• Ocean and Polar Research
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• v.38 no.2
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• pp.115-128
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• 2016

This study examined the relationship between macrobenthic distribution patterns and environmental factors in salt marsh vegetation in Donggeomdo, Ganghwa on the west coast of Korea. Nine stations were fixed on a transect across the salt marsh vegetation, and field sampling was carried out monthly from July 1997 to June 1998. A total of 38 species of macrobenthos were recorded: each of faunal groups, 13 (34.2%) Arthropoda, 12 (31.6%) Polychaeta, 8 (21.1%) Mollusca, and 5 (13.2%) others. The mean density was $2,659individuals/m^2$, with a mean biomass of $178.6gWWt/m^2$. Mollusca dominated in terms of abundance and biomass, with a mean density of $2,172individuals/m^2$ (81.7%) and a mean biomass of $131.9gWWt/m^2$ (73.9%). The number of species decreased in winter (January-February), while mean density increased in the spring (May-June). The biomass was relatively in Summer and Fall (July-November), than any other season. The number of species was high in pure stands of Suaeda japonica in the lower salt marsh vegetation, and the mean density and biomass were high in mixed halophyte communities in the middle salt marsh vegetation. Two Mollusca, the bivalve Glauconome chinensis and gastropod Assiminea lutea, were dominant. The densities of these two species were high in mixed halophyte communities in the middle salt marsh vegetation. Non-metric multi-dimensional scaling (nMDS) showed that the study area could be divided into four groups corresponding to the vertical distribution of tidal levels and halophytes. Spearman's rank correlation revealed that the distribution patterns and community structure of macrobenthos were related to environment variables such as salinity of the substrates, exposure time, and grain size compositions of the sediment in the salt marsh vegetation. Particularly, the distribution and density of some dominant species showed differences along the vertical distributions of halophytes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.167-182
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• 2021

This study was carried out to investigate temporal and spatial distribution of macrobenthic community and elucidate effects of environmental factors on change of community structure in an intertidal flat, Hakseong-ri, Boryeong, Korea. Field surveys were seasonally conducted to collect samples of sediment and macrobenthos using can core in triplicate at nine stations in 2016 and 2017. Our results showed that sediment had high mud content (above 60%) in most samples and mean content of loss on ignition was 2.3% in 2016. A total of 79 species was collected in the study site during the study period. Mean density and biomass were 611 ind./m² and 64.1 gWWt/m², respectively. Heteromastus filiformis was the dominant species (48.6%, 297 ind./m²) followed by Macrophthalmus japonicus (10.1%, 62 ind./m²) and Upogebia major (6.9%, 42 ind./m²). Three assembly groups resulted from cluster analysis were more distinguished by interaction between organisms and frequency of dominant species than by physical and chemical environment characteristics. In addition, macrobenthic community in the Hakseong intertidal flat showed seasonal changes based on non metric multidimensional scaling using species abundance.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.4
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• pp.143-157
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• 2023

This study confirmed the characteristics of macrobenthic community due to anthropogenic environmental changes in the Boryeong Jugyo tidal flat, where the habitat of manila clam (Ruditapes philippinarum) and mud shrimp (Upogebia major) is separated. The total number of occurring species was 55 during the study period with an average habitat density of 338 ind./m² and a biomass of 212.2 gWWt/m². The number of occuring species increased from 27 species at the upper flat to 37 species at the lower flat, and the dominant species differed by tide levels (Upper: Leonnates persica, Middle: Heteromastus filiformis, Lower: R. philippinarum). The macro-benthic community sturctures of the top 10 species using cluster analysis and nMDS were divided into two groups, focusing on Manila clam culture farm of lower flats and middle flats with high habitat density, reflecting the influence of specific species. The sediment composition of the U. major habitat space fluctuated highly, but it was maintained annually, and the sorting coefficient was 2.1 𝜑, and the proportion of the same particle size was increased. In particular, because the middle flat has a dense anthropogenic impact, a dominant species, H. filiformis dominated and revealed a relationship with the density of burrow holes of U. major, which is considered to be a biological interaction between these two macrofauna in this tidal flat.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.262-272
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• 2007

Diurnal and tidal variation in the abundance of the macro- and megabenthic assemblages were studied in the macrotidal flat, Incheon, Korea. The samples were collected by modified otter trawl during 8-9, June 2000. The macro- and megabenthic assemblages comprised a total of 60 species, including 6,309 individuals and 67,835.5 gWWt. As a result, the abundance pattern showed two different categories relating to diel and tidal cycles. First, the diel pattern of these assemblages was subdivided into 3 groups. 1) Diurnal species such as Hexagrammos otakii, Thryssa baelama, Loligo beka, Metapenaeus joyneri. 2) Nocturnal species such as Cynoglossus joyneri, Sebastes schlegeli, Charybdis japonica, Crangon affinis, Trachysalambria curvirostris, Metapenaeopsis dalei. 3)Other species showing no obvious pattern with Johnius grypotus, Platycephalus indicus, Repomucenus richardsonii. However, based on the result of Mann-Whitney U-test, diel patterns of macro- and megabenthos did not reveal any significant differences. Second, tidal variation in the macro- and megabenthic assemblages was significant between ebb and flood tides. Total macro- and megafaunal species number, abundance and biomass were higher in ebb tide$(13^h30',\;16^h30',\;1^h30',\;4^h30')$ than in flood tide$(19^h30',\;21^h30',\;10^h30',\;13^h00')$. As a consequence, the macro- and megabenthic assemblages were clearly influenced by tides but their diel variations were not significantly different.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.510-520
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• 2010

This study investigated the community structure and seasonal variation of the fish assemblages on Jangbong tidal flat, Incheon, Korea. Fish were collected monthly using a small otter trawl from November 1999 to January 2001. Thirty-six fish species were recorded, with a mean density of 185 individuals and biomass of 2,594.3 gWWt. The most abundant species by number were Johnius grypotus (23.7%), Acanthogobius hasta (17.8%), and Cynoglossus joyneri (10.7%), while the dominant species by catch weight were Acanthogobius hasta (21.2%), Sebastes schlegeli (16.2%), J. grypotus (14.0%), and C. joyneri (10.8%). Cluster analysis and non-metric multi-dimensional scaling (nMDS) were applied to assess the seasonal fluctuation in the fish assemblages. Based on the result of the cluster analysis and nMDS ordination, the faunal group could be divided into cold- and warm-water specialist groups. The cold-water specialists included A. hasta, Acanthogobius luridus, Triaenopogon barbatus, Tridentiger trigonocephalus, and Liza haematocheila. The warm-water specialists were J. grypotus, C. joyneri, S. schlegeli, and Hexagrammos otakii. In conclusion, the community structure showed a distinct seasonal trend, which seemed to be related to the seasonal fluctuations in water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.521-531
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• 2010

This study examined the community structure and temporal variation of the macro-crustaceans on Jangbong tidal flat, Incheon, Korea. Macro-crustaceans on this tidal flat were collected using a modified otter trawl from November 1999 to January 2001. The macro-crustaceans comprised 32 species, 7,741 individuals, and 29,211.3 gWWt during the study period. The Jangbong tidal flat was dominated numerically by three shrimp (Palaemon carinicauda, Crangon affinis, and Metapenaeus joyneri) and two portunid crabs (Charybdis japonica and Portunus trituberculatus). The macro-crustacean assemblages were divided into two different season and species groups based on the q-mode and r-mode clustering methods. In terms of q-mode, they consisted of a winter species group from December through April and a summer species group from May through November. The r-mode analysis showed that the species group visiting the tidal flat in winter was dominated numerically by palaemonid and crangonid shrimps, while a species group characterized by an abundance of portunid crabs and penaeid shrimps was more frequent in spring, summer, and autumn. In conclusion, our study revealed distinct temporal variation in the tidal flat use by macro-crustaceans around Jangbong Island, Incheon, Korea.

• The Korean Journal of Malacology
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• v.20 no.1
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• pp.45-53
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• 2004

This study have conducted to calibrate the productivities on the mussel (Mytilus galloprovincialis) cultures in Jinhae Bay. Annual water temperature, salinity and dissolved oxygen have varied to 7.2-$25.9^{\circ}C$, 32.9-34.0 psu, 7.9-8.7 mg/l, respectively. In April, the smallest size of spat, 3.3 mm in shell length, have recruited, and 82.5 mm have recorded to the maximum. In summer, variations of growing up between individuals showed both shell length and weights at same cohort. Annual production at 2 m, 5 m, 8 m depth calculated to 10.91, 10.85 and 9.19 gWWt/ind./yr, respectively. Mussel cultivated in the upper part of the water column (two meter depth) were significantly longer and heavier than those in lower part (eight meter depth). After the recruitment, monthly production showed gradual increment at all positions during summer. As results, annual production of mussel cultivated seemed to be controlled by conditions of growing up in summer. Based on the productivities calculated to this study, the total annual production of the mussel cultivated in Jinhae Bay have estimated about 196 ton/ha/yr.

• Ocean and Polar Research
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• v.26 no.2
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• pp.311-321
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• 2004

Relationships between sedimentary environments and abundance of benthic animals were examined on the deep-sea floor, the Clarion-Clipperton Fracture Zone, in the northeast equatorial Pacific Ocean. Specimens were collected using a box corer at 8 stations by sieving through 0.3 mm mesh screen. Sediments showed finer grain size ranged from 5.63 to $7.97{\varphi}$, 83.1% of mean porosity, 1.81 kPa of mean shear strength and organic carbon content in sediment ranged from 0.97 to $1.87\;mg/cm^3$. Manganese nodules covered on the bottom layer from 4 to 57% of coverages. A total of 26 faunal groups in 6 phyla was sampled and comprised 1,467 individuals. Mean biomass were calibrated to 0.5 gWWt/$0.06\;m^2$. Small-sized animals including foraminiferans and nematods were dominated among the faunal group which comprised 49.1% (892 ind.) and 11.5% (320 ind.), respectively. In SPI-analysis, vertical bio-disturbance marks were not observed except to Beggiatoa-type bacterial mats. As the results of relationship between environments and benthos, abundance of benthic animals, especially nematode, showed only a negative correlation to the coverage of nodules, and any other sedimentary factors analyzed in this study were rarely affected to the spatial distribution of benthic animals.

• Ocean and Polar Research
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• v.27 no.2
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• pp.135-148
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• 2005

Macrobeilthic fauna were collected using a van Veen grab $(0.1m^2)$ to investigate the spatial characteristics of the macrobenthos community at 28 stations near the Nakdong River estuary, Southeast Korea, in September 2001. A total of 203 species were sampled with a mean density of $1,554 ind./m^2$ and a biomass of $252.3 gWWt/m^2$. Annelids were the dominant faunal group in terms of species and density, with 68 species and a mean density of $1,031ind./m^2$, which comprised 33.5% and 66.3% of the total benthic animals, respectively. Based on density, three Polychaetes were dominant Tharyx sp· $(420ind./m^2)$, Lumbrineris longifolia $(143ind./m^2)$, and Sternaspis scutata $(118ind./m^2)$, along with a bivalve Theora fragilis $(129 ind./m^2)$. On cluster analysis, the benthic community was classified into four groups based on the species composition: Group-1 occurred in disturbed areas, Group-II in coastal regions, Group-III in central mariculture grounds, and Group-IV offshore. Environmental factors (mean gain size, organic carbon, and depth) were primarily correlated with the macrobenthos community structure. A benthic pollution assessment based on the macrobenthos community structure showed that Group-I and Group-II were located in a coastal area that had been severely disturbed by construction of Busan new port and various pollutants, Group-III was gradually polluted, while offshore Group-IV was the most stable.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.2
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• pp.146-156
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• 2000

Zonation pattern of macro-invertebrate community structure was examined from Okjukpo sandy beach, Taechongdo, Korea. Macrofauna were collected in June 1998 using a can corer from ten stations along one transect. Mean grain size ranged from 1.97 to 2.23${\phi}$ and sediment organic contents ranged from 0.52 to 1.02%. A total of benthic macro-invertebrates comprised 25 species, providing 10,705 individuals and 89.13 g wet weight in biomass. Peracaridean crustaceans such as amphipods and isopods are the most prominant components in this exposed sandy beach. The dominant species were Eohaustorius setulosus (33%), Excirolana chiltoni (26%), Haustorioides koreanus (12%), Platorchestia crassicornis (8%), and Cycladicama cumingii (6%). The zonation patterns by these animals were very similar to those noted by Dahl(1952) and Jo(1990). They are divided into three faunal zones: 1) subterrestrial fringe dominated by a talitrid amphipod Platorchestia crassicornis, 2) midlittoral zone by a cirolanid isopod Excirolana chiltoni, 3) sublittoral fringe by more diverse amphipods communities.