• Journal of Species Research
• /
• v.1 no.1
• /
• pp.100-103
• /
• 2012

Nutria Myocastor coypus is one of a well known invasive riparian mammal found species around world from North America to Eurasia and Africa. In South Korea, feral nutrias inhabit areas from the Nakdonggang and Namgang (River) to their tributaries and Upo Wetland where they have had devastating effects on environment. Nevertheless, there has been little research about nutrias in Korea. This study is to analyze the genetic structure of the nutria population in the Upo Wetland and identify the origin of the source populations. Twenty individuals from the Upo Wetland were genotyped using 25 microsatellite loci. When compared with another introduced population, that of the Blackwater Nation Wildlife Refuge in U.S., the Upo population contains considerable genetic variations. Tests for Hardy-Weinberg equilibrium and Bayesian clustering analysis suggest the Upo population is genetically structured and has at least two source populations. This preliminary study presents the need for further in-depth studies about this species which should combine genetic and ecological studies.

• Parasites, Hosts and Diseases
• /
• v.56 no.4
• /
• pp.375-378
• /
• 2018

A total of 44 adult or juvenile nutrias were necropsied for disease survey. A large nodule was found in the liver of a nutria. The histopathological specimen of the hepatic nodule was microscopically examined, and sectional worms were found in the bile duct. The worms showed a tegument with spines, highly branches of vitelline glands and intestine. Finally, we histopathologically confirmed fascioliasis in a wild nutria. In the present study, a case of fascioliasis in a wild nutria is first confirmed in Korea.

• Korean Journal of Veterinary Service
• /
• v.40 no.2
• /
• pp.139-142
• /
• 2017

A six-year-old male captive nutria (Myocastor coypus) maintained in a closed space with a small vent was found dead in his cage. Gross findings showed multifocal nodules in varying sizes, small 0.5 to large 5 cm in diameter, intermixed with normal parenchyma were scattered all over the surface of the lungs and a kidney, which the cut surface was smooth, compact and whitish in color. Microscopically, small round to oval neoplastic cells with modest to slight amounts of cytoplasm formed acinar and gland-like structures. Immunohistochemically, cells were strongly positive for E-cadherin and slightly reactive for thyroid transcription factor-1 (TTF-1). Based on those diagnostic features, the neoplasia was diagnosed as primary pulmonary adenocarcinoma (small cell type) and metastasized into the kidney. This is the first case report of malignant pulmonary tumor and its metastasis in the nutria.

• Parasites, Hosts and Diseases
• /
• v.52 no.5
• /
• pp.531-535
• /
• 2014

Surveys on helminthic fauna of the nutria, Myocastor coypus, have seldom been performed in the Republic of Korea. In the present study, we describe Strongyloides myopotami (Secernentea: Strongyloididae) recovered from the small intestine of feral nutrias. Total 10 adult nutrias were captured in a wetland area in Gimhae-si (City), Gyeongsangnam-do (Province) in April 2013. They were transported to our laboratory, euthanized with ether, and necropsied. About 1,300 nematode specimens were recovered from 10 nutrias, and some of them were morphologically observed by light and scanning electron microscopies. They were 3.7-4.7 ($4.0{\pm}0.36$) mm in length, 0.03-0.04 (0.033) mm in width. The worm dimension and other morphological characters, including prominent lips of the vulva, blunted conical tail, straight type of the ovary, and 8-chambered stoma, were all consistent with S. myopotami. This nematode fauna is reported for the first time in Korea.

• Journal of Environmental Impact Assessment
• /
• v.22 no.3
• /
• pp.241-254
• /
• 2013

The nutria(Myocastor coypus) that is originated from South America is a representative Invasive alien species in Korea. invasive alien species is one of the biggest causes for the loss of biodiversity and it may threaten the conservation and function of ecology as well as the welfare of mankind. Intense habitation has been made around the Nakdong River basin area that this study has analyzed the habitat density of nutria for the subject of 3 survey sites in the Nakdong River basin area. As a result of survey on habitation density in 2011 and 2012, under St.1 it was shown $2.01{\pm}0.21$/ha in 2011 and $0.69{\pm}0.55$/ha in 2012. Under St.2, it was shown $0.91{\pm}0.37$/ha in 2011 and $0.55{\pm}0.39$/ha in 2012. Under St.3, it was shown $5.31{\pm}0.72$/ha in 2011 and $3.99{\pm}2.31$/ha in 2012. The wet survey areas of St.1 and St.3 had shown relatively high habitation density compared to St. 2, the river survey area, and the average annual habitation density of the survey area was $2.74{\pm}2.29$/ha in 2011 and $1.74{\pm}1.18$/ha in 2012 that it has shown slightly reducing trend. As a result of measuring the morphology by capturing the habitation individuals, the average body length of adults is $92.23{\pm}9.41cm$, the length from the head to body for $53.90{\pm}5.15cm$, tail length for $38.33{\pm}4.83cm$, hind foot length for $13.82{\pm}1.00cm$, front foot length for $6.02{\pm}0.56cm$, and weight for $5.48{\pm}1.08kg$. As a result of comparing the types between genders, male showed a slightly higher figure in all parts compared to female and it showed significantly difference in total body length, head-body length, front foot length and total weight. As a result of analysis for each head-body length, other measured parts, weight and relativity for each measured part, all bodily part is shown to have the higher volume of correlations. The condition index of individuals in the survey area was shown in the average of $35.67{\pm}4.78$ with female for an average of $36.60{\pm}5.19$ and male for an average of $34.73{\pm}4.34$. The winter temperature in the southern area of Korea is considered for not greatly impacting on the habitation and development of nutria that, if there is no artificial control, it is considered to have certain concern of showing drastic breeding and territory expansion for the habitation group.

• Journal of Environmental Impact Assessment
• /
• v.26 no.1
• /
• pp.1-10
• /
• 2017

The study was carried out to understand the inhabiting status and biological features of nutria (Myocastor coypus) in the Jeju Island from May, 2013 to August, 2016. Five individuals were captured by traps and two individuals were collected in dead. Of the 7 individuals, those whose bio-information could not be known were excluded to perform autopsy of the rest of them. The results from morphological, cranial and anatomical analyses, it was found that the females achieved sexual maturation but had no breeding experience. An adult male showed similar sizes to those found in the Korean Peninsula. After collecting the 7 individuals in 2013, 1 nutria individual was filmed by the scouting camera in May, 2014 but not captured. The long-term investigation of the research area found no inhibiting individual. It is deemed the nutria was either died of natural death or migrated. In order to establish a proper nutria control, the environmental characteristics of Jeju Island should be considered where indigenous and introduced species coexist in a limited space. Our findings will provide helpful information for understanding biological features of nutria and planning protection program of natural ecosystems of Jeju Island.

• Journal of Environmental Impact Assessment
• /
• v.22 no.5
• /
• pp.491-511
• /
• 2013

In this study, three survey areas in Changnyeong, Miryang and Jinju of the confirmed the habitation of nutria and carried out the performance on the plant diet resource. From the habitat trace survey in the nutria habitat, a total of 336 trace points was shown. There were 181 trace points (54%) confirmed from St. 1 as the highest showing, followed by 52 trace points (15.4%) from St. 2, and 103 trace points (30.6)% from St. 3. The vascular plants distributed in the habitat area were a total of 182 taxonomic group with 57 families, 99 genus, 16 hybrids, and 1 race. The vascular plant living types in the habitat area are 1-year plant (Th, Th(w)) for 63class groups (34.6%), hemicryptophyte (H) for 42class groups(23.1%). plants, trees, crop plants were included. As a result of analyzing the overseas research cases on the diet plants of nutria, there are 195 taxonomic groups in a total of 39 families, 126 genus, 183 breeds, and 12 hybrids. In the study areas, feeding the plants was confirmed by the 7 taxonomic groups, aquatic plant, terrestrial From the total of 182 taxonomic groups discovered in the habitat area, 20 class groups, in 3 habitation region, 10 class groups of commonly appearing 49 class groups were shown to be the breed confirmed for diet in existing case studies, and assuming from it basis, the nutria habitating in the survey area is considered to have the supply of diverse diet resource to have flawless habitation. This is implication of having potential breeding possibility.

• Journal of Environmental Impact Assessment
• /
• v.27 no.1
• /
• pp.33-55
• /
• 2018

It has been noted that the main cause of biodiversity loss is influx of alien species. Specifically, habitats destruction, economic loss, and human injury are increasing due to invasive alien species. There were 2,167 alien species in Korea. 21 alien species of extraterrestrials including Lycorma delicatula, Solenopsis invicta, Myocastor coypus, and Spartina alterniflora at high risk through ecological risk assessment, are designated as invasive alien species. Alert species, which may have negative impact on ecosystems when they are introduced into the country, are assigned to 127 species through the ecosystem risk evaluation. To list such alien species to prevent invasion of alien species in advance, and to minimize damage caused by imported alien species, a national level management system called the Conservation and Use of Biological deversity Act was established, but there is a lack of a systematic management system in accordance with degree of risk. There is also a risk assessment chart should be developed thatreflects ecological characteristics of each taxon and evaluation criteria in predicting the risk.

• Korean Journal of Environment and Ecology
• /
• v.36 no.6
• /
• pp.582-591
• /
• 2022

This study was conducted to eliminate Myocastor coypusMolina, 1782 (Nutria) from Jeju Special Self-Governing Province, South Korea. Habitat identification and eradication were carried out from September to November 2013, and a survey was carried out until June 2022 to check whether the eradication was successful. The habitat was identified with unmanned cameras, interviews, and literature surveys, and the capture was performed using the trapping method with food to attract nutria to the habitat area. The study area for the follow-up survey, which was set relatively wide considering nutria's home range, included wetlands and rivers within 4.0 km² of the habitat area (eradication area). As a result, nutria's habitat was confirmed only at Songdang Ranch, Songdang-ri, of Jeju Island, with traces of habitat (footprints, excrement, and burrows) confirmed in waterways and ponds within the pasture. Eight individuals were captured, including four females, three males, and one individual in too advanced a state of decay to identify the sex. The follow-up survey thoroughly investigated the habitat and its surroundings, focusing on three areas with permanent water, Seongeup Reservoir, Cheonmi Creek, and Molsuni Pond, but no signs of habitat were identified. Therefore, it is determined that nutria inhabiting Jeju Island has been completely eradicated. It is believed that the successful eradication of nutria in the Jeju Special Autonomous Region was possible due to a synergy between 1) the eradication of nutria at the beginning of the settlement phase through rapid capture after confirming the nutria habitat and 2) the delayed expansion period because of rare presence of wetlands, where water is constantly stagnant, on Jeju Island. These results imply that quickly identifying the ecological characteristics of the species and preventing disturbances before they or at the beginning of the ecological disturbance through control and eradication at the initial stage of settlement before the expansion stage is an effective measure to cope with the influx of alien species.

• Journal of Veterinary Science
• /
• v.21 no.1
• /
• pp.1.1-1.4
• /
• 2020

Tumor incidence in wild mammals is reportedly very low. Wild nutria, a large rodent, is known to carry many infectious diseases, but rarely exhibits neoplastic diseases. We necropsied a male wild nutria and found a large nodular mass in the left inguinal region, adjacent to the penis. Histopathologically, the mass was diagnosed as preputial gland adenoma. Spontaneous preputial gland adenomas are extremely rare in all animals. Moreover, reports of tumors in nutrias have been limited to adenocarcinomas of the lungs and uterus, as well as subcutaneous fibromas. Here, we describe preputial gland adenoma in a wild nutria.