IUCN/SSC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Abstracts
The Status of the Eurasian Otter (Lutra lutra) In Central Asia: A Literature Review
Pages 106 - 121 (Review)
Melissa Savage, Aleksey Oleynikov, Gleb Sedash, and Li Fei
The Eurasian otter (Lutra lutra) is rare in Central Asia. Otter populations are small and fragmented and appear to be declining in most parts of the region. Diminishing freshwater resources, high human population density in river valleys, river pollution, and a weak focus on nature conservation, make the long-term survival of the species in the region highly threatened. Here, we review the available literature about the Eurasian otter from recent decades in Kazakhstan, Uzbekistan, Kyrgyzstan, Turkmenistan, Tajikistan, Afghanistan, and far northwestern China. Central Asia can be considered a “white spot” in terms of otter research, with extremely limited available data suggesting a compelling need for further study and conservation measures.
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Large-Scale Identification of Microsatellite Loci from Multiple Otter (Mammalia, Carnivora, Lutrinae) Species using Whole Genome Sequence Data
Pages 120 - 132 (Article)
Vera De Ferran, Channelle Ee Eun Chua, Philip Johns, Eduardo Eizirik, and Klaus-Peter Koepfli
The development of molecular studies on elusive, rare, and/or poorly known species faces challenges due to the lack of suitable markers. Species-specific microsatellite markers minimize bias, offer better performance, and are cost-effective, aiding the development of population genetic studies. The use of whole-genome sequences allows for the development of species-specific microsatellite markers and their survey in closely related species, enabling the discovery of shared markers that can facilitate comparative studies. Lutrinae includes 14 extant species of otters. Despite their worrisome conservation status, due to inherent characteristics of these species that make their study difficult by traditional methods, many of them lack reliable population genetic data, limiting conservation efforts. In this study, we employed a multi-taxon approach to identify a large number of novel microsatellite loci for 11 of the 14 otter species, assessing whether the identified loci were shared among different taxa. We identified a total of 23,320 microsatellite loci across 11 species, which were reduced to 12,573 after stringent filtering criteria. Primer design was completed successfully for 420 and 259 unique loci, considering two minimum melting temperatures. We validated marker efficiency by testing the 81 loci designed for two Asian species. Of these, 51 loci yielded reliable microsatellite genotypes in both species, with 34 showing allelic variation in at least one of them. These results demonstrate that these markers are applicable in empirical genotyping for both their target species and closely related ones.
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Otter Density Correlates with Elevation in the Northern Annamite Mountains of Laos
Pages 133 - 150 (Article)
Jay White, Chayyang Chueva, and Thongla Latamsathit
Three species of otter have been identified in the People’s Democratic Republic of Lao (Laos): the smooth-coated otter (Lutrogale perspicillata), the Eurasian otter (Lutra lutra), and the small-clawed otter (Aonyx cinerus). All three species have experienced significant population declines and range constrictions globally and in Laos and require targeted conservation action to remain viable. We examined species composition and distribution in a protected area in the northern Annamite Mountains of Laos. We used camera trap detections and population density (by proxy of spraint density) to compare the significance of several natural and anthropogenic variables in predicting density and distribution. We hypothesized that we would find evidence of Eurasian and small-clawed otter at the study site and that they would show signs of niche segregation based on stream size and elevation– with small-clawed otter showing a preference for small high elevation streams and Eurasian otter, the opposite. We identified two species of otter: small-clawed and Eurasian otter but did not observe evidence of niche segregation between them. We did find a significant negative correlation of combined otter density (both species) with elevation, both species showing a preference for streams at lower elevations in the site. Additionally, we found no evidence of spatial avoidance of human activity. This suggests that lowland streams, including streams outside protected areas in Laos, are critical for otter conservation and deserve protection efforts, while high elevation streams may be more marginal as otter habitat.
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Distribution and Diet of Smooth-Coated Otters (Lutrogale perspicillata) in Tungabhadra Otter Conservation Reserve, Karnataka
Pages 151 - 161 (Report)
Niyaz Ahamed Kanekal, Jeyaraj Antony Johnson, and Syed Ainul Hussain
The Smooth-coated otter (Lutrogale perspicillata), is a top aquatic predator of Indian rivers, and is listed as Vulnerable on the IUCN Red List due to habitat degradation and declining populations. This study assessed the distribution and diet of the species in the Tungabhadra Otter Conservation Reserve (TOCR), a critical 34km stretch of the Tungabhadra River. Otter distribution was analyzed using sign surveys across 500 x 500m grids, recording direct sightings and indirect signs. The spatial distribution of otters was mapped using sign density and spatial autocorrelation analysis using Moran’s I test. Otter diet was examined through spraint analysis, identifying prey species using scale and skeletal remains. A total of 132 otter signs were recorded, indicating a strongly clustered distribution (Moran’s I = 0.99203). Spraint analysis (n=92) revealed a fish-dominated diet (97.87%), with Oreochromis mossambicus (37.70%) and Cyprinus carpio (11.48%) being the most consumed species. The findings indicate that otters preferentially inhabit specific areas within TOCR and depend largely on non-native fish species. This study provides insights into otter ecology in the region and highlights the importance of habitat conservation and fisheries management for otter conservation.
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