• Animal Systematics, Evolution and Diversity
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• v.35 no.2
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• pp.57-62
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• 2019

Eutima japonica Uchida, 1925, a bivalve-inhabiting hydrozoan was collected for the first time in Korea, associating with Mytilus galloprovincialis. The morphology of male medusae of this hydrozoan is clarified by culture and described as well as other developmental stages. As the present material from Korea is in good accord with that of the northern Japanese form of E. japonica, so the geographical distribution of the northern form of this species is widened, Japan, China and Korea. Green fluorescent protein distribution pattern of this medusa is also described and compared with that of the most related species Eutima sapinhoa Narchi and Hebling, 1975.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.297-305
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• 2009

The Asian paddle crab, Charybdis japonica (A. Milne-Edwards) is an important fishery resource in Korea. Despite its common occurrence and commercial importance, few studies have been carried out on the life cycle and trophic ecology of these populations inhabiting on the tidal flat. Food habits of C. japonica populations were investigated on the Jangbong tidal flat, Incheon, Korea. Monthly samples were taken using a modified otter trawl from November 1999 to January 2001. Based on the examination of stomach contents from 257 individuals, the frequencies of occurrence and the relative volumes of food items were analysed. As a result, the crustaceans (the brachyura, the cirripedia and the harpacticoid copepoda), the echinoderms (the ophiuroidea) and the molluscs (the cephalopoda Loligo beka, the bivalves Bivalvia unid. and Mytilus galloprovincialis) were important food for this species. To examine ontogenetic shifts in diets, individuals of C. japonica were categorized into 2 different size classes (${\leq}60mm$ and ${\geq}61mm$ in carapace width) representing sexually premature and mature stages. The food items of the small crabs (${\leq}60mm$) were dominated by the crustaceans with the harpacticoid copepods constituting 84.6% of total prey number. The next group was the bivalves and the brachyurans. On the other hand, the large crabs (${\geq}61mm$) mainly feed on the bivalvia (Mytilus galloprovincialis and Bivalvia unid.), the brachyurans (Crab unid.) and occasionally the cephalopods and fishes. The difference in proportions of the main prey items among these two size classes was statistically significant. Therefore, the feeding habits of the portunid crab, C. japonica changed with growth.

• 한국해양학회지
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• v.23 no.3
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• pp.123-129
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• 1988

The toxicity of bivalves in the Korean waters was investigated during 1987-1988. The toxicity of paralytic shellfish poison (PSP) was found in the sea mussels (Mytilus edulis galloprovincialis, M. corsucus), scallops (Patinopecten yessoensis, Chlamys farreri), tellin (Peronidia venulosa) and venus clam (Ruditapes philippinarum) among the 28 species screened. The toxicity in mussels, scallop (C. farreri) and venus clam was mainly confirmed from the samples collected around Jindong Bay in the southern coast of the peninsula, whereas the toxicities of tellin and scallop (P. yessoensis) were found in the vicinity of Pohang in the east coast. Samples from the west coast showed low levels of toxicity than those from the east arid south coasts. Although it varied with the regions, the toxicity was detected mainly during April to June, exceptionally during May to August in Pohang. The levels of toxicity were generally below the criteria of 4 mouse unit (MU)/g edible portion in foreign countries, with few exceptions.

• Ocean and Polar Research
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• v.40 no.2
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• pp.59-67
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• 2018

This study was conducted to understand the distribution and changes of macrobenthos on rocky intertidal areas around Taean thermoelectric power plant, Also, the purpose of this study was to produce a base-line data on the changes in water temperature due to the operation of the power plant and to understand its thermal impact on the macrobenthic community on intertidal rocky bottoms. A field survey was seasonally conducted at 3 rocky intertidal sites around the Taean thermal power plant. There was no seasonal difference in the community parameters such as number of species, mean density, biomass and species diversity during the study period. The major dominant species were Chthamalus challenger, Littorina brevicula, Crassostrea gigas. In comparison with previous study, thermal discharge in the study area did not significantly affect the distribution of dominant species. The structure of the macrobenthic community revealed that there were showed 3 different faunal groups depending on the difference in the mean density of major dominant species. The result of SIMPER analyses to determine which species were the main contributors to the differences between each community, C. challenger, Lottia spp. And Mytilus galloprovincialis, etc., revealed that there was showed a significant difference between each group. The abundance of M. galloprovincialis, showed a significant difference between faunal groups.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.500-508
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• 2003

The fauna associated with mussel (Mytilus galloprovincialis) beds and vertical distribution of macrobenthos were studied on the Goijeong rocky shore in Jinhae Bay, Korea. Sampling was conducted seasonally using a quadrate from January to October, 1998. In the first experiment, to reveal the community structure of macrobenthos in mussel bed, a total of 62 species $(10,690ind./m^2,\;3,802.1\;g/m^2)$ were identified, which included polychaetes $(32\;spp.,\;52.6\%),$ molluscs (16 spp.), crustaceans (10 spp.), and others. The density-dominant species were Pseudopolydora antennata, Nereis heterocirrata, Littorina brevicula and Balanus kondakovi. And the density of associated fauna was correlated with that of mussel (r=0.951, p=0.049). In the second experiment, to reveal the vertical distribution of macrobenthos on the rocky shore, ANOVA showed highly significant differences between the density of top 5 dominant species (Chthamalus challengeri, Littorina brevicula, Balanus kondakovi, Septifer virgatus and Granulilittorina exigua) and tidal levels (P=0.000). Vertical distribution of macrobnethos was characterized by Ghthamalus belt and Balanus-Septifer belt in the mussel bed.

• The Korean Journal of Malacology
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• v.27 no.2
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• pp.99-105
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• 2011

This study was conducted to compare the species composition of sessile organisms on the artificial substrates of PVC submerged at different time intervals and duration in Jangmok Bay, Geoje Island, southern coast of Korea. Three PVC plates were submerged at one month interval from March to October and retrieved in November, 2007. A mussel, Mytilus galloprovincialis exclusively occupied the artificial substrates submerged from March to April and occurred as a dominant species to July. An ascidian, Styela plicata occurred as a dominant sessile species from May to August. Balanus amphtrite, Bugula sp., and hydrozoans occurred as dominant species on the plates submerged from July to September. There was a mis-match between the peak time of settlement and dominance of sessile organisms due to the interspecies competitions when the PVC plates were retrieved in November. There was no clear relationship between submerged duration and the abundance of sessile organisms due to the different settlement period. M. galloprovincialis seemed to be a strong competitor which could exclude the previous recruiters of macroalgae by overgrowth and occupy the substrate surface and maintain its high population density by preventing the settlement of other species until late autumn. These results suggested that the composition of sessile organisms in vacant hard substrates could be determined by the combined effects of supply-timing of larvae and post-settlement competitions.

• Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.76-82
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• 2005

We analyzed the paralytic shellfish poisoning (PSP) toxins of the toxic marine dinoflagellate Alexandrium tamarense collected from Dadaepo and Gaduck-do in Busan and from Sujeong-ri in Jinhae Bay, Korea, in April 2003. We also analyzed the PSP toxin of mussels (Mytilus galloprovincialis) and oysters (Crassostrea gigas) collected around Busan and Jinhae Bay. PSP toxin analyses were conducted by high performance liquid chromatography (HPLC). Fifteen cultured A. tamarense isolates contained 2.78 to 57.47 fmol/cell, with nearly identical toxin profiles: major components C2, GTX4; minor components C1, GTX1, NEO; and trace components GTX2, GTX3, STX. PSP toxin contents were 0 to $492\;\mu{g}$ STXeq/100 g in mussels and 0 to $48\;\mu{g}$ STXeq/100 g in oysters. Mussels at Gijang and Sujeong-ri contained the most PSP toxin contents ($492\;\mu{g}\;STXeq/100\;g\;and\;252\;\mu{g}\;STXeq/100\;g,\;respectively$), exceeding the quarantine level ($80\;\mu{g}$ STXeq/100 g). Their dominant toxin components were C2, C1, GTX2, and GTX3; the minor components GTX1, GTX4, GTX5, and NEO were sporadically detected. Phytoplankton contained 0.774 fmol/L seawater and 1.228 fmol/L seawater at Gijang and Sujeong-ri in April. At that time, Alexandrium cells were present in the water column at Gijang at 2,577 cells/mL and at Sujeong-ri at 6,750 cells/mL. Overall, we found the high and similar PSP toxin contents in AZexandrium isolates and mussels, and a correlation between occurrence of toxic Alexandrium cells in the water column and mussel intoxification. High densities of toxic Alexandrium cells in the water column immediately preceded shellfish intoxification at Gijang and Sujeong-ri in April.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.71-84
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• 2007

Masan Bay is a representative semi-closed bay acted as a sedimentation reservoir with a slow current velocity and a poor water circulation in Korea. The pollutants from terrestrial sources into the Masan Bay have apparently environmental pollution problems, such as eutrophication, red tied, and hypoxia. In this study, An ecological modeling work was performed to estimate the material circulation including the growth of bivalve in ecosystem. Furthermore, the effect of water purification was calculated by filter feeding bivalve to particulate organic matter just like COD and phytoplankton. And Water quality management strategy by bio-purification of bivalve is derived through selection of location, quantification of bivalve aquaculture farm. The results showed that the optimum location for bivalve farming is where phytoplankton accumulation by physical processes is maximized and the optimum density and area of bivalve are 35 individuals $m^{-3}$ and ca. 500 hectare, respectively. When assuming conditions for the optimum growth of bivalve, COD could decrease by up to 18% even without other reduction of pollution loads.

• The Korean Journal of Malacology
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• v.22 no.1 s.35
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• pp.63-86
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• 2006

A list of species of bivalve mollusks, their local distributions and relative abundance in Yeongil Bay were analysed. Species richness ranging from 1 to 37 species was low (less than 10) in some stations at the entrance and in the central part of the bay. Fifteen species (Acila insignis, Nucula tenuis, Yoldia notabilis, Mytilus galloprovincialis, Arca boucardi, Axinopsida subquadrata, Felaniella usta, Mactra chinensis, Raeta pulchella, Nitidotellina hokkaidoensis, Theora fragilis, Alvenius ojianus, Callithaca adamsi, Ruditapes philippinarum and Laternula anatina) were most frequently encountered, and seven of them were most abundant numerically (per sample): Th. fragilis in the inner bay, A. insignis, N. tenuis, and A. ojianus in the outer bay, and C. adamsi, A. subquadrata, R. puichella in both parts. Local distributions of common species were described and presented in plotted data, and three distribution patterns were recognized. Biogeographical analysis shows that a majority of species (55%) belongs to the subtropical group, tropical-subtropical species (16%) play a relatively significant role, and the percentage of boreal (temperate) and boreal-arctic species is 18% which characterizes the whole fauna as subtropical. Zonal-biogeographical composition and number of species in families in Yeongil Bay are compared with those of some Japanese (Wakasa and Mutsu) and Russian (Peter the Great, Possjet and Amursky) bays of the East Sea. The absence of a number of typical warm-water embaymental mollusks in Yeongil Bay found in the north further East Sea and Japan, and the similar zonal-biogeographical structure of the inner and outer bay faunas are explained by active water exchange due to the openness of the bay, relatively low summer temperatures, and presence of upwelled cold waters.

• Ocean and Polar Research
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• v.43 no.4
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• pp.255-267
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• 2021

To understand the composition and community changes of benthic species by water depth (5 m, 20 m, 30 m) in the cage facilities, net substrate made of fish cages were installed at intervals of 2 months from March to September 2019, which is the main period of sessile organism recruitment. Water temperature and salinity varied in the ranges of 1~5℃ and 1~4 mg/L at 5 m from June to August, respectively, and less difference was observed according to water depth in other investigation periods. A total of 37 benthic animals were recruited, and Kamptozoa unid., Caprella scaura and Jassa slatteryi were verified during the entire study period. Mytilus galloprovincialis, a Mediterranean mussel, showed seasonality dominant only from spring to early summer (March to July). The community structure classified by temporal and spatial factors, and Bugula neritina, Kamptozoa unid., and Sertularella sp. contributed to the formation of the community. The depth of 5 m was exposed to environmental changes in water temperature and salinity temporally, so there was a seasonal variation in the composition of the sessile organism, but at depths of 20 m and 30 m, there was less significant environmental change and it showed relatively stable than 5 m.