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Description |
Geographic Range [top]
Range Description: The Smooth-coated Otter is distributed throughout south Asia and southeast Asia. Its distribution is continuous from Indonesia, through southeast Asia, and westwards from southern China to India and Pakistan, with an isolated subpopulation in Iraq (Pocock 1941, Medway 1969, Hussain 1993). Though its current status in the Middle East is not known, its presence has been confirmed from Pakistan, India, Nepal, Bhutan, Bangladesh, southwest China, Myanmar, Thailand, Viet Nam, Malaysia (Penisular Malaysia, Sabah and Sarawak), and Indonesia (Kalimantan, Sumatra, Java) and Brunei (Mason and Macdonald 1986, Corbet and Hill 1992, Wozencraft 1993).
Countries occurrence:
Native:
Bangladesh; Bhutan; Brunei Darussalam; Cambodia; China; India; Indonesia; Iraq; Lao Peoples Democratic Republic; Malaysia; Myanmar; Nepal; Pakistan; Thailand; Viet Nam
Additional data:
? Upper elevation limit (metres): 700 ? Lower depth limit (metres): 5
Range Map: Click here to open the map viewer and explore range.
Population [top]
Population: Because of the secretive and nocturnal behaviour of Smooth-coated Otter, reliable estimates of its population are not available. In southeast Asia it is found in large groups (Foster-Turly 1992, Hussain 1993, Hussain 1996) where the basic family group consists of an adult female and her offspring, the father of the offspring, and older siblings may often join the group (Lekagul and McNeely 1988, Hussain 1996). The group size varies considerably between months and seasons, the group being largest during the monsoon period (Hussain 1996). Along the Chambal River in central India the group size ranges from 1-9 individuals (mean=4.62). During a study conducted in the Corbett Tiger Reserve, in north India an estimate of 41 individuals (35 adults and 6 juveniles) with a mean of 5.1±1.55 was recorded from the 85 km of river stretch within the Reserve (Nawab and Hussain 2007).
Current Population Trend: Decreasing
Additional data:
Habitat and Ecology [top]
Habitat and Ecology: The Smooth-coated Otter is essentially a plains otter. In the Indian subcontinent they are adapted to live even in the semiarid region of northwestern India and Deccan plateau (Prater 1971). Generally, it uses large rivers and lakes, peat swamp forests, mangroves and estuaries, and it even uses the rice fields for foraging (Foster-Turly 1992). In southeast Asia rice fields appear to be one of the most suitable habitats in supporting its viable populations (Melisch et al. 1996). However, they were more abundant in the mangroves of Kuala Gula, Malaysia as compared to the rain forest rivers (Shariff 1984).
Along the large rivers in India, the Smooth-coated Otters prefer rocky stretches since these stretches provide sites for den and resting. River stretches with bank side vegetation and marshes are used in proportion to their availability especially in summer as they provide ample cover while travelling or foraging. Open clayey and sandy banks are largely avoided as they lack escape covers (Hussain 1993; Hussain and Choudhury 1995, 1997). In the Tarai areas of the upper Gangetic plains the Smooth-coated Otters use seasonally flooded swamps during monsoon (July-September) and in early winter (October-February). Winter being the breeding season, the swamps are extensively used as natal den sites and nursery. By February-March the swamps begin to dry and the fish biomass appears to be depleted, consequently the otters move to the perennial rivers (Hussain and Choudhury 1997). In west Java, the Smooth-coated Otters prefer mangroves and tidal stretches of the rivers and rice fields. Freshwater swamps and coastal stretches lacking vegetation are avoided (Melisch et al. 1996). In rice fields and pond areas they prefer sites having moderate diversity of vegetation. Rivers with moderate to slow or stagnant water and water bodies having a width of 10-40 m are preferred. In Huai Kha Khaeng, Thailand, the Smooth-coated Otters extensively use the slowly meandering river near the dam and the dam itself (Kruuk et al. 1994).
The Smooth-coated Otter is predominantly a fish eater, but supplements its diet with shrimp/crayfish, crab and insects, and other vertebrates such as frog, mudskippers, birds and rats (Prater 1971, Foster-Turly 1992, Hussain and Choudhury 1998). In general, its diet is similar to that of Eurasian Otter. The range of fish in the diet varies from 75% to 100% (Tiler et al. 1989, Foster-Turly 1992, Hussain 1993, Melisch et al. 1996, Hussain and Choudhury 1998).
The Smooth-coated Otters exhibit the typical opportunistic feeding behaviour similar to the Eurasian Otter. Along the major rivers in India they eat more fish, often making up to 94% of the total diet (Hussain and Choudhury 1998), while along the coast in mangrove habitats and in rice fields it ranges between 75-100% (Foster-Turly 1992, Melisch et al. 1996). In west Java otters inhabiting mangrove areas eat more of crustaceans, around 22% of the scats contain remains of crab and shrimp where as in the paddy fields in Malaysia, along with fish they tend to eat more rice field rats Rattus argentiventer, represented in 23% of the spraints (Foster-Turly 1992).
Hussain (1993) identified 12 fish species from the spraint of Smooth-coated Otter from the Chambal River, of which seven species were eaten throughout the year. Rhinomugil corsula (Mugilidae) and Rita rita (Bagaridae) were the preferred species. At least eight species of fish were identified from the spraints from Malaysia (Foster-Turly 1992). Some of these include Gourami (Trichogater spp.), Climbing Perch (Anabis testudineus), catfish (Clarius spp.), snakehead (Channa spp.) and mudskipper (Gobioidei). In the rice fields they ate large amount of most common fish (Trichogater and Anabis spp.). The size of the fish consumed varied from 5-46 cm, often ranging between 15-30 cm (Wayre 1978). No significant relationship was found between the calorific values of the fish and the quantities consumed. Thus, the prey selection by Smooth-coated Otter is mainly influenced by its availability (Hussain 1993).
The Smooth-coated Otter attains sexual maturity at twenty-two months in captivity (Desai 1974). Yadav (1967) observed first litter at four years of age. In captivity they mate during August to October in water followed by prolonged playful bouts between partners (Desai, 1974, Naidu and Malhotra 1989). Copulation takes place several times daily. Males are polygamous mating with up to four females (Desai 1974). In the wild in northern India mating occurs in August-September and littering in November-December (Hussain 1993). Desai (1974) observed litter size of 2-5 (mean = 3.25). Similarly, Naidu and Malhotra (1989) observed litter size 1-5. The breeding schedule of Smooth-coated Otters in the wild in India corresponds with the captive records (Hussain 1993, 1996). Evidences of littering have been recorded in October and the cubs were seen out of the den in February. The mean litter size along the Chambal River was three (Hussain 1996).
Based on the percentage of active telemetry recordings, Hussain (1993) observed that the overall activity pattern of Smooth-coated Otters along the Chambal River in India was in the form of a bimodal curve in which two period of high activity were separated by a period of relative inactivity. This pattern of activity varied considerably among seasons. In summer, the relative period of inactivity was greater than in winter or monsoons. A significant difference was also found between day and night time activities in different seasons. Otters were more diurnal during winter than in summer or monsoon.
Hussain (1993) observed daily movements of four radio-implanted Smooth-coated Otters of different age and sex within their home range. Two types of movements were identified; small-scale movements associated with foraging in a restricted area close to dens, and more extensive travels between dens and foraging sites. Most of the movement was restricted between 250 to 1,500 m. A typical group of Smooth-coated Otter consisting of male, female, and up to four young ones require 7 to 12 km of river for their territory and an even longer stretch of shoreline if living along the coast (Wayre 1974). During a radio-tracking study along the Chambal River, India, the home range of all the otters tracked overlapped intensively. Among the radio-implanted otters, the maximum home range was observed in sub-adult male and the minimum in juvenile female and male. Among the non-tagged otters, the home range of female with cubs was estimated as 5.5 km. In case of the adult male it was estimated to be approximately 17 km (Hussain 1993). Along the Chambal River, the home range length and area of smooth-coated otter was less than that of Eurasian Otter, in Perthshire, Scotland and North American River Otter Lontra canadensis in Idaho (Melquist and Hornocker 1983), but larger than that of Eurasian Otter (Erlinge 1967) in Sweden.
Systems: Terrestrial; Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 10
Movement patterns: Not a Migrant
Use and Trade [top]
Use and Trade: Species is illegally utilized in wildlife trade.
Threats [top]
Major Threat(s): Major threats to Asian otter populations are loss of wetland habitats due to construction of large-scale hydroelectric projects, reclamation of wetlands for settlements and agriculture, reduction in prey biomass, poaching and contamination of waterways by pesticides. In most Asian countries although there has been increased human population during the last century, inadequate and ineffective rural development programmes have not been able to address the problems of poverty, forcing people to be more and more dependent on natural resources (Badola 1997). Consequently, most of the wetlands and waterways do not have adequate prey base for sustaining otter populations. Wetlands and waterways are polluted by eutrophication and accumulation of persistent pesticides such as chlorinated hydrocarbons and organophosphates through agricultural runoffs. Increased pesticide use is not only regarded as a major obstacle to the development of rice-fish culture, but also poses a danger to all predators feeding on aquatic prey in the area (Melisch et al. 1996). In the entire south and southeast Asia there is severe conflict between otters and humans, because of poverty and recent increase in aquaculture activities leading to indiscriminate killing of otters. Many important habitats of smooth otter have been lost to development activities. In southeast Asian countries, there does not seem to be any intentional otter trapping (Melisch et al. 1996) though it is prevalent in India, Nepal and Bangladesh.
Conservation Actions [top]
Conservation Actions: Since 1977, the Smooth-coated Otter has been listed on Appendix II of CITES. However, most range countries are not able to control the clandestine trade leading to extensive poaching. Nevertheless, it is a protected species in almost all the range countries which prohibits its killing.
The Smooth-coated Otter, once common in the wetlands and low lying areas of south Asia, is now restricted to a few protected areas. Creation of networks of Protected Areas, identification of sites as wetland of national and International importance under Ramsar Convention has to some extent halted the degradation of its habitat.
Over the years the IUCN SSC Otter Specialist Group has developed a cadre of biologist across Asia to conduct field surveys and has popularize otter conservation by promoting otters as ambassadors of the wetlands. However, concerted efforts to conserve this species are needed. For the long term survival of the species, policy based action, research on factors affecting its survival, habitat based action on creation and where required expansion of protected areas and communication and awareness building actions are needed.
Citation: de Silva, P., Khan, W.A., Kanchanasaka, B., Reza Lubis, I., Feeroz, M.M. & Al-Sheikhly, O.F. 2015. Lutrogale perspicillata. The IUCN Red List of Threatened Species 2015: e.T12427A21934884. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T12427A21934884.en. Downloaded on 11 August 2016.
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