• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.525-528
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• 2013

River otter(Lutra lutra) are listed as endangered species and Natural monument in Korea, and this study examined the possibility of extinct of river otter in Hongchon river using with the application of Population Viability Analysis (PVA) technique. In Hongchon river areas population was estimated 9 individuals for the last 1999-2005 years and PVA analysis was done for the next 10 years using the average population of 9. Using the initial population the river otter was estimated 30% of extinct for the next 10 years. This estimation was quite low considering water pollution and construction of highways. Also PVA only used population size lacking in other life history information. Nonetheless river otter population can be in risk of extinction if the current construction of crossovers, cement bank are maintained. Long term information regarding life history needs essential.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.395-399
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• 2009

Radiotelemetry device was surgically implanted in the abdomen of a Eurasian river otter (Lutra lutra). Behaviors of the otter, hospitalized after surgical implantation were also observed. The surgical techniques involved an incision in the paralumbar fossa to introduce a radiotelemetry device into the abdominal cavity. Thirteen behaviors of the otter during hospitalization following abdominal surgery were observed and the time budget of each behavior and the times at which each behavior seems to appear most frequently were measured. This report could provide surgical techniques involving intra-abdominal implantation in otter and basic information associated with otter's behaviors during hospitalization.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.1-6
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• 2022

Among the 13 species of otters in the world, only one Eurasian otter (Lutra lutra) is found in South Korea. In the Korean Peninsula, otter pelts were historically valuable and expensive commodities used for international trade, and otters have long been poached as hunting animals. Recent rapid economic development in South Korea has increased habitat fragmentation and loss, creating a continuing threat to the natural environment. Otters live only in the area of rivers and streams as a family group and are territorial (linear habitat). Due to these limited conditions of otter habitat, the population size of otter is lower than that of onshore mammals. According to recent research, DNA analyses using microsatellite markers have shown that only approximately 7-21 otter individuals inhabit river systems for a length of 50-230 km. Korea's urban streams are associated with many threats that hinder otters from inhabiting them. Many areas around the urban streams are surrounded by high concrete riverbanks, and the risk of roadkill is also high. Nevertheless, ecological restoration projects in the urban rivers will contribute greatly to the stable inhabitation of otters. Detailed otter conservation strategies, such as the elimination of threat factors, improvement of habitat environment, and restoration of food resources and shelter, will provide a positive restoration effect on otter and river ecosystems as well.

• Journal of Environmental Science International
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• v.26 no.12
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• pp.1341-1353
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• 2017

This study aimed to identify the aquatic and riparian factors associated with the presence/absence of the Eurasian otter in the Nakdong river basin, where the species is relatively more abundant than other otter species. Environmental factors and presence records were collected. Geographical Information System technology and chi-square test were used to compare environmental gradients in aquatic and riparian factors between presence and absence sites. Aquatic habitat attributes were evaluated with natural riverside sandbars and channel crossing artificial structures, the ratio of channel width to alluvial plain width, riverbed substrate, and flow diversity. Riverbank characteristics, bank materials, man-made embankment types, and land use/land cover of inland and riverside areas were selected as riparian habitat attributes. Compared to the aquatic attributes, riparian attributes were highly significant when assessing otter presence and absence sites, suggesting that conservation of suitable riparian areas to provide maternity and resting areas for otter species is essential in the Nakdong river basin. None of the aquatic attributes examined were statistically significant when evaluating otter presence or absence. These results indicate that the presence of suitable riparian area for resting and reproduction habitats is more critical to the presence of Eurasian otter than food availability in aquatic areas. To inform implementation of effective conservation actions, broad-scale factors, such as watershed attributes, would be needed to further assess habitat conditions of the Eurasian otter.

• Journal of Animal Science and Technology
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• v.56 no.5
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• pp.16.1-16.9
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• 2014

Fatty acids (FA) have recently been used in several studies to infer the diet in a number of species. While these studies have been largely successful, most have dealt with predators that have a fairly specialized diet. In this paper, we used FA analysis as a tool to infer the diet of the nearctic river otter (Lontra canadensis). The river otter is an opportunistic predator known to subsist on a wide variety of prey including, fishes, crayfish, molluscs, reptiles and amphibians, among others. We analyzed the principle components of 60 FA from otters and 25 potential prey species in Illinois, USA. Prey species came from 4 major taxonomic divisions: fishes, crayfish, molluscs and amphibians. Within each division, most, but not all, species had significantly different profiles. Using quantitative FA signature analysis, our results suggest that, by mass, fish species are the most significant component of Illinois River otters' diet ($37.7{\pm}1.0%$). Molluscs ranked second ($32.0{\pm}0.8%$), followed by amphibians ($27.3{\pm}4.3%$), and finally, crayfish ($3.0{\pm}0.6%$). Our analysis indicates that molluscs make up a larger portion of the otter diet than previously reported. Throughout much of the Midwest there have been numerous otter reintroduction efforts, many of which appear to be successful. In regions where mollusc species are endangered, these data are essential for management agencies to better understand the potential impact of otters on these species. Our analysis further suggests that quantitative FA signature analysis can be used to infer diet even when prey species are diverse, to the extent that their FA profiles differ. Better understanding of the otter's metabolism of FA would improve inferences of diet from FA analysis.

• Journal of Environmental Impact Assessment
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• v.14 no.6
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• pp.377-385
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• 2005

The Eurasian otter(Lutra lutra) is listed as No. 330 in natural monument. To manage and conserve habitat for otters, it is critical to understand which habitat components are important for otters. The objectives of this study were to analyze otter habitat characteristics in accordance with land-cover map. We investigated otter spraints and sprainting site in Geoje Island from January to December, 2004. with GPS coordinates. The analysis of otter habitat use pattern was used by Arcview ver. 3.2 with 1: 25,000 Topology Map and field data. Otter habitat use was strongly related to sites in riparian vegetation riparian(dam or river) structures. In this study, Gucheon was a site with high coverage of riparian vegetation and unconfined channels, thus recording higher number of spraint densities than those of Yeonchocheon. Yeonchocheon was under construction at lower stream areas so that otter habitat use was limited. This study suggests that securing suitable forests and riparian vegetation zone is essential for conservation of otters.

• Journal of Ecology and Environment
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• v.47 no.2
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• pp.42-48
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• 2023

An adult male Eurasian river otter (Lutra lutra) with ataxia and lethargy was rescued. Through the necropsy of this otter with neurological symptoms, a broad range of vascular damage caused by mercury toxicity in several organs, hepatocellular necrosis, and vacuolation in the brain. In mercury examination, liver, kidney, and hair showed values of 0.878 ± 0.027, 1.807 ± 0.049, and 5.712 ± 0.102 ㎍/g, respectively. Compared with certified reference material, it was confirmed that the concentration of mercury were 6.7 times, 13.7 times, and 43.3 times higher, respectively. When the symptoms and diagnosis results were comprehensively reviewed, this otter's demise was revealed due to mercury poisoning. The mercury concentration in the liver does not exceed the lowest observed effect level of 3.4 ㎍/g. However, even at low concentrations, long-term accumulation can cause symptoms including neuropathy, and the possibility that these heavy metals have accumulated in other wild animals cannot be ruled out. It seems that continuous monitoring using sentinel animals is necessary.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.402-406
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• 2015

This study aims at favorable environmental conditions by river otter residing in Hongcheon river ecosystems using spraints along the river. Otter spraints were indicative of habitat use pattern and marking a territory in the areas. Nae-chon and Kuneob-chon river otter spraints were collected totaling 478 with 8 times during 2009-2011, and based on the number river use patterns were analyzed with the technique of index of dispersion. Results with larger than one indicated that river otter habitat use pattern were not random; instead they used preferred areas for habitat use. 'I' values greater than one indicate a clumped distribution and lower than one indicate random distribution. This study also demonstrated that we need a sophiscated linear model that should be developed to identify key habitat elements in river ecosystems.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.315-321
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• 2005

The population of river otter (Lutra lutra) has been declined most of the world due to hunting, habitat destruction and indirect or direct influences of eutrophication, acidification and toxic chemicals. This study is conducted to identify the population decline of river otter in Korea with relation to environmental pollution caused by accumulation of heavy and flared metals. The field survey was conducted during Jan~Dec, 2004 at a monthly basis by collecting spraints. A total of 228 spraints were collected and analysis was done by ICP-AES. The concentrations of fourteen metals (Cr, Zn, Cd, Pb, Ni, Fe, Co, Mn, Mg, Cu, Al, Ba Hg, As) have been determined. Annual concentrations of Cd $(1.38{\mu}g\;g^{-1}),\;Zn\;(599.06\;{\mu}g\;g^{-1}),\;Pb\;(5.54\;{\mu}g\;g^{-1})$ at Gucheon were higher than those of Yeonchocheon. Concentrations of $Cr\;(5.01{\mu}g\;g^{-1}),\;Ni\;(1.91{\mu}g\;g^{-1}),\;Co\;(0.25{\mu}g\;g^{-1})$ were higher at Yeonchocheon. Most metals in winter were significantly increased (P<0.05) as season progressed from spring to winter. $Pb\;(15.58{\mu}g\;g^{-1}),\;Cu\;(15.15{\mu}g\;g^{-1}),\;a;Guchoen\;and\;Cr\;(5.77{\mu}g\;g^{-1})$ at Yeonchocheon were high in the downstream of winter.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.4
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• pp.1-14
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• 2024

Otters, designated as Class I endangered wildlife due to population declines resulting from urban development and stream burial, have seen increased appearances in freshwater environments since the nationwide ban on stream filling in 2020 and the implementation of urban stream restoration projects. There is a pressing need for scientific and strategic conservation measures for otters, an umbrella and vulnerable species in aquatic ecosystems. Therefore, this study predicts potential otter habitats using the species distribution model MaxEnt, focusing on Hwangguji Stream in Suwon, and proposes conservation strategies. Otter signs were surveyed over three years from 2019 to 2021 with citizen scientists, serving as presence data for the model. The model's outcomes were enhanced by analyzing 'river nature map' as a boundary. MaxEnt compared the performance of 60 combinations of feature classes and regularization multipliers to prevent model complexity and overfitting. Additionally, unmanned sensor cameras observed otter density for model validation, confirming correlations with the species distribution model results. The 'LQ-5.0' parameter combination showed the highest explanatory power with an AUC of 0.853. The model indicated that the 'adjacent land use' variable accounted for 31.5% of the explanation, with a preference for areas around cultivated lands. Otters were found to prefer shelter rates of 10-30% in riparian forests within 2 km of bridges. Higher otter densities observed by unmanned sensors correlated with increasing model values. Based on these results, the study suggests three conservation strategies: establishing stable buffer zones to enhance ecological connectivity, improving water quality against non-point source pollution, and raising public awareness. The study provides a scientific basis for potential otter habitat management, effective conservation through governance linking local governments, sustainable biodiversity goals, and civil organizations.