• 한국해양학회지
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• v.25 no.4
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• pp.205-216
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• 1990

This study was carried out to investigate the composition and the distribution of the polychaete community in Kwangyang Bay during 1987-1988, and to deduce causal factors of temporal changes in community by the comparison with the results of 1982 (Choi, 1984). In the present study, the Polychaetes comprised a total of 79 species, and had a mean density of 520 ind. $.$m/SUP -2/. They showed high abundance and species diversity in the main tidal channel and the north channel of Myodo. The most abundant polychaete was Lumbrineris longifolia (28.2%), and followed by Nephtys polybranchia (16.3%) and Stermaspis scutata (8.3%). Comparing the polychaete community in summer of 1987 with that in summer of 1982, Lagis bocki and Chone teres, the most dominant species in 1982, disappeared in 1987, while Lumbrineris longifolia, Nephtys polybranchia, Terebellides horikoshii, and Sternapis scutata experienced above twice increases in densities. the community in the north channel was distinguished from those in other regions by the high abundance of L. bocki in 1982, but was similar to that of the main channel by the disappearance of L. bocki in 1987. The community in the western inner bay was similar to that of the main channel in 1982, but became to be distinguished by the disappearance of l. longifolia and the high densities of S. scutata and Tharyx sp. in 1987. The temporal change in species composition and regional difference might be induced by the combined effects in the changes of hydrologic and sedimentary environments owing to the reclamation on the delta of Seomjing River and the dredging of the north chnnel.L.bocki in the north chnnel vanished after the habitat disturbance by the reclamation and dredging.S.scutata and Tharyxsp.dominated in the western inner bay because of the accumulationfo fine sediments through weakenend durrent flow by the obstruction of a new bank constructed on the delta.

• Ocean and Polar Research
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• v.25 no.4
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• pp.519-528
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• 2003

Species composition and community structure of marine benthic community were studied in the intertidal zone of Jijindo Island, Gwangyang Bay. A total of 85 species of benthic marine plants including the 5 Cyanophyta, 9 Chlorophyta, 13 Phaeophyta, 56 Rhodophyta and 2 Magnoliophyta that were listed. The community structure was represented by Gelidium divaricatum in the upper zone, Celidium divalicatum and Ulva pertusa in the middle, and Ulva pertusa, Chondria crassicaulis, Chondracanthus intermedia and Sargassum thunbergii in the lower intertidal zone. The dominant species in the rnscro-zoobenthic community were Chthamalux challengeri in the upper and middle, Littorina brevicula between the upper and middle, and Mytilus edulis and Crassostrea gigas in the middle and lower intertidal zones. The economic benthic organisms such as Undaria pinnatifida, Mytilus edulis, and Crassostrea gigas found in the lower intertidal zone were frequently disturbed due to their collection by local resident. Therefore, it is necessary to record the correct information pertaining to these cases. The species diversity indices estimated kom different sources were quite different. They were 2.22 derived from frequency, 1.67 based on coverage, 2.17 based on sum of frequency and coverage and 2.04 derived from importance value. Species diversity and number of algal species in Gwangyang Bay have noticeably decreased, compared with their previously reported status. It is estimated that their decreases were caused by changes in the marine environment, especially pertaining to the polychaete community resulting from reclamation and dredging activity undertaken for the industrial development.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.430-438
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• 2013

In this study, the seasonal field survey was conducted in Goseong Jaran Bay(22 stations), Geoje Hansan Bay(15 stations) and Jinhae Bay(18 stations). We analyzed the sediment environmental parameters(Chemical Oxygen Demand, Ignition Loss, Acid Volatile Sulfides, Total Organic Carbon) and biotic parameters of macrobenthic polychaetes(number of species, density, diversity, evenness). It had a good correlation between total organic carbon and polychaete diversity(R=0.61, P<0.01), and we made a decision them as representative environmental indices. As a result of that, regarding the criteria in the assessment of farm environment, we suggest concentrations of total organic carbon : Peak Point = 15 mg/g dry, Warning Point = 26 mg/g dry, Contaminated Point = 31 mg/g dry and polychaete diversity : ~2.6(Good), 2.6~2.1(Moderate), 2.1~1.2(Poor) and 1.2~(Bad). This could be a scientific basis to establish the environmental standards for fishery management.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.6
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• pp.793-804
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• 1995

Polychaetous community survey in Tomioka Bay was carried out 5 times seasonally from May 1991 to March 1992 by quantitative grab sampling (0.05m2) at 11 stations. Based on the granulometric composition and environmental factors, a homogeneous soft bottom was found in St.5-10. The species of the polychaete were classified into three feeding groups using the Fauchald and Jumars' feeding guild system. According to polychaetous community composition data, deposit feeders predominate in sandy silt area where the silt-clay content is $60-69.3\%.$ These deposit feeders were subdivided into surface deposit feeders and subsurface deposit feeders by their living position and mode. Also, suspension feeding group comes as the third dominant group. Seasonal changes of each feeding group were described in terms of numerical density and biomass. Feeding layer and types of dominant species (Lumbrineris longifolia: surface deposit feeder; Praxillella pacifica: subsurface deposit feeder; Chone duneri; suspension filter feeder, etc.) were examined in the intact sediment core samples. Also, longterm density change among the three dominant species during 10 years was disussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.35-45
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• 2002

Seasonal quantitative van Veen grab sampling was conducted to characterize the composition and structure of the benthic polychaete community inhabiting the shellfish farming ground of a coastal bay system of Jiniu Bay (Korea). A total of 132 polychaete species were identified and the polychaetes accounted for about $80\%$ of overall abundance of benthic animals. There was little significant seasonal difference in densities (abundances) of polychaetes, Maximum biomass was obseued in summer (August) and minimum value was recorded in winter (February) and spring (May). Conversely, diversity and richness were lowest in summer, indicating a seasonal variability in the polychaetous community structure, The cluster analysis indicated that such a seasonal variability resulted mainly from the appearance of a few small, r-selected opportunists in spring and the tubiculous species of the family Maldanidae in summer. On the other hand, several indicator species for the organically enriched environments such as Capitelia capitata, Notoniashs Jatericeus and hmbrineris sp. showed high densities during all the study period. Density and biomass of univariate measures of community structure were significantly lower in the arkshell-farming ground of the southern area than in the non-farming sites of the bay, A similar general tendency was also found in the spatial distributions of species diversity and richness. Principal component analysis revealed the existence of different groups of benthic assemblages between the arkshell-farming ground and non-farming sites, The lack of colonization of r-selected opportunists and/or tubiculous species in the former ground seemed to contribute to the spatial differences in the composition and structure of the polychaetous communities. Although finer granulometric composition and high sulfide concentration in sediments of the arkshell-farming ground and low salinity in the northern area were likely to account for parts of the differences, other environmental variables observed were unlikely. The spatial distribution of polychaetes in Jiniu Bay may be rather closely related to the sedimentary disturbance by selection of shells for harvesting in spring.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.254-267
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• 2011

In order to assess structure changes of marine benthic communities in the Youngsan River Estuarine Bay for this 10-year period, we sampled macrobenthos in 2006 using the van Veen grab at the same 40 stations where a previous benthic community survey was conducted in 1995. The number of species and mean density of macrobenthos in 2006 decreased significantly than those of 1995. There were no significant differences in both the number and the density of polychaetous species between the two sampling periods, while both number and den-sity of molluscan species decreased significantly. Although the first two density-dominant species, semelid bivalve Theora fragilis and polychaete Tharyx sp. occurred as most dominant species, but the density of T. fragilis decreased significantly in many stations between 1995 and 2006. However, polychaete Tharyx sp. showed increment in density and percentage composition within community. The area dominated by T. fragilis was replaced by Tharyx sp.. Also, polychaete Poecilochaetus johnsoni and bivalve Raetellops pulchella which were pre-dominant in 1995 decreased significantly by 2006. Bivalve Yoldia johanni decreased its density and reduced its distribution area by 2006. Species diversity and rarefaction curves also revealed that overall species richness decreased. These results confirmed that the dominant species and species diversity of macrobenthic communities in the area should be changed due to anthropogenic stresses during 10 years.

• 한국해양학회지
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• v.22 no.4
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• pp.257-270
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• 1987

Fouling communities developing in Jinhae Harbor and Masan Bay were studied by slide and panel immersion test during the period from Dec., 1982 to Nov., 1983. The total viable count of bacteria was estimated more than 1.7${\times}$ 10$\^$4/CFU/$\textrm{cm}^2$ after 15 days of immersion and 46 taxa of benthic diatoms were classified in micro-community. Progressional change of fouling communities was clearly shown and dominant diatom species are Licmophora flavellata, Navicula grevillei, and Nitzschia closterium Major macrofouling organisms are Mytilus edulis, Balanus amphitrite amphitrite, Hydroides ezoensis, and Celleporina sp. Wet weight production of macrofouling organisms exceeds 500g/100cm$\^$2/ after 5months of immersion. Regional defferences in community development are clearly shown in two study areas, and mainly due to the disparities of physicochemical stability and nutritional status of ambient water. Seasonality of larvae and the growth rate are the important factors in fouling community development. Overall process of community development is as follow : bacteria and diatoms-multicellular algae-barnacle, mussels and polychaete-sponge, anemone and ascidian.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.101-113
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• 2003

The spatial distributional pattern of macrobenthic fauna was investigated to assess the summer benthic environmental conditions in Gwangyang Bay, the southern coast of Korea. The macrobenthic faunal community from 38 sites in Gwangyang Bay comprised 154 species and showed an overall mean density of 1,280 individuals $m^{-2}$. Polychaetes were the most important component of the macrofaunal community in species richness, abundance and biomass. The dominant species in abundance were polychaetes like Tharyx sp. (44.8%), Lumbrineris longifolia (14.0%), Heteromastus filiformis (3.6%), a mussel Mytilus edulis, and an amphipod crustacean Corophium sinense. The abundance and biomass in the western part of the bay were lower than those in the channel regions and mouth of the bay. The community indices showed the same trend in the spatial distribution with the abundance and species richness. All macrobenthic faunas were assigned into a specific functional group according to their ecological responses to the environmental stress. The benthic community health based on the Benthic Pollution Index (BPI) or Biotic Coefficient (BC) seemed to be in the normal to unbalanced er transitional condition, indicated by the dominance of small polychaete worms like Tharyx sp. in the mouth part of the bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.3
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• pp.112-124
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• 2016

In order to see the spatio-temporal distribution patterns of macrobenthic fauna in subtidal areas of Nakdong River estuary, benthic fauna samples were collected seasonally at 8 sites in subtidal areas of Nakdong River estuary from February, 2013 to November, 2015. Sandy sediment facies was found in the southern part of the barrier islands in Nakdong River estuary while muddy sediment facies occupied at sites in offshore areas. The bottom salinity of the study area was measured greater than 30 psu during the study period. The mean species richness and density were estimated as 266 species and $859ind\;m^{-2}$, respectively. Polychaete worms were the most abundant fauna group, and four polychaete species such as Goniada maculata, Sternaspis chinensis, Magelona japonica, and Heteromastus filiformis occurred as dominant species in this study area. Pseudopolydora kempi known as an opportunistic species occurred dominantly only in August, 2013. From the multivariate analyses, the macrobenthic fauna in the subtidal area of the Nakdong River estuary could be divided into 2 assemblages that each occupied sites near barrier islands and offshore areas by sediment facies.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.735-745
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• 2022

In this study, a health assessment was conducted using the Benthic Health Index (BHI) to assess fish cage farms, where a fishery environment assessment was also performed. A total of 43 farms were evaluated located in the East Sea, West Sea, and South Sea in Korea. The results of the BHI health evaluation included 8 grade 1 farms, 4 grade 2, 12 grade 3, and 19 grade 4. The grade 1 farms included sandy sediment farms and those with low intensity aquaculture, while the grade 2 farms included those located in areas with active seawater circulation. The fish cage farms belonging to grade 3 and 4 included the majority of farms with high-intensity aquaculture activities. There was no significant difference in total organic carbon between grade 3 and 4 farms, but the results of polychaete community analysis show that organic matter concentration was significantly higher in grade 4 farms.