• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.351-361
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• 2019

To investigate the temporal distribution of planktonic larvae of Tegillarca granosa and Anadara kagoshimensis in the Boseong coastal waters of South Korea, samples of planktonic bivalve larvae were taken from the coastal waters from June to September 2018 (this consisted of monthly sampling in June, July, and September with three- or four-day interval sampling in August). The samples were analyzed using metagenomic next-generation sequencing methods (target gene: mitochondria cytochrome c oxidase 1 region). In this study, a total of 21 bivalve operational taxonomic units (OTUs) were detected with the most abundant bivalve OTUs (relative mean abundance >1%) belonging to Magallana sikamea, Xenostrobus atratus, Musculista senhousia, Magallana gigas, Sinonovacula constricta, Anadara kagoshimensis, Kurtiella aff. bidentata, and Tegillarca granosa. In particular, Tegillarca granosa and Anadara kagoshimensis (the main fishery resources on the Boseong coast) accounted for 0.51-12.50% (average 4.00%) and 0.01-12.50% (1.92%), respectively. The planktonic bivalve larvae were most abundant from July to August. Anadara kagoshimensis was most abundant in early August but rare in the other investigated periods, whereas Tegillarca granosa was more abundant in late August. Bivalve larvae monitoring is important to predict the production of bivalve fisheries. Therefore, intensive monitoring is needed to understand the changes in planktonic bivalve larvae because potentially rapid turnover can respond to the ecological interaction of spawning bivalves.

• Journal of Aquaculture
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• v.19 no.4
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• pp.288-298
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• 2006

Larval distribution of bivalve from 29 stations in Deukryang Bay was examined from May to November in 1995. The abundance of total larvae increased from May ($3,736\;inds/m^3$) and reached maximum in August ($174,616\;inds/m^3$). But it decreased continuously until November ($2,171\;inds/m^3$). D-shape, early umbone and advanced umbone stage larvae composed of 76%, 18% and 6%, respectively, of total bivalve larvae. Nine larval species of bivalve were identified in this study. The mean abundance of Scapharca subcrenata larvae was $14,030\;inds/m^3$, which was 33.5% of total identified larvae. S. broughtonii (16.2%), Crassostrea gigas (12.5%), Mytilus edulis (10.2%) were also major species in order of their abundance. Considering the monthly larval occurrence in Deukryang Bay, main spawning month of bivalves except M. edulis and M. senhausia was estimated as July. Even though the spatial distribution of bivalve larvae in Deukryang Bay was different by the species, the larvae were generally abundant in the inner and west area of the bay, where was shallower and higher water temperature than the entrance and east area of the bay.

• 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.

• Ocean and Polar Research
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• v.32 no.3
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• pp.247-254
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• 2010

Single cell PCR analysis and light and scanning electron microscopic techniques were utilized to identify free living bivalve larvae in the coastal waters of Tae-an, on the west coast of Korea. Through DNA sequencing, venerid clam larvae were isolated and identified as Ruditapes philippinarum (99% similarity) and Meretrix lusoria (99%). Under microscopic observation, the D-veliger stage of R. philippinarum exhibited symmetrical shoulder angles and an elliptical ventral form. In contrast, M. lusoria displayed asymmetrical shoulder angles and a round ventral form in the umbonal stage. Size of the R. philippinarum larvae was $156{\pm}22{\mu}m$ in length, $126{\pm}12{\mu}m$ in height, $92{\pm}14{\mu}m$ in width with a length: height ratio of 1.23. Meretrix lusoria was $202{\pm}44{\mu}m$ in length, $161{\pm}35{\mu}m$ in height, $96{\pm}38{\mu}m$ in width with a length: height ratio of 1.25. Experimental results indicate that morphological and molecular characteristics provide evidence for the larval identification of these two venerid clam larvae species in nature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.368-376
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• 2015

The Feeding habits of larval Liparis tanakae collected from the Nakdong River estuary were studied. L. tanakae [3.8-10.6 mm notochord length(NL)] was a carnivore thatconsumed mainly copepods. Its diet also included small numbers of free-living flatworms (Macrostomida), tintinnids, cladocerans, and polychaetes larvae. To evaluate ontogenetic changes in dietary composition, three size groups were designated: 3-5, 5-7, and >7 mm. Copepods were the most important prey items for all size groups. The smallest size group frequently preyed on polychaete and bivalve larvae, along with copepods. As notochord length increased, the numbers of cladocerans and Macrostomida increased relative to those of polychaete and bivalve larvae.

• The Korean Journal of Zoology
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• v.4 no.1
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• pp.13-20
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• 1961

우리나라 서해안인 경기도 부천군 선재도에서 산출되는 이매구류의 출현 빈도 분포 상태를 1959년 8월부터 1960년 10월에 걸쳐서 생태학적인 조사를 하였다. 1) Sampling 은 motor pump를 사용하여 원하는 깊이에 따라 각각 plankton을 채집하여 현미경으로 고나찰하여 KArvae 의 수를 조사하였다. 2) 각 stage의 larvae을 측정한 결과, 가장 어린 것은 60$\times$54$\mu$이었고, 가장 큰 것 은 320$\mu$336$\mu$이었다. 3) 이매구의 larvae 들은 수중에서 불규칙하게 분포하였다. 온도의 상승에 따라서 larvae의 분포는 증가되고, 대체로 온도가 하강함에따라서는 감소되었다. 4) 어린 stage의 larvae 수는 7월-9월 에 걸쳐 출현빈도가 높았다. 이것은 이시기가 선재도에 있어서는 이매구류의 산란시기라고 생각된다. 5) 8월-9월에 걸쳐서 대형의 alrvae의 출현빈도가 감소되는데, 이것은 larvae가 착생되었기 때문이라 생각된다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.373-374
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• 2003

There were many studies on the effects of red tide dinoflagellates on shellfish populations (Nielsen and Stromgren, 1991; Lesser and Shumway, 1993; Luckenbach et al., 1993; Matsuyama et al., 1997; Li et al., 2001). However, these studies mainly focused on the toxic effects of dinoflagellates oui adults or juveniles. Interactions between dinoflagellates and bivalve larvae have not been understood comprehensively yet. (omitted)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.457-467
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• 1990

Sessile barnacle, Balanus trigonus Darwin, was collected from the intertidal rocks and the external shells of bivalve Mylius coruscus. The nauplius and cyprid larvae were cultured in a constant temperature cabinet at a temperature of $20^{\circ}C$ and a light regime of 14 h light and 10 h darkness. Larval development includes the six nauplius stages and a cyprid stage prior to settlement and metamorphosis to the young adult. Morphological characteristics including antennules, antennae and mandibles are described and illustrated. All nauplius larvae have trilobed labra typical in balanoides. The developmental time taken from newly hatched nauplius I to cyprid was $9\~13$ days and averaged 11 days.

• The Korean Journal of Malacology
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• v.27 no.2
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• pp.91-97
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• 2011

This study examines the morphological features of larval and postlarval shells of the paedomorphic bivalve Crenella decussata Montagu, 1808 from the Sea of Japan. During the early morphogenesis of the shell of C. decussata the following characteristics appear: prodissoconch I -the anterior and posterior provincular teeth, a broad primary ligament pit located on the chondrophore; nepioconch - the anterior and posterior juvenile teeth,primary lateral teeth, fine commarginal and radial sculpture. Larvae of C. decussata distinctly differ from other mytilid larvae by a D-shaped shell, absence of umbo, astraight hinge margin, and homogeneous fine-grained sculpture without co-marginal lines of growth. These shell characters indicate lecithotrophic development of this species. Some morphostructures are revealed which might be used in crenellin taxonomy.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.33-38
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• 2015

The diet composition of Leiognathus nuchalis were studied using 350 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. L. nuchalis was carnivorous feeder that consumed mainly copepods, crab larvae, and shrimp larvae. Its diet also included small quantities of polychaetes, amphipods, euphausiids, bivalve larvae, and gastropod larvae. The size of L. nuchalis ranged from 3.0 to 9.8 cm in body length (BL). L. nuchalis underwent an ontogenetic dietary shift. 3~5 cm size individuals fed mainly on copepods. 5~7 cm size individuals fed mainly crab larvae and shrimp larvae. 8~10 cm size individuals fed mainly polychaetes. The size increases, the weight of food organisms are constantly increased.