IUCN/SSC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Volume 35 Issue 3 October 2018)
Abstracts
The Conservation Status of Otters in Southwest Tanzania
Pages 134 - 147 (Article)
Daniela W. De Luca, Maeva Dewas, Noah Mpunga, Sophy J. Machaga and Guy Picton Phillipps
Two species of otters are confirmed in Tanzania, the African clawless (Aonyx capensis) and the spot-necked (Hydrictis maculicollis). Both are listed as ‘near-threatened’ in the IUCN Red List, with the main threats linked to pressures exerted on their habitat and food resources by a growing human population. Despite scant details of their Tanzanian distributions, our recent work shows that both species are more widespread than previously believed. We investigated distribution and conservation status in two highly populated areas in southwest Tanzania, Mt. Rungwe and Sao Hill. Rainy and dry season surveys for spraint sites included rivers, lakes and swamps, with data collected on associated dietary items and habitat features. Results indicated that species presence and distribution are not significantly affected by seasonality and that they can thrive as long as retaliatory hunting is prevented. Habitat quality should be monitored to avoid deterioration of escape cover. The nature of threats and the conservation of both species are discussed.
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Observations of the Variation in Group Structure of two Urban Smooth-Coated Otter Lutrogale perspicillata Groups in the Central Watershed of Singapore
Pages 148 - 154 (Report)
Max De Yuan Khoo and N. Sivasothi
The population and distribution of the smooth-coated otter Lutrogale perspicillata in Singapore have increased since 1998. In recent years, the species has established itself in urban areas with high human exposure within the Central Watershed of Singapore. The ease of following L. perspicillata in such areas has facilitated the monitoring of two urban groups, allowing the temporal variation in their group structures to be scrutinized. Field observations from two studies, and observations from the ground between December 2014 and December 2017, were compiled. Breeding pairs from both groups each gave to a total of seven litters of pups, with a mean litter size of 4.86. A change in group behaviour from pre-pregnancy, pre-natal and to post-natal were observed. Natural mortality resulting from intraspecific aggression and other natural causes, and an instance of anthropogenic mortality, were observed. Wild records of parturition, litter size, movement pattern and mortality are rare for this species from anywhere in its world range.
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Evidence of the Presence of Lutra lutra in Taleqan, Alborz Province, Iran
Pages 156 - 158 (Short Report)
Sina Mohtasebi and Farbod Tabatabaei
Little information is available for the Eurasian otter (Lutra lutra) in Iran. According to previous data in national environmental organization of Iran, they are distributed near rivers and water source of northern, north eastern provinces and some areas of southern provinces. Their population is decreasing due to environmental hazards
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Analysis of the Steroid Hormone Levels in the Eurasian Otter (Lutra lutra) by using Fecal Samples
Pages 159 - 170 (Article)
Yumiko Okamoto, So-Young Jung, Sung-Yong Han, Hyo-Dong Han, Keiko Shimizu, Hyeong-Hoo Kim, Kyung-Yeon Eo, Keun-Woo Park, Hyun-Taek Oh and Junpei Kimura
The population of the Eurasian otter has declined due to habitat destruction, pollution and urbanization. Studying reproductive physiology is one of the most essential things for conservation. However, there is no report which aims to understand basic reproductive physiology of this species in Korea. Hence, fecal samples of 6 Eurasian otters kept in Korea were collected for 7-12 months to analyze steroid hormone levels to understand their basic reproductive physiology. It was succeeded to identify individual feces by fecal markers for the first time in this species in Korea. A young female otter showed clear increases in fecal estradiol and progesterone levels and both of hormone levels were much higher than that of a subadult and old female otters. The average of interval period of each peak in progesterone of a young female was 43.5 days. Pseudopregnancy was not observed. Fecal testosterone level of an old male otter was as high as that of a young male otter. However, fecal testosterone level of a subadult male otter was very low. Steroid hormone levels of otters rose between January and November in this study, which mostly coincides with a study that reports the reproductive season of Eurasian otters in Korea is from January to September. Attempt was successful in monitoring endocrine traits by using fecal samples and breeding season of Eurasian otters in Korea. This study represents the first comprehensive examination of endocrine traits of Eurasian otters in Korea, and these findings may contribute to the conservation and management of this species.
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Population Structure, Distribution, and Habitat Use of Smooth-Coated Otters Lutrogale perspicillata in Singapore
Pages 171 - 182 (Report)
Max De Yuan Khoo and N. Sivasothi
The population and distribution of smooth-coated otters (Lutrogale perspicillata) in Singapore has increased since their return in 1998, but their population structure, distribution, and habitat use have not been quantified. A nation-wide field study (land surveys, boat surveys and camera trapping) at 15 sites, along with the collection of L. perspicillata records from the public, were conducted for six months (August 2016 to January 2017). The current study reveals at least 79 individuals in Singapore from 11 groups. The population in Singapore is growing, and consists of 58.2% adults and 41.8% sub-adults or pups. The average group size is 7.2, with groups ranging from two to 14 individuals. L. perspicillata occupy a wide variety of aquatic habitats including mangroves, coasts, reservoirs, rivers, and canals. They have adapted to using urban structures, and have survived and reproduced in urban environments, which shows that they are urban adapters
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