• Journal of the korean society of oceanography
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• v.37 no.4
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• pp.232-241
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• 2002

The potential role of environmental factors on extractable lipofuscin accumulation rate in the blue crab was studied by examining the effect of temperature on laboratory reared blue crabs and the effect of trace metals from samples collected at impacted sites (Baltimore Harbor) and a relatively pristine site (outdoor ponds at Horn Point Laboratory, Cambridge, MD, USA). Lipofuscin levels did not significantly related with sampling sites or heavy metal concentrations in the crab tissue. Heavy metal body burden was highly variable among sampling sites and tissue types but significantly higher for both impacted areas (Curtis Creek and Inner Harbor) in comparison to the reference site. Among tissue types, gills showed the highest metal concentrations with the exception of Hg, which was highest in muscle tissue. For two groups of crabs that were held at either ambient (4 to 1$0^{\circ}C$) or heated seawater (19$^{\circ}C$) for two months, normalized-lipofuscin levels were significantly different (P-0.001). Results suggest that temperature may affect lipofuscin accumulation (=0.25ng-lipofuscin/mg-protein/temperature-degree day). Therefore, temperature should be considered for accurate age calibration of crab populations using lipofuscin.

• Animal Systematics, Evolution and Diversity
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• v.28 no.2
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• pp.117-125
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• 2012

Many members of xanthid crabs have the black coloured fingers and are found easily in the intertidal or subtidal zone. Three xanthids, $Danielea$ $noelensis$ (Ward, 1934), $Etisus$ $anaglyptus$ H. Milne Edwards, 1834, and $Gaillardiellus$ $rueppelli$ (Krauss, 1843), are newly reported from Korean waters as a result of continuous taxonomic studies on crabs. Of these, the present specimen of $D.$ $noelensis$ has rather projecting angle on the antero-external border of the merus of the third maxilliped differed from that of the original description. The genus $Danielea$ Ng and Clark, 2003 and the genus $Etisus$ H. Milne Edwards, 1834 are also reported first time from Korean fauna. Their descriptions are provided with illustrations. Korean Xanthoidea now consists of 28 species belonging to 24 genera.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.369-379
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• 1993

Using a successive removal approach the mechanism of sampling capture efficiency of blue crabs by dredges was studied in Chesapeake Bay during winter 1992. For the twenty-six field experiments no significant statistical differences were detected in dredge efficiency using general linear model analysis by factors including bottom sediments, water depths, and sampling vessels. Dredge efficiency (i.e., catchability) was estimated by two methods, Leslie (Leslie and Davis, 1939) and a simple revised method. Mean catchability was estimated at 0.26 (SE=0.03), indicating that only $26\%$($95\%\;C. I.=20{\sim}32\%$) of crabs present in the path of the dredge of a given sampling area are caught with a single dredge tow. Dredge efficiency declined exponentially as crab density increased.

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.168-175
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• 1998

Feeding habits of juvenile Acanthopagrus schlegeli collected from the eelgrass bed in Kwangyang Bay were studied. A. schlegeli (1~7cm SL) was a carnivore which consumed mainly amphipods (gammarid and caprellid amphipods), crabs and shrimps. Its diets included small quantities of gastropods, polychaetes, hydroids, tanaids, copepods and isopods. A. schlegeli showed ontogenetic changes in feeding habits. Small individuals preyed mainly on gammarid amphipods, gastropods and polychaetes. However, crabs and shrimps were heavily selected with increasing fish size.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.806-812
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• 1998

Feeding habits of juvenile Takifug niphobles collected from the eelgrass bed in Kwangyang Bay were studied. T. niphobles (2$\~$8 cm SL) was a carnivore which consumed mainly amphipods (gammarid and caprellid amphipods), crabs, shrimps and gastropods. Its diets included minor quantities of polychaetes, copepods, tanaids and isopods. T. niphobles showed ontogenetic changes in feeding habits. Small individuals preyed mainly on gammarid amphipods, caprellid amphipods and gastropods. However, crabs and shrimps were heavily selected with increasing fish size.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.225-227
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• 1989

This study was performed to observe the recent infection status of Sesarma dehaani with the metacercariae of p. itoktsuenensis in the well-known cnzootic focus, Sumjin river delta. A total of 74 Sesarma dehaani were collected from a focus near the mouth of the Sumjin river in November, 1986 and February, 1987. The crabs were examined for P. iloktsuenensis metacercariae by the method of Seo and Kwak(1972). The metacercariae of p. iloktsuenensis were found in the liver of the crabs. Among the 74 crabs examined, 47(63.5%) were found infected with 1∼102 metacercariae(18.2 per crab). The infection rate and metacercarial density increased as the sixte of the crab was increased. From the results, it is suggested that the life cycle of p. ilokssuenensis is actively maintained in the Sumjin river basin.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.265-271
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• 2015

The feeding habits of Okamejei kenojei were studied using 242 specimens collected from October 2010 to September 2011 in the coastal waters of Gadeok-do, Korea. O. kenojei was carnivorous feeder that consumed mainly shrimps, crabs, and fishes. Its diet also included small quantities of stomatods, cephalopods, amphipods. The size of O. kenojei ranged from 10.4 to 47.4 cm in total length (TL). O. kenojei showed ontogenetic dietary shift. <15.0, 15.0-19.9 cm size classes fed mainly on shrimps and amphipods. 20.0-24.9 cm size class fed mainly shrimps and crabs. Thereafter, shrimps and crabs were decreased with ontogenesis while fishes and cephalopods were increased. Increasing size, the mN/ST were constantly decreased, but mW/ST were constantly increased.

• Korean Journal of Ichthyology
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• v.18 no.3
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• pp.216-222
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• 2006

Feeding habits of Pagrus major collected in the coastal waters off Busan from January to December 2004 were studied. P. major ranged form 8.5 to 44.6 cm in standard length. P. major was a carnivore which consumed mainly hermit crabs, amphipods, crabs, shrimps, polychaetes, echinoderms, and fishes. Its diets included small quantities of gastropods, bivalves, stomatopods, cephalopods, cnidarians, and isopods. It showed ontogenetic changes in feeding habits. Small individuals (8~15 cm SL) preyed mainly on shrimps. However, individuals from 15 cm to 25 cm SL preyed mainly on hermit crabs and polychaetes. Individuals over 25 cm SL preyed mainly on fishes and echinoderms.

• The Korean Journal of Ecology
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• v.28 no.3
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• pp.141-147
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• 2005

To clarify seed distribution in sediment and its burial properties of Suaeda japonica, the vertical and horizontal distribution of seeds, organic content of sediment, and sediment content delivered by crabs were studied in mud tidal-flat of Walgot-dong, Siheung, Gyeonggi Province, from March 1999 to October 2000. The 94% and 6% of S. japonica seeds were buried under and outside the maternal plant crown, respectively. Organic matter contents of sediment were higher at the area (17%) covered than at the one (8%) uncovered by S. japonica. In the area covered by S. suaeda, organic matter profiles of sediment showed vertical variation from 19% in surface (1 cm depth) to 14% in 6 cm depth. S. japonica seeds buried in sediment decreased from 45% in 2 mm depth to 0% in 12 mm depth. The density of crabs was higher in the vegetated area than in the non-vegetated one. Especially, the density of Cleistostoma was about 8 times higher in the former than in the latter In the vegetated area, the amount of sediment delivered by crabs was estimated to be 2,409 $cm^3{\cdot}m^{-2}$, and this could ascend the height of sediment to 2.4 mm. Consequently, it might be interpreted that plant debris (organic matters) of maternal plants and sediment delivered by crabs made the S. japonica seeds bury well. By relationship between crab distribution and vegetation, it was thought that crabs got a benefit from S. japonica.

• Journal of fish pathology
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• v.17 no.3
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• pp.213-216
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• 2004

To confirm the possibility of a wild marine crab, Gaetice depressus, as a carrier for white spot syndrome virus (WSSV) and to develop an alternative experimental model for WSSV in winter season, the susceptibility of the crab to WSSV was assessed by artificial challenge and subsequently tested for infection by PCR assay. The results revealed that the crabs were as highly susceptible as penaeid shrimps. WSSV caused 100% mortality in G. depressus within 16 days after intramuscular injection. The presence of WSSV in the moribund crabs was confirmed by PCR and was found in gills and muscle tissue. These results suggest that G. depressus can be naturally infected by WSSV via moribund shrimps, and can act as a potential carrier of WSSV. In addition, G. depressus can be used as an alternative experimental animal for WSSV.