• 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.

• Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.321-324
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• 2015

The first zoeal characters of Sesarmops intermedius (De Haan, 1835) [=Sesarma (Sesarma) intermedium], belonging to the family Sesarmidae, are described and illustrated in detail based on laboratory-hatched material from a female collected from Gangjeung, Seogwipo, Jeju Island. Morphological comparison is performed based on previous descriptions of Sesarma (Sesarma) intermedium from Japan and three other species in the Sesarmidae. The first zoea of Sesarmops intermedius can be readily distinguished from those of the three species Chiromantes haematocheir [=Sesarma (Holometopus) haematocheir], Chiromantes dehaani [=Sesarma (Holometopus) dehaani], and Parasesarma pictum [=Sesarma (Parasesarma) pictum] by the presence of two setae on the exopod of the antenna, fine setae on the inner and outer margin of the forked spine of the telson, and three aesthetascs and one simple seta on the antennule.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.298-306
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• 2010

We estimated aboveground primary productivity of Salix nipponica based on biomass using allometry and basal area at Janghang wetland in Han River estuary. In addition, we estimated secondary production of sesarmine crab (Sesarma dehaani) living under the Salix community to interpret relationships between Salix nipponica and Sesarma dehaani. Salix nipponica showed primary productivity of 4,777 g DW $m^{-2}yr^{-1}$, which appear to be the highest primary productivity in South Korea. The estimated amount of autochthonous organic matter from S. nipponica and allochthonous organic matter from the Han River into sediment was 359 g C $m^{-2}yr^{-1}$ and 347 g C $m^{-2}yr^{-1}$, respectively. The secondary productivity of Sesarma dehaani was 100.2 g FW $m^{-2}yr^{-1}$, which was 2.1% of the primary productivity of S. nipponica. The biomass of Sesarma dehanni was average 140 g FW $m^{-2}$, which consumed their prey of approximately 2,140 g FW $yr^{-1}$, which is equivalent to approximately 208 g C $m^{-2}yr^{-1}$.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.31-42
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• 2019

Background: Han River estuary is a national wetland reserve near the Demilitarized Zone (DMZ) between South Korea and North Korea. This trans-boundary estuary area has been well preserved and shows distinctive plant communities along the salinity gradient. To elucidate energy flows and nutrient cycling in this area, we studied trophic relations between the dominant sesarmid crab, Sesarma dehaani, and food sources in three wetlands with different environments along the estuarine gradients. Results: Stable isotope signatures (${\delta}^{13}C$ and ${\delta}^{15}N$) of the crabs were significantly different among the sites and body size classes. Seasonal changes in ${\delta}^{13}C$ of small crabs were distinct from those of large individuals at all the sites. The isotopic values and fatty acid profiles of the crabs were more different among the sites in September than in May. In May, large-sized crabs utilized more plant materials compared to other dietary sources in contrast to small-sized crabs as revealed by a stable isotope mixing modeling, whereas contributions to diets of crabs were not dominated by a specific diet for different body size in September except at site 1. Based on PCA loadings, fatty acid content of $18:3{\omega}3$, known as a biomarker of plant materials, was the main factor to separate size groups of crabs in May and September. The ${\delta}^{13}C$ value of sediment had high correlation with those of small-sized crabs at site 1 and 2 when 1-month time lag was applied to the value for crabs during the surveyed period. Conclusions: Based on the stable isotope and fatty acid results, the consumption habits of S. dehaani appear to be distinguished by sites and their size. In particular, smaller size of S. dehaani appears to be more dependent on fewer food sources and is influenced more by the diet sources from the sediments in Han River estuary.

• Animal cells and systems
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• v.16 no.2
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• pp.162-171
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• 2012

We investigated food webs of a $Salix$ $subfragilis$-dominated wetland in the Janghang wetland in the Hangang estuary, which is very close to the Demilitarized Zone, along the west coast of Korea. Our study focused on understanding sesarmine crab ($Sesarma$ $dehaani$)-related food webs in a $S.$ $subfragilis$ forest. For our study, we used carbon and nitrogen stable isotopes and fatty acid biomarkers. We collected samples of plants, animals, and detrital sediment from four quadrats ($5{\times}5m^2$) set in the $S.$ $subfragilis$ community. Samples were collected from September 2006 to June 2009, except during the winter hibernation period of $S.$ $dehaani$. In the wet season, the sediment showed relatively high ${\delta}^{13}C$ and low ${\delta}^{15}N$ signatures compared with relatively low ${\delta}13C$ and high ${\delta}15N$ signatures in the dry season. Mature $S.$ $dehaani$ appeared to feed on fresh leaves and other carbon sources, such as immature individuals or fish, in addition to detrital sediment, which appeared to be the main carbon source for immature crabs. Principal component analysis of fatty acid biomarkers of $S.$ $dehaani$ showed a clear difference between immature individuals (10-30 mm) and mature ones (larger than 30 mm), indicating that the main food source for immature crabs was detrital sediment, whereas mature crabs foraged plants in addition to consuming detrital sediment. On the basis of our results from stable isotope and fatty acid analyses, mature $S.$ $dehaani$ appeared to feed on detrital sediment and fresh leaves of $S.$ $subfragilis$ in summer in addition to engaging in cannibalism of immature individuals.

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.197-202
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• 1989

This study was performed to observe the susceptibility of dogs and cats as definitive hosts of Paragonimus ilektsuenensis. The metacercariae of this luke were obtained from Sesarma dehaani collected at a focus near the mouth of Sumjin river in November, 1986 and February, 1987. The larvae isolated from the crabs were introduced Per os into 7 albino rats, 2 dogs and 3 cats. The adults were recovered from the experimental animals, End they were morphologically observed and measured. The results were as follows: 1. The recovery rate of adult worms at 42 days after infection was 53.3% from three albino rats, 21.0% from a dog and 12.7% from two cats. Most of the worms were recovered from the worm capsules in the lungs. 2. The size of worms recovered from albino rats, a dog, and cats 42 days after infection aver-aged $6.3{\times}3.2mm,{\;}6.3{\times}3.0mm,{\;}or{\;}6.2{\times}3.5mm$, respectively. There were little differences in the morphology of worms by different experimental animals. 3. The size of eggs from a dog was $88.9{\times}49.3{\mu\textrm{m}}$, and that from cats was $84.3{\times}53.7{\mu\textrm{m}}$ on average. Dogs and cats were good definitive hosts of p. iloktsuenensis. This fact suggests that human infection by this luke may be possible if the metacercariae were ingested.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.250-256
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• 2005

A benthic faunal survey of the Hangang Estuary located in the northwestern part of South Korea was performed in October 2004. A total of 11 species identified, which were comprised of two species of molluscs bivalves (Limnoperna fortunei and Corbicula felnouilliana) in two families, two species of annelids polychaetes (Neanthes japonica and Nephtys caeca) in two families, and seven species of decapods (Palaemon carinicauda, P. annandalei, P. modestus, Ilyoplax deschampsi, Eriocheir sinensis, Eriocheir leptognathus and Sesarma dehaani) in four families. Four of the 11 species in six families, Limnoperna fortunei, Neanthes japonica, Nephtys caeca and Palaemon modestus, were newly found in this study area. Eleven species were presently listed with brief ecological remarks.

• Parasites, Hosts and Diseases
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• v.27 no.1
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• pp.57-66
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• 1989

A scanning electron microscopic study was performed to observe the tegumental ultrastructures of Paragonimus iloktuenensis according to its developmental stages. The metacercariae were obtained from the liver of the brackish water crab, Sesarma dehaani. Juvenile and adult p. iloktsuenensis were recovered from the experimental rats on 2, 4 and 8 weeks after infection. The findings were summarized as follows: 1. The encysted metacercariae were charaeteristically gourd-shape, with their whole body surface beset with numerous spade-shape spines. The Barge, type II sensory papillae (non-ciliated round swellings) were arranged along the rim of the oral and ventral suckers, 11~12 and 6~8 in numbers respectively, 2. Two-week old juvenile worms, recovered chieay from the liver of the experimental rats, were slender in body shape: with their ventral sucker near the anterior one-third level. The distribution of tegumental spines was less dense than in the encysted metacercariae. The spines were with 1~2 pointed tips and 3~.4 longitudinal splits. Numerous ciliated knob-like, type I papillae were observed in both sides of the oral sucker, and 6 large, type If papillae were arranged along the rim of the ventral sucker. 3. Four week old worms, recovered from the thoracic cavity and/or lung parenchyme of the experimental rats, were thicker than wide in body configuration, and their ventral sucker was located near the anterior one.fourth level. The tegumental spines at ventral surface were grouped, each group with 3~5 aggregated ones. The type I and type II papillae (small-sired) were distributed chiefly around the rim of two suckers. 4. Adult (eight-week old) worms, recovered from the capsules in the lung parenchyme, were very stout, and covered densely with bearfoot like spines. At dorsal surface, cobblestone-like cytoplasmic processes were well-developed, with many tegumental spines embedded in them. It was observed in this study that the tegument of p. iloktsuenensis continued to change and differentiate as the worms grew to be adults.

• Parasites, Hosts and Diseases
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• v.27 no.2
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• pp.119-130
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• 1989

An experimental pathological study was performed to observe the effect of prasiquantel treat- ment on the pulmonary lesions of the rat lung cuke, Paragonimus ilektsuenensis. The metacercariae were obtained from the freshwater crab, Sesarma dehaani, and 40 rats (wistar) were fed each with 10 metacercariae. On 20 rats prasiquantel treatment ($100mg/kg/day{\times}5$ days) was done at 5 weeks after the infection while remaining 20 rats were kept untreated for use as controls. The drug.treated rats and the untreated ones were sacrificed 3, 7, 14, 21 or 28 days later for the observation of lung pathology. The rats infected with P. iloktsuenensis showed remarkable pulmonary changes; gross features of hemorrhagic and nodular worm capsules protruded on to the surface of the lung, and histologically local atelectasis, inflammatory cell infiltration, and egg granuloma around the worm capsules each containing one or two worms. Praziquantel treatment of the rats was shorn to be highly effective in killing the worms and to lead them to degenerate, as early as in 3 days post-treatment. Almost all worms in the lung were dead and absorbed by the host cells in 21 days post-treatment, except a few living ones seen in a rat of 14-day post-treatment group. In most of the rats treated the pulmonary lesions showed the signs of resolution; regression of worm capsules with mummification of worms, decrease of inflammatory cell infiltration, improvement in the degree of atelectasis, and decreases in the frequency and size of the egg granuloma. From the results it is concluded that prasiquantel is highly effective for the treatment of rat P. iloktsuenensis infection in the lung, not only by its direct killing effect of the worms but also due to the excellent resolution capacity of the pulmonary tissues.