• 한국수산과학회지
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• 제47권5호
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• pp.501-507
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• 2014

Norovirus (NoV) is a major cause of food poisoning outbreaks in Korea. Most NoV outbreaks originate from environmental contamination, but bivalves such as oysters are also important vectors. Oyster Crassostrea gigas contamination by NoV has been reported in Korea, but no quantitative analyses of NoV have been performed. We investigated the NoV concentration in 21 oyster samples from a Korean commercial oyster-growing area with confirmed fecal contamination from January to December 2012, using real-time reverse transcription-polymerase chain reaction. Additionally, we assessed the NoV concentration after heating to investigate the effects of heat treatment on NoV-infected oysters. In NoV-positive samples, the cycle threshold (Ct) values were 37.43-39.41 and 36.77-39.30, while viral concentrations were $8.97{\times}10^2-2.24{\times}10^2$ and $3.05{\times}10^2-7.47{\times}10^1$ copies/g for genogroups I and II, respectively. After heat treatment, NoV genogroup I decreased by 83.4%, 88.0%, 89.4% and 100% at $60^{\circ}C$, $68^{\circ}C$, $70^{\circ}C$, and $100^{\circ}C$, respectively, for 15 min, while genogroup II respectively decreased by 67.3%, 76.3%, 80.1%, and 89.8% under the same conditions.

• Environmental Analysis Health and Toxicology
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• 제21권2호
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• pp.115-126
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• 2006

This study was conducted to find out survival rate, activity, growth and change of the organ structure of bivalves exposed to heavy metal. The results of the study confirmed that zinc (Zn) induces reduction of survival rate and activity, abnormality of organ structure of the equilateral venus, Gomphina veneriformis. Experimental groups were composed of one control condition and three Zn exposure conditions ($0.64mg\;Zn{\iota}^{1},\;1.07mg\;Zn{\iota}^{-1},\;1.79mg\;Zn{\iota}^{-1}$). As the concentration of zinc increased the accumulation of lipofucin increased in the digestive gland. Survival rate was the lowest in the lowest Zn exposure group at $0.64mg;Zn{\iota}^{-1}$. Growth was not significantly different between the control and exposure group. Activity. with the exception of the lowest Zn exposure group at $0.64mg\;Zn{\iota}^{-1}$, was similar between the control and exposure group. Histological analysis of organ system illustrated expansion of hemolymph sinus, loss of striated border of inner epidermis, increase in the number of mucous cell in the mantle. Also, histological degenerations as epithelial necrosis and hyperplasia of mucous cells are recognized in the gill and foot.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.183-190
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• 2002

To determine the effect of body size on the clearance rate and ingestion rate of small intertidal bivalves, Glauconome chinensis, feeding experiments were conducted on individuals of 12 different size classes, from 4 to 16 mm in shell length. Relationships between morphological parameters were also determined. The clearance and ingestion rates of G. chinensis responded similarly to their body size, ranging from 1.3 to 28.2 mL/hr/ind. and from 24.0 to 458.5, ${\mu}gC/hr/ind$., respectively. Both rates increased significantly (p<0.001) as shell length increased from 4 to 9 mm, although neither rate changed significantly when shell length was in the range from 12 to 16 mm. The weight-specific clearance rate $(CR_w)$ and ingestion rate $(IR_w)$ decreased with increasing body size, with values from 1.0 to 3.1 L/hr/g and from 17.9 to 51.3 mgC/hr/g, respectively. The $CR_w$ of G. chinensis was intermediate compared to those of larger bivalve species. The clearance rate (CR) relative to flesh dry weight (FDW) of G. chinensis were fitted well to the power function: $CR=0.43\times(FDW)^{0.71}\;(r^2=0.89)$. The exponent of fitting equation (0.71) of G. chinensis was higher than those of Mytilus edulis (Walne, 1972), Crassostrea gigas (Walne, 1972), and Placopecten magellanicus (MacDonald and Thompson, 1986).

• 한국패류학회지
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• 제18권1호
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• pp.1-8
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• 2002

경남 고성만과 강진만에서 서식하는 굴과 피조개에 대한 체성분의 계절적 변화를 Station별로 조사 분석하였다. 굴의 경우 대체로 조사정점에서 모두 여름에 단백질의 함량이 높았으며, 겨울 동안 지질과 탄수화물의 함량이 높아 정점 간에는 뚜렷한 차이는 없었으나, Station 2에서 다소 양호한 상태를 나타내었다. 글리코겐의 함량은 여름에 현저히 감소하였으며, 에너지 함량은 11월부터 이듬해 3월까지 높은 값을 나타내었다. 한편 피조개의 경우 단백질은 여름 동안 낮았으나 탄수화물은 높게 나타났다. 지질은 2-5월 동안 높았으며, 글리코겐의 함량은 6-9월 동안 낮았고, 에너지 함량은 겨울 동안 낮게 나타나 어장간의 뚜렷한 차이는 없었다.

• 한국패류학회지
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• 제27권3호
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• pp.253-259
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• 2011

Boring behaviour and drilling mechanism were investigated by visual observations. In this study, of two kinds of holes (the outer and inner holes) which are formed by drilling of boring gastropod Lunatia fortunei (Naticidae), the diameters of the outer holes are broader and larger than those of the inner holes, and their holes look like the crater in shape, as seen in all valves of bivalves bored by Naticidae species. Two kinds of glands (the accessory boring gland and accessory salivary gland) on the foots of boring gastropods have been investigated. Of them, it has been confirmed that only the accessory salivary glands on the foots secreted sulphuric (acidic) components in the mucus (secretion), while the accessory boring glands on the foots did not secrete their components. In this study, we confirmed that L. fortunei possess the accessory boring gland on the foot, as seen in most species in Naticidae. Accoeding to the results of the experiment of the blue litmus paper tests of the mucus (secretions) secreted from the accessory boring gland the color of the blue litmus paper did not turn red in color because chemical components of mucus (secretion) secreted from the accessory boring gland on the foot of L. fortunei (boring gastropod) were not acidic components. It is supposed that the mucus, which is secreted from the accessory boring gland, contained gelatin-like substances or enzymes without acidic components, as already reported in Naticidae species. Therefore, these substances may be involved in softening the surface of the valves of M. veneriformis. Consequently, it is assumed thar L. fortunei bores holes through the shells of molluscs by means of following 3 methods: (1) a softening of the calcareous shells of M. veneriformis with chemical secretions (including gellatin-like substances or enzyme except for acidic components) from the accessory boring glands, (2) mechanical rasping with the radula, (3) a combination of both. In this study, particularly, acidic components, which are involved in softening the surface of the shells, are not associated with the boring mechanism of L. fortunei because chemical acidic components were not detected in the mucus (secretion), as found in Naticidae species.

• 한국패류학회지
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• 제28권3호
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• pp.277-291
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• 2012

Aquaculture is challenged by a number of constraints with future efforts towards sustainable production. Global climate change has a potential damage to the sustainability by changing environmental surroundings unfavorably. The damaging parameters identified are water temperature, sea level, surface physical energy, precipitation, solar radiation, ocean acidification, and so on. Of them, temperature, mostly temperature elevation, occupies significant concern among marine ecologists and aquaculturists. Ocean acidification particularly draws shellfish aquaculturists' attention as it alters the marine chemistry, shifting the equilibrium towards more dissolved CO2 and hydrogen ions ($H^+$) and thus influencing signaling pathways on shell formation, immune system, and other biological processes. Temperature elevation by climate change is of double-sidedness: it can be an opportunistic parameter besides being a generally known damaging parameter in aquaculture. It can provide better environments for faster and longer growth for aquaculture species. It is also somehow advantageous for alleviation of aquaculture expansion pressure in a given location by opening a gate for new species and aquaculture zone expansion northward in the northern hemisphere, otherwise unavailable due to temperature limit. But in the science of climate change, the ways of influence on aquaculture are complex and ambiguous, and hence are still hard to identify and quantify. At the same time considerable parts of our knowledge on climate change effects on aquaculture are from the estimates from data of fisheries and agriculture. The consequences may be different from what they really are, particularly in the temperature region. In reality, bivalves and tunicates hung or caged in the longline system are often exposed to temperatures higher than those they encounter in nature, locally driving the farmed shellfish into an upper tolerable temperature extreme. We review recent climate change and following environment changes which can be factors or potential factors affecting shellfish aquaculture production in the temperate region.

• 한국수산과학회지
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• 제1권2호
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• pp.115-119
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• 1968

1. 미개척상태인 간석지를 패류양식장으로 개척하기 위하여 4종의 패류 고밀도 양식지에 있어서 저질의 토성, 보수능, 수소이온농도, 치환성 칼슘, 그리고 유기물 함양에 관한 기초조사를 실시하였다. 2. 비쭉이, 동죽, 가무락, 그리고 바지락의 각 고밀도 서식지간에서는 토성에 차이가 있었다. 3. 보수능, 수소이온농도, 치환성 칼슘의 함양은 4종 패류의 각 고밀도 서식지간에 유의차가 없었다. 4. 유기물의 함량은 비쭉이와 가무락 서식지간을 제외한 다른 모든 서식지간에서 매우 유의한 차를 볼 수 있었다. 5. 본 조사 결과로서는 아직 판단키 어려우나 패류양식장의 적지선택에 간석지 토양의 토성과 유기물의 함량이 중요한 요인으로 생각된다.

• Fisheries and Aquatic Sciences
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• 제12권4호
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• pp.276-285
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• 2009

Despite great commercial interest, relatively little has been described about molecular mechanism of bivalve reproduction. We investigated genes involved in ovarian maturation of the Yesso scallop, Patinopecten yessoensis. GSI index and histological analysis revealed that maturation of ovary begin in February and spawning period is from April to June which is similar to the previous study in the East Sea. As result of combination analysis of differential display RTPCR (DDRT-PCR) and histological examination, vitellogenin (Vg), ferritin (Ft) and ADT/ATP carrier protein (ACC) were identified as differently expressed genes in maturating ovary. Endpoint RT-PCR results showed that Vg is ovary-specific genes whereas Ft and ACC are expressed ubiquitously suggesting that Vg can be good molecular markers for ovarian development and sex determination in bivalves. Quantitative PCR results revealed that Vg were expressed highest during growth stage and appears to play a major role in oocyte maturation. On the contrary, expression of Ft was highest after spawning stage, which suggests that up-regulation may be involved in spawning and inactive stages in which the scallops recover from spawning. In addition, high level of the mitochondrial gene, ACC, may play a role in energy metabolism in maturating oocytes. Isolation and molecular studies of these key genes will expand our knowledge of the physiological changes from various exogenous factors including temperature, salinity, pH, even or numerous endocrine disrupting chemicals (EDCs) during reproductive cycle. In addition, further study of these genes implicates various industrial applications including the stable seed production, increased food quality, or economic aquaculture system.

• 한국어류학회지
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• 제24권1호
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• pp.35-40
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• 2012

부산 연안해역에서 2004년 1월부터 12월까지 매월 1회 채집된 황돔($Dentex$ $tumifrons$) 317개체의 식성을 조사하였다. 황돔의 표준체장(SL)은 10.2~27.8 cm 범위였다. 황돔의 위내용물을 분석한 결과 새우류(Macrura)를 주로 섭식하는 육식성어종(carnivore)이었다. 새우류 다음으로 어류(Pisces)가 중요한 먹이생물이었다. 그 다음으로 집게류(Anomura), 단각류(Amphipoda), 게류(Brachyura), 극피동물(Echinodermata), 두족류(Cephalopoda) 순으로 섭식하였다. 그 외, 갯지렁이류(Polychaeta), 갯가재류(Stomatopoda), 이매패류(Bivalivia), 패충류 (Ostracoda), 곤쟁이류 (Mysidacea) 등을 섭식하였지만 그 양은 매우 적었다. 가장 작은 크기군인 10~13 cm의 크기군에서는 새우류가 가장 중요한 먹이생물로 나타났다. 13~16 cm 크기군에서는 새우류의 비율이 감소한 반면, 집게류, 극피동물, 게류의 비율이 증가하였다. 체장이 증가함에 따라 새우류, 집게류, 극피동물, 게류의 비율이 감소한 반면, 어류의 비율은 계속 증가하였다. 어류는 체장 25 cm 이상의 크기군에서는 위내용물의 대부분을 차지하였다.

• 한국어류학회지
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• 제22권1호
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• pp.41-48
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• 2010

통영 주변해역에서 출현하는 별망둑 (Chaenogobius gulosus)의 식성을 연구하기 위하여 2008년 10월에서 2009년 9월까지 채집된 333개체의 별망둑의 위내용물을 분석하였다. 별망둑의 체장범위는 표준체장 (SL) 2.0 ~ 12.6cm 이다. 별망둑의 위내용물을 분석한 결과 별망둑은 잡식성 어류로 구멍갈파래 (Ulva pertusa) 같은 해조류 (Seaweed)와 게류 (Brachyura)와 복족류 (Gastropoda)를 주로 섭식하였다. 그 외 이매패류 (Bivalvia), 갯지렁이류 (Polychaeta), 곤충류 (Hexapoda), 새우류 (Macrura), 곤쟁이류 (Mysideacea), 단각류 (Amphipoda) 등도 섭식하였지만 그 양은 많지 않았다. 체장 6cm 미만의 작은 개체는 복족류를 많이 섭식하였다. 그러나 체장이 증가함에 따라 복족류의 비율은 감소하였고, 해조류의 섭식이 증가하였다. 별망둑 위내용물은 계절에 따라 유의한 차이를 보였는데, 해조류는 다른 계절에 비하여 봄과 여름에 더 많이 섭식되었다.