Main Article Content
Living in different aquatic ecosystems, otters play a vital role in maintaining aquatic species assemblages, particularly fish communities. Thus their wellbeing indicates the health of wetland ecosystems. Smooth-coated Otter Lutrogale perspicillata, a piscivorous mustelid, is widely distributed across Asia. Its population is declining due to habitat transformation, pollution and hunting. This study aimed to understand the ecological requirements of the species by assessing its distribution and its determinants, population and diet composition along the Cauvery River in Hosur and Dharmapuri Forest Divisions. Through monthly extensive surveys between December 2010 and February 2011, covering 62.5 km of Cauvery from the Karnataka border to Palar River junction, this study identified and mapped a 31 km stretch from Dubguli (Yellolapatti) to Biligundlu (Musulumaduvu) as an otter distribution area. Comparison of ecological parameters including bank type, water depth, river width, human disturbance, vegetation cover and water current with the distribution pattern of otters across 125 blocks revealed that water depth and vegetation cover influenced otter distribution positively, while human disturbance had negative influence (these three variables explained 54% of variation in otter distribution). Based on direct sightings, seven different groups consisting of 36 individuals were estimated as the minimum population. The mean group size was 3.8 ± 0.16 (range: 2–7) individuals. Twenty-one otter spraints were analyzed to determine diet composition, revealing that otters feed on insects, molluscs, crabs, fish, frogs, reptiles and birds. Fish constituted the bulk of otter diets. Conservation measures like reducing anthropogenic pressures (e.g., fishing, cattle pens, tourism), increasing awareness of sustainable fishing to stakeholders, and instituting long-term monitoring programs are suggested for the long-term conservation of otters in the study area.
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors own the copyright to the articles published in JoTT. This is indicated explicitly in each publication. The authors grant permission to the publisher Wildlife Information Liaison Development (WILD) Society to publish the article in the Journal of Threatened Taxa. The authors recognize WILD as the original publisher, and to sell hard copies of the Journal and article to any buyer. JoTT is registered under the Creative Commons Attribution 4.0 International License (CC BY), which allows authors to retain copyright ownership. Under this license the authors allow anyone to download, cite, use the data, modify, reprint, copy and distribute provided the authors and source of publication are credited through appropriate citations (e.g., Son et al. (2016). Bats (Mammalia: Chiroptera) of the southeastern Truong Son Mountains, Quang Ngai Province, Vietnam. Journal of Threatened Taxa 8(7): 8953–8969. https://doi.org/10.11609/jott.2722.214.171.12453-8969). Users of the data do not require specific permission from the authors or the publisher.
Anoop, K.R. & S.A. Hussain (2005). Food and feeding habits of smooth-coated otters (Lutra perspicillata) and their significance to the fish population of Kerala, India. Journal of Zoology (London). 266: 15–23. https://doi.org/10.1017/S0952836905006540
Anoop, K.R. (2001). Factors affecting habitat selection and feeding habits of Smooth-coated Otter (Lutra perspicillata) in Periyar Tiger Reserve, Kerala. M.Sc. Thesis. Wildlife Institute of India, Dehra Dun, India, 62 pp.
Balasubramanian, M. (1989). Food habits of Smooth-coated Otters Lutra perspicillata in Mudumalai Wildlife Sanctuary, Tamil Nadu. Unpublished M.Sc. Dissertation. A.V.C. College, Mannampandal, Mayiladuthurai, Tamil Nadu, 20 pp.
Baskaran, N., G. Nayak, M. Saravanan, K. Senthilkumar, S.R. Chandramouli & K.G. Avinash (2010). Vertebrate faunal diversity in Hosur Forest Division and its contiguous habitats in Dharmapuri Forest Division of Tamil Nadu. Summary Report Tamil Nadu Forest Department, May 2010, 31 pp.
Burton, M. (1968). Wild Animals of the British Isles, pp. 131–136. In: The Otter. Warne, F. and Co Ltd, London.
Channin, P. (1985). The Natural History of Otters. Christopher Helm, London, 179 pp.
Chehebar, C. (1985). A survey of the Southern River Otter Lutra provocax Thomas in Nahuel Huapi National Park, Argentina. Biological Conservation 32: 299–307. https://doi.org/10.1016/0006-3207(86)90056-X
CITES (2019). CITES 18th Conference of Parties (CoP) held in Geneva on 26 August 2019.
de Silva, P., W.A. Khan, B. Kanchanasaka, L.I. Reza, M.M. Feeroz & O.F. Al-Sheikhly (2015). Lutrogale perspicillata. The IUCN Red List of Threatened Species 2015: e.T12427A21934884. Downloaded on 19 November 2021. https://doi.org/10.2305/IUCN.UK.2015-2.RLTS.T12427A21934884.en
Erlinge, S. (1972). The situation of the otter population in Sweden. Viltrevy 8: 379–397.
Green, J., R. Green & D.J. Jefferies (1984). A radio-tracking survey of otter (Lutra lutra) on a Perthshire river system. Lutra 27: 85–145. https://www.iucnosgbull.org/Volume14/Volume14 Issue2.pdf
Hussain, S.A. (1993). Aspects of the ecology of Smooth-coated Indian Otter (Lutra perspicillata) in National Chambal Sanctuary. PhD Thesis, Aligarh Muslim University, xxiii+206 pp.
Hussain, S.A. (1996). Group size, group structure and breeding in Smooth-coated Otter (Lutra perspicillata) Geoffroy in National Chambal Sanctuary. Mammalia 60(2): 289–297.
Hussain, S.A. & B.C. Choudhury (1997). Distribution and status of the Smooth-coated Otter (Lutra perspicillata) in National Chambal Sanctuary, India. Biological Conservation 80: 199–206.
Jayaram, K.C. (2000). Kaveri Riverine System: An Environmental Study, Madras Science Foundation, Chennai.
Jayaram, K.C. (1994). The freshwater fishes of India, Pakistan, Bangladesh, Burma and Sri lank — A Handbook. Zoological Survey India, Calcutta, xxii+475 pp.
Jefferies, D.J. (1966). The value of otter (Lutra lutra) surveying using spraints: an analysis of its success and problems in Britain. Journal of the Otter Trust 1(9): 25–32.
Jenkins, D. & G.O. Burrows (1980). Ecology of otters in northern Scotland. III. The use of faeces as indicators of otter (Lutra lutra) density and distribution. Journal of Animal Ecology 49: 755–774. https://doi.org/10.2307/4225
Jenkins, D., J.G.K. Walker & D. McGowan (1979). Analysis of the otter (Lutra lutra) faeces from Deeside, N.E. Scotland. Journal of Zoology, London 187: 235–144. https://doi.org/10.1111/j.1469-7998.1979.tb03946.x
Knudsen, G.J. & J.B. Hale (1968). Food habits of otters in Great Lakes Region. Journal of Wildlife Management 32(10): 89–93. https://doi.org/10.2307/3798240
Kruuk, H. & J.W.H. Conroy (1987). Surveying the otter (Lutra lutra) populations: a discussion of problems with spraints. Biological. Conservation 41(3): 179–183. https://doi.org/10.1016/0006-3207(87)90101-7
Kruuk, H. 1992. Scent marking by otters (Lutra lutra): Signaling the use of resources. Behavioural Ecology 3: 33–140.
Mason, C.F. & S.M. Macdonald (1986). Otters – ecology and conservation. Cambridge University Press, 248 pp.
Mason, C.F. & S.M. Macdonald (1987). The use of spraints to survey populations of otters (Lutra lutra). Biological Conservation 41(3): 167–177.
Meena, V. (2002). Otter poaching in Palni Hills. Zoos Print Journal. 17: 696–698.
Melquist W.E. & A.E. Dronkert (1987). River otter North Bay, Ontario, Canada, pp. 625–641. In: Novak, M.J., A. Baker & M.E. Obbard (eds.). Wild Furbearer Management and Conservation in North America.
Melquist, W.E. & M.G. Hornocker (1983). Ecology of river otters in west central Idaho. Wildlife Monograph 83: 1–60.
Menon, V. (2003). A Field Guide to Indian Mammals. Penguin India and Dorling Kindersley, India, 164 pages.
Nagulu, V., C. Srinivasulu & R. V. Vasudeva (1999a). Status of otter in southern Indian states: an updated report 1999. In: Envis Bulletin: Wildlife and Protected Areas 2(2): 71–73.
Nagulu, V., R.V. Vasudeva & C. Srinivasulu (1999b). Curative property of otter blood - a belief. IUCN Otter Specialist. Group Bulletin 16(1): 44.
Nolet, B.A., D.E.H. Wansink & H. Kruuk (1993). Diving of otters (Lutra lutra) in a marine habitat: use of depths by a single-prey loader. Journal of Animal Ecology 62: 22–32. https://doi.org/10.2307/5479
Norris, D. (1974). A study of the otter (L. lutra) on the R. Fergus from July to September 1974. Unpublished Wildlife Service Report.
Ottino, P. & P. Giller (2004). Distribution, density, diet and habitat use of the otter in relation to land use in the Argali valley, Southern Ireland. Biology and Environment: Proceedings of the Royal Irish Academy 104(1): 1–17
Pardini, R. (1998). Feeding ecology of the Neotropical River Otter (Lontra longicaudis) in an Atlantic Forest Stream, south-eastern Brazil. Journal of Zoology (London.) 245: 385–391. https://doi.org/10.1111/j.1469-7998.1998.tb00113.x
Paterson, A.W. & A.K. Whitfield (2000). Do shallow-water habitats function as refugia for juvenile fishes? Estuarine and Coastal Shelf Science 74: 263–273. https://doi.org/10.1006/ecss.2000.0640
Pocock, R.I. (1949). The Fauna of British India, including Ceylon and Burma, Vol. 2, Mammals. Taylor and Francis, London, xxxi+459 pp.
Prater, S.H. (1971). The Book of Indian Animals, 11th impression, pp. 146–154. Bombay Natural History Society and Oxford University Press, Calcutta.
Raha, A. & S.A. Hussain (2016). Factors affecting habitat selection by three sympatric otter species in the southern Western Ghats, India. Acta Ecologica Sinica 36: 45–49. https://doi.org/10.1016/j.chnaes. 2015.12.002
Reuther, C. (1999). From the Chairman’s desk. IUCN Otter Spec. Group Bulletin 16: 3–6.
Rowe-Rowe, D.T. (1977). Food ecology of otters in Natal, South Africa. Oikos 28: 210–219.
Shariff, S.M. (1984). Some observations on otters at Kuala Gula, Perak and National Park, Pahang. Journal of Wildlife Parks 43: 2075–2488.
Shenoy, K. (2002). Habitat selection and diet composition of Smooth-coated Otters (Lutra perspicillata) in the Cauvery Wildlife Sanctuary, Karnataka, India. M.Sc. Dissertation. Pondicherry University, Pondicherry, India.
Shenoy, K. (2005). Otters in the River Cauvery, Karnataka. Occasional report no. 11. Wildlife Trust of India, 42 pp.
Shenoy, K., S. Varama & K.V.D. Prasad (2006). Factors determining habitat choice of the smooth-coated otter, Lutra perspicillata in a south Indian river system. Current Science 91(5): 637–643.
Sivasothi, N. (1995). The status of otters (Carnivora: Mustelidae: Lutrinae) in Singapore and Malaysia, and the diet of smooth-coated otter (Lutrogale perspicillata) in Penang, West Malaysia. M.Sc. Thesis National University of Singapore, 86 pp.