu}m$ in diameter. Oocytes in the ovarian sacs during vitellogenesis were 158.6∼210.0 ${\mu}m$, and fully ripe oocytes which were to 210.0∼230.9 ${\mu}m$ in diameter had several test cells in the cortical parts showing a characteristic of vertebrate. The testis showed a general spermatogenesis as in the marine animals. The three-year old sea squirt occurred the first spawning between January to February under 10$^{\circ}C$

• Journal of Environmental Impact Assessment
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• v.29 no.2
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• pp.122-131
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• 2020

Marine Spatial Planning is an emerging strategy that promoting sustainable development at coastal and marine areas based on the concept of ecosystem services. Regarding its methodology, usage rate of resources and its impact should be considered in the process of spatial planning. Particularly, considering the rapid increase of coastal tourism, visitation pattern is required to be identified across coastal areas. However, actions to quantify visitation pattern have been limited due to its required high cost and labor for conducting extensive field-study. In this regard, this study aimed to pose the usage of social big data in Marine Spatial Planning to identify spatial visitation density and critical management zone throughout coastal areas. We suggested the usage of GPS information from Flickr and Twitter, and evaluated the critical management zone by applying spatial statistics and density analysis. This study's results clearly showed the coastal areas having relatively high visitors in the southern sea of South Korea. Applied Flickr and Twitter information showed high correlation with field data, when proxy excluding over-estimation was applied and appropriate grid-scale was identified in assessment approach. Overall, this study offers insights to use social big data in Marine Spatial Planning for reflecting size and usage rate of coastal tourism, which can be used to designate conservation area and critical zones forintensive management to promote constant supply of cultural services.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.115-121
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• 1978

Early developmental stages of Mactra chinensis were bioassayied to determin the water quality of the costal waters of Busan. The water samples were obtained at 12 stations from July 12 to July 17, 1977. Water quality evaluation was made in terms of the rates of normal development to abnormal development in three indicatory states, i. e. fertilization membrane formation, morula and trochophore larvae. The pollution degree of the waters brought from five swimming beaches was found to be highest at Haewundae followed by Songdo, Kwang-anri, Songjeong and Dadaepo with decreasing order. The highest value of the water at Haewundae was mainly due to the accidental oil spill from an oil tanker which happened on July 7, 1977. At Dongsamdong the rate of total abnormal development was $47.17\%$. This result is apparently attributable to fish byproducts discarded from a number of restaurants. At Chungmudong where a large fish-market is located, the rate of total abnormal development was $61.14\%$. At Suyeng Bay and Yongho Bay the rates of total abnormal development were $73.82\%$ and $72.90\%$ respectively. At these bays the drainage presumably contains a large amount of chemical pollutants from the industrial areas. This result shows that no organisms can normally breed in these regions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.380-386
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• 1986

Snailfish, Liparis tanakai (Gilbert et Burke) is widely distributed in the coastal waters of Korea and Japan. On December 21, 1985, fertilized eggs of the fish were collected from the coastal waters of Saryang-do island, Kyongsangnam-do, Korea, and the eggs were incubated and the larvae reared at a mean water temperature of $9.2^{\circ}C$ in the laboratory. The fertilized eggs of this species are demersal, adhesive and spherical in shape, measuring $1.68{\sim}1.78mm$ (mean 1.72mm, n=30) in diameter, containing about 20 oil globules. Hatching took place 21 days after blastula stage. During the incubation period water temperature fluctuated between $8.1^{\circ}C\;and\;11.8^{\circ}C$. The newly hatched larvae were $5.70{\sim}6.41mm$ (mean 6.10mm, n=30) in total length with $7{\sim}9$ (abdominal) and 36 (caudal) myomeres. Many melanophores were distributed on the large pectoral fin, yolk sac and peritoneum. Twelve days after hatching, the larvae attained $5.85{\sim}6.46mm$ in total length, and at this time the larvae absorbed the yolk almost completely. Melanophores appeared on the snout and the posterior part of head.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.869-877
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• 2017

Recently, Gomso Bay saw a decrease in the production of manila clam, which accounted for 17.8 % of production across the whole country in 2015, while Geunso Bay saw an increase that raised its contribution to 49.1 %. The tidal flats in these bays are inhabited by various benthos, and material flows in and out according to the tide. It is essential to understand the mass balance of these regions while giving consideration to the characteristics of these tidal flats. In this study, we compared areas where aquaculture farms were located in Gomso Bay with those without from May to August 2015. We divided the region into three sea areas (Sector I, Sector II, and Control), and the mass balance was estimated using the LOICZ model. As a result, the DIP of Sector II in Gomso Bay and another region in Geunso Bay, where a manila clam farm was located, were found to be -207.2 kg/day and 77.2 kg/day. The DIN was -4,996.7 kg/day and 926.6 kg/day. These results suggest that Gomso Bay han a higher density than Geunso Bay, which is thought to be mainly due to the feeding action of organisms. Therefore, in order to maintain a healthy tidal flat ecosystem and to sustain the production of manila clams, sustainable management to reduce the high density of tidal flat farms is necessary.

• Journal of Appropriate Technology
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• v.5 no.1
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• pp.18-24
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• 2019

Citarum river in West Java, Indonesia plays strategic roles for Jakarta metropolitan areas. Besides it provides major source of water supply such as domestics and drinking water including Jakarta, it also provides water for hundreds of industries through its cascade reservoirs. However, recently, Citarum river basin has been seriously suffering from water and groundwater pollution as well as the lowering-down of groundwater level due to the extreme use of water resources in dry season by domestic and industrial activities. This project objectives are design and installation of industrial wastewater treatment/recycle facilities to overcome the problem of water pollution and the lowering-down of groundwater level in Bandung. For these, cyclone type dissolved air flotation (DAF), CYFLOAT, was successfully installed as the appropriate technology for the target textile industry with 100 ton/day of capacity. The CYFLOAT system can remove the 96.8% of particulates, which are known as a critical factor to recycle the wastewater, within 40 min of residence time. Furthermore, The CYFLOAT system can reduce the operational cost and land use. The project was carried out in strong partnership with local institute including UNPAR, IBT, and PUSKIM for the sustainability of the technology to textile industry complex in Indonesia.

• Development and Reproduction
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• v.13 no.4
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• pp.281-289
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• 2009

The slime flounder Microstomus achne were caught at Geomun Island, Yosu-si, Jeollanamdo from January to March in 2006. The fertilized eggs were observed for morphological development of egg, embryo and larva. Eggs were colorless transparent, separative pelagic, absent of oil globule, and the diameter was 1.64${\pm}$0.03 mm (n=50). The eggs were hatched at 168 hours 40 minutes after fertilization in the range of $9.8\sim13.0^{\circ}C$ (mean $11.4{\pm}1.6^{\circ}C$). Total length of newly hatched larva was 4.05${\pm}$0.18 mm (n=20). The larva had developed membranous fin showing waterdrop-shaped structure, and their mouth and anus were not open. The myotomes were 14~15+33~34=47~49. The egg yolks were 1.64${\pm}$0.12 mm in major axis, and 1.23${\pm}$0.19 mm in minor axis. At 12 days after hatching, the total length was 7.32${\pm}$0.42 mm(n=20). The egg yolk was completely absorbed and transferred to post larval stage. Star-shaped melanophores and branch-shaped xanthophores in the edge of membranous fin were more densed. Chrysanthemum-shaped melanophores in the notochord were densed and formed 4~5 melanophore bands. At 90~93 days after hatching, morphological features of the larva, 19.91${\pm}$1.63 mm TL(n=20), were transferred to juvenile stage showing similar features with those of the adult fish.