• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.351-358
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• 2016

The aim of this study was to verify the performance of Teleaulax amphioxeia as prey for Brachionus plicatilis and for the larvae of the bivalves (Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum) to select the best of five T. amphioxeia strains. The five strains of T. amphioxeia were collected from the coasts of Korea, purecultured and then fed to the rotifer and bivalve larvae. The density and fecundity rate of the rotifer fed on strain 01 were the highest. The instantaneous growth rate of the rotifer fed strain 08-2 was the highest. The maximum density and fecundity rate of the rotifer fed strain 08-2 were significantly higher than those fed Chlorella ellipsoidea, while instantaneous growth rate showed the opposite pattern. Survival rates of the Manila clam larvae fed each strain of Teleaulax showed no significant difference between strains. Survival rates of the Pacific oyster fed Teleaulax were significantly higher than those fed Chaetoceros sp., but lower than those fed I. galbana. This study indicates that strain 08-2 showed better growth for B. plicatilis and better survival for the bivalve larvae than did the other strains, and that T. amphioxeia can also be used as a prey organism for rotifers or bivalve larvae.

• 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.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.349-354
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• 2014

The diet composition of bullet mackerel, Auxis rochei was studied using 200 specimens collected from December 2013 to May 2014 in the coastal waters of Iloilo, Philippines. The size of A. rochei ranged from 11.1 to 31.2 cm in fork length (FL). A. rochei was epipelagic feeder that consumed mainly fishes. In addition, A. rochei consumed shrimps, copepods, crab larvae, amphipods and cephalopods. The diet also included small quantities of stomatopods, bivalves, and ostracods. Also, analysis of the prey-specific abundance against the frequency of occurrence shows that A. rochei have a narrow food niche, and are specialized feeder with fish as their dominant prey. Although fishes were the primary in food consumed by all size class. The fishes gradually increased with body size.

• 한국해양학회지
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• v.1
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• pp.49-55
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• 1971

After the heavy precipitation from April 1969 to September 1970, more than 1.359 10$\^$6/㎥ of fresh water was discharged through diversion channel of the Namgang Dam. The sands and muds in the northern Sachon Bay were moved and swept away by the strong southsard flow which was observed to be speedier than five knots. The shellfish culture facility as well as the oysters and bivalves were buried. In Sachon Bay, a southward surface ebb current of approximately one knot stratifies above the northward flow of approximately 0.5 knot, which seems to be similar to the salt wedge estuary. The stratified current is responsible for the breaking of the gill nets and other fishing gears. The salinity of sea water in Chinju Bay decreased remarkably and the abnormal low salinity water lower than 5 was distributed in Sachon Bay. The low salinity water front was observed in eastern Chinju Bay and the Samchonpo Channel, where the salinity was increased from 4.6 to approximately 30 within half a tidal cycle. These caused the oysters and bivalves die, and drove anchovies and octopus out to the sea and prevented them from approaching the bay. The decrease of salinity causes the decrease of density and osmotic pressure of sea water. Turbid water would prevent the sunlight from penetrate into deep layer.

• The Korean Journal of Malacology
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• v.29 no.4
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• pp.377-380
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• 2013

This study investigated concentration of metal ions in sediment and intersexuality in Polymesoda erosa and Lutraria lutraria. Samples were collected from five areas of Ha Long Bay in October, 2012. The concentration of metal ions showed that Al ($37390.0{\pm}11816.5mg/kg$) was highest and Mn ($360.4{\pm}101.4mg/kg$) was second high concentration. Cd ($0.04{\pm}0.05mg/kg$) was lowest. The intersexuality was 14.3% in P. erosa and 9.1% in L. lutraria that observed only in female.

• The Korean Journal of Malacology
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• v.10 no.2
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• pp.41-46
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• 1994

The Antarctic soft-shelled clam, Laternula elliptica is widely distributed in shallow waters around the Antarctic Continent and islands. This bivalve species occurs in densepatches particularly in sheltered but frequently ice-impacted areas. This species mostly occurs at atound 20-30 m depth and is rarely found at depths shallower than 5 m where ice abrasion by drifting or grounded icebergs is severe. It burrows deep into sedimint(frequently >50 cm), which seems to be primarily a means for avoiding ice impacts. A pair of stout and highly extendable siphons appear to be a morphological reature to feed in the ice-scoured substrates while staying deep in the sedimint. As one of the largest bivalves in the Antarctic waters, L. elliptica appears to grow rapidly, reaching to a shell length of approximately 100 mm in 12 or 13 years. L. elliptica feeds sctively during summer when food is sufficiently provided, implying that food may be the most inportant fator regulating the growth. Seasonal variations in food availability, and metabolic process in starvation condition possibly during winter, however, are yet to be further investigated.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.33-40
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• 2008

Ultastructural studies of oocyte degeneration and follicle cells in female Spisula sachalinensis are described for clams collected from Jumunjin, Gangwondo, Korea. The follicle cells playan integral role in vitellogenesis and oocyte degeneration by assimilating products originating from the degenerated oocytes (thus allowed the transfer of yolk precursors needed for vitellogenesis). The functions of the follicle cells include phagocytosis and intracellular digestion of products originating from oocyte degeneration. During the period of oocyte degeneration, follicle cells of this species probably have lysosomal systems for the breakdown and reabsorption of various phagosomes(phagolysosomes) in the cytoplasm for nutrient storage; this process has been observed in other bivalves.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.33-43
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• 2004

A carbon budget model was constructed and analyzed for the Bangjukpo surf zone ecosystem in southern Korea by using the NETWRK. The model consists of 11 living and 1 non-living groups. Using boxes and arrows, a topological map was created to depict biomasses of each group and exchange rates between them. The system includes primary producers of phytoplankton and benthic algae, primary consumers of particle feeding zooplankton, carnivorous zooplankton, meiobenthos, malacostracans and bivalves, and top consumers of detrivorous, omnivorous, carnivorous and piscivorous fishes. The surf zone ecosystem was analyzed by means of network analysis, showing total system throughput of $574\;gCm^{-2}yr^{-1},$ development capacity of $1,876\;gCm^{-2}yr^{-1},$ ascendancy value of $768\;gCm^{-2}yr^{-1},$ Finn cycling index of $4.4\%$ and internal relative ascendancy of $27\%.$ These results were compared with similar data from other systems.

• The Korean Journal of Malacology
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• v.31 no.3
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• pp.253-255
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• 2015

The family Olividae includes predatory species with medium-sized, glossy, elongated oval-shaped shell. As sand-dwellers, they are broadly distributed in tropical and subtropical oceans. They feed mostly on other mollusks and carrions including sea snails and bivalves. To date, two species in the genus Amalda (subfamily Ancillinae) have been reported in Korean waters. In this study, Amalda rubiginosa (Swainson, 1823) was collected from Korean waters and morphologically described in details as a first record.

• The Korean Journal of Malacology
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• v.31 no.3
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• pp.221-232
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• 2015

Observations in beach, intertidal and upper subtidal environments in Peter the Great Bay (north-western East Sea) have shown that attached algae were found on empty shells of 13 species of epifaunal and infaunal bivalve mollusks. Thirteen algae species were identified on empty dislodged shells but more than 50 species are known to be epibiotic on living bivalves. The dislodgement of shells with attached algae takes place in semi-enclosed, low-energy areas, as well as those which are open and affected by strong wave action, indicating the large scale of this phenomenon. The significance of seaweed transportation of living mollusks and their empty shells in the coastal zone, involving both taphonomic and ecological processes, is stressed. Algae appear to be a taphonomic agent and play a similar role as compared to birds or hermit crabs, but they act passively and contribute to environmental mixing in death assemblages in coastal environments.