• The Korean Journal of Malacology
• /
• v.30 no.1
• /
• pp.57-77
• /
• 2014

The bivalve molluscan fauna of Ulsan Bay, East Sea coast of Korea, is summarized, based on original and literature data. The fauna consists of 61 species belonging to 20 families. Seven species are identified only to genus level. Two species (Carditellopsis toneana (Yokoyama, 1922), Carditidae and Fulvia hungerfordi (G.B. Sowerby III, 1901), Cardiidae) are new records for the East Sea coast of Korea, and one species (Crenella decussata (Montagu, 1808), Mytilidae) is a new record for Korea. Biogeographically, Ulsan Bay's bivalve fauna is subtropical with a predominance of tropical-subtropical species, 21 species, or 39% of the total species number, subtropical, 14 species, or 26%, and subtropical-boreal (mostly subtropical-lowboreal), 11 species, 21%, totalling 86%. A remarkable feature of the Ulsan Bay fauna is the presence of tropical-subtropical species not found in Yeongil Bay but common in tidal flats and shallow waters of the Yellow Sea and the southern part of Korea. A cold water mass appearing off the southeast coast of Korea near Ulsan in summer seems responsible for the presence of boreal-arctic species in this area.

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

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.55 no.3
• /
• pp.252-263
• /
• 2019

In order to understand the tidal current and mean flow at the west channel of Yeoja Bay in the South Sea of Korea, numerical model experiments and vorticity analysis were carried out. The currents flow north at flood and south at ebb respectively and have the reversing form in the west channel. Topographical eddies are found in the surroundings of Dunbyong Island in the east of the channel. The flood currents flow from the waters near Naro Islands through the west channel and the coastal waters near Geumo Islands through the east channel. The ebb currents from the Yeoja Bay flow out along the west and the east channels separately. The south of Nang Island have weak flows because the island is located in the rear of main tidal stream. Currents are converged at ebb and diverged at flood in the northwest of Jeokgum Island. Tidal current ellipses show reversing form in the west channel but a kind of rotational form in the east channel. As the results of tide induced mean flows, cyclonic and anticyclonic topographical eddies at the northern tip but eddies with opposite spin at the southern tip are found in the west channel of Yeoja Bay. The topographical eddies around the islands and narrow channels are created from the vorticity formed at the land shore by the friction between tidal currents and the west channel.

• Ocean and Polar Research
• /
• v.25 no.1
• /
• pp.31-40
• /
• 2003

In August-September 2001, 15 samples of bottom sediments were collected in the inner, middle and open parts of Amursky Bay near Vladivostok, Russia, and barfin plaice Pleuronectes pinnifasciatus was sampled from the inner and the middle locations of the bay. In the sediments from all three sites elevated concentrations of several heavy metals, i.e. Zn ($102-115{\mu}/g$ dry weight), Ni $(70-73{\mu}g/g)$ and Cu $(27-35{\mu}g/g)$ were discovered. The contents of oil hydrocarbons were very close to or slightly higher than the maximal normal environmental background level, $100{\mu}g/g$ dry weight. The sediments contained negligible amounts of hexachlorocyclohexane, while DDT concentrations were quite high (1.7-16.3ng/g dry weight). Generally, there were no substantial differences in the pollution levels of the locations studied and our results resembled those reported for Amursky Bay in the 1990s. Surprisingly, in 2001 'fiesh' DDT comprised 70-85% of the total DDT content in sediment from all the locations studied. In fish liver total DDTs concentrations were 212.8 and 122.54 ng/g wet weight for the inner and the middle locations, respectively, and 'fresh' DDT comprised 35 and 64% of DDTs, respectively. These results provide evidence of recent input of DDT from an unknown source into the ecosystem of Amursky Bay. Histopathological changes revealed in the plaice liver (vacuolization of hepatocytes, coagulative necrosis of hepatocytes, inflammatory reaction, and necrosis of epithelial cells of bile ducts) are probably connected with an intensive metabolism of DDT in the fish organism. No histological and histomorphometric differences were found in the state of the interrenal tissue. Similar condition of the liver and the interrenal tissue in barfin plaice sampled from the inner and the middle locations of Amursky Bay may be explained by the absence of great differences in the pollution levels of these sites.

• Ocean and Polar Research
• /
• v.25 no.2
• /
• pp.155-182
• /
• 2003

An annotated listing of bivalve mollusks collected at 31 sampling sites in Yeongil Bay (eastern coast of Korea) at a depth of 0-52m is presented here. A total of 98 species belonging to 75 genera and 36 families are enumerated; all species are provided with habitat data (bathymetric distribution and bottom sediments character), given separately far living and dead (empty shells) specimens, and some with taxonomic and zoogeographic comments. Fifty-six species are illustrated with photographs. Astarte hakodatensis Yokoyama, 1920 (Astartidae), Nitidotellina pallidula (Lischke 1871) (Tellinidae) and Lyonsia nuculanoformis Scarlato in Volova et Scarlato, 1980 (Lyonsiidae) are found to be new to the Korean fauna, and the genus Salaputium Iredale, 1924 (Crassatellidae) with one species Salapurium Iredale, 1924(Crassatellidae) with one species Salaputium cf. unicum Hayami and Kase, 1993, previously described as being found only from submarine caves in the Ryukyu Islands, is recorded as being found in the East Sea(Sea of Japan) for the first time.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.3
• /
• pp.255-269
• /
• 2023

Surface water temperature of a bay (from the south to the north) increases in spring and summer, but decreases in autumn and winter. Due to shallow water depth, freshwater outflow, and weak current, the water temperature in the central to northern part of the bay is greatly affected by the land coast and air temperature, with large fluctuations. Water temperature variations are large in the north-east coast of the bay, but small in the south-west coast. The difference between water temperature and air temperature is greater in winter and in the south-central part of the bay than that in the north to the eastern coast of the bay where sea dykes are located. As the bay goes from south to north, the range of water temperature fluctuation and the phase show increases. When fresh water is released from the sea dike, the surrounding water temperature decreases and then rises, or rises and then falls. The first mode of empirical orthogonal function (EOF) represents seasonal variation of water temperature. The second mode represents the variability of water temperature gradient in east-west and north-south directions of the bay. In the first mode, the maximum and the minimum are shown in autumn and summer, respectively, consistent with seasonal distribution of surface water temperature variance. In the second mode, phases of the coast of Seosan~Boryeong and the east coast of Anmyeon Island are opposite to each other, bordering the center of the deep bay. Periodic fluctuation of the first mode time coefficient dominates in the one-day and half-day cycle. Its daily fluctuation pattern is similar to air temperature variation. Sea conditions and topographical characteristics excluding air temperature are factors contributing to the variation of the second mode time coefficient.

• Korean Journal of Environmental Biology
• /
• v.34 no.2
• /
• pp.79-90
• /
• 2016

This study investigates seasonal variation and spatial distribution of meiobenthic community of Gamak Bay (one of the major bays of southern coastal area of Korea). Total of 6 surveys of 10 stations took place, once in February, June and October of 2009 and through 2010. Community structure, taxon diversity (H') and nematodes/copepods ratio of meiobenthos were studied in Gamak Bay. During the study period, nematodes and harpacticoids were the most dominant taxa among the meiofaunal groups in Gamak Bay. Taxon diversity (H') was the highest at the outer stations and the lowest at the inner stations in the Gamak Bay. The nematodes/copepods ratio was seasonally studied as an index of pollution monitoring for the benthic ecosystem at each station. As a result, nematodes/copepods ratio was the highest at the inner stations and the lowest at the outer stations in Gamak Bay.

• ALGAE
• /
• v.23 no.4
• /
• pp.251-255
• /
• 2008

In Gamak Bay, Paralytic Shellfish Poisoning (PSP) was first detected from seafoods in 2003, however the toxin source is unknown yet. In this study, we report potential PSP producers of toxic dinoflagellates, describing morphology and abundance of cysts isolated from surface sediment of Gamak Bay. The most abundant type in these cysts was characterized with ellipsoidal and transparent wall identical to Alexandrium catenella and/or A. tamarense. Germination experiment of the cysts revealed that all motile cells germinated were morphologically identified as A. tamarense. This result suggests that A. tamarense may relate to PSP contaminations in Gamak Bay. Moreover, bottom water temperature in Gamak Bay is favorable for germination of A. tamarense cysts. Further studies are required to carry out the PSP monitoring for preventing the risk of PSP events that may outbreak in future at Gamak Bay.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.10 no.1 s.20
• /
• pp.55-59
• /
• 2004

Temperature inversion off Wasaka Bay in the East Sea was studied using data measured on a CREAMS cruise in June of 1995 and 1996. Temperature inversion occurred mainly at the upper layer of the thermocline at a depth of no more than 20 m and around the thermal front between the TWC and the coastal waters of Japan. At some stations. temperature inversion had an influence un density inversion, while, in some other stations, high salinity water prevented density inversion.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.5
• /
• pp.353-362
• /
• 2008

The fish species composition and variation in the Youngil Bay, East Sea of Korea, were investigated every month from January, 2001, to December, 2002, using gill nets for sample collection. A total of 63 fish species belonging to 31 families under 10 orders, and a total of 40 species belonging to 26 families under 8 orders, were identified in 2001 and 2002, respectively. Of these, the families Pleuronectidae (9 species), Scorpaenidae (8 species) and Cottidae (5 species) were dominant in 2001, whereas Pleuronectidae (4 species), Cottidae (3 species) and Hexagrammidae (3 species) were dominant in 2002. The number of species recovered was the highest in August, 2001 (34 species) and January and September, 2002 (14 species each), and lowest in May, 2001 (6 species) and December, 2002 (5 species). The principal component analysis for each year showed that fish species composition differed over time even within the same sample area. In addition, the relationship between PC scores and temperature showed a positive relationship in 2001, but a negative relationship in 2002.