|Scientific Name:||Enhydris enhydris|
|Species Authority:||(Schneider, 1799)|
Homalopsis enhydris (Schneider, 1799)
Hydrus enhydris Schneider, 1799
Hypsirhina enhydris (Schneider, 1799)
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Murphy, J., Brooks, S.E., de Silva, A. & Khan, S.E.|
|Reviewer/s:||Livingstone, S.R., Elfes, C.T., Polidoro, B.A. & Carpenter, K.E. (Global Marine Species Assessment Coordinating Team)|
This species is extremely abundant throughout its extensive range and it occurs in a wide range of habitats, including man-made. Although it is harvested for crocodile and human food, this threat seems to be localized to Cambodia. This species adapts extremely well to human interference, particularly fished areas. This species is listed as Least Concern.
|Range Description:||This widespread species ranges from Nepal, northeast peninsular India and an apparent isolated subpopulation in Sri Lanka, eastwards throughout Bangladesh and Myanmar, across the Indochinese Peninsula, and southwards into Indonesia from Sumatra to Sulawesi (Murphy 2007).|
Native:Bangladesh; Cambodia; India; Indonesia (Jawa, Kalimantan, Sulawesi, Sumatera); Malaysia (Peninsular Malaysia, Sarawak); Myanmar; Nepal; Singapore; Sri Lanka; Thailand; Viet Nam
|Range Map:||Click here to open the map viewer and explore range.|
This species is very abundant in shallow open wetlands with submergent-emergent vegetation (Murphy 2007).
Some localities have dense populations of this snake (Lake Songhkla, Thailand; Kabin Buri, Thailand; Tonlé Sap, Cambodia), these are lowland locations that have become freshwater habitats relatively recently. Lake Songhkla was an ocean bay 200 years ago and it undergoes salt water intrusions and is heavily fished.
In Lake Songkhla (1996-1999), pit tags were put in 235 snakes, with 144 recaptures. As a result it is estimated that the population size at this study site is 406-567 snakes. A linear estimate of one snake per two metres of shoreline (Murphy 2007).
In the artificial lake behind Koshi Dam (Nepal) this species can be found in "great numbers" (Schleich and Kästle 2002). Daniel (2002) describes the snake as uncommon in India.
|Habitat and Ecology:||
This species uses a variety of stagnant and slow moving aquatic habitats ranging from rice paddies, canals and ditches to lakes and rivers. It uses relatively shallow fresh water environments with muddy substrata and can be found in and around urban areas. It appears to thrive in disturbed habitats. This species is very intolerant of salt water. Neonates are found in the mud-root tangle near water (Murphy 2007).
This species feeds almost exclusively on fish (Murphy 2007), but in lean periods it may also prey on lizards and frogs (Sharma 2003).
There are two breeding seasons per year, though it is not known if females will reproduce during both seasons (S. Brooks pers. comm.).
Following a decline in fish stocks in Tonlé Sap Lake, Cambodia, intensive harvesting of various watersnakes began in 1997 (Stuart et al. 2000). This species is heavily exploited in Tonlé Sap Lake in Cambodia, and populations are declining in this particular area (Brooks et al. 2007). They make up approximately 70% of the catch. They are used primarily for crocodile food but are also sold for human consumption. Its eggs are usually sold separately as an expensive delicacy.
Other localities where it occurs are disturbed habitats, heavily impacted by the fishing industry and other human activities. It appears that E. enhydris may be a disturbed habitat/early successional stage specialist. It is entirely possible that as aquatic ecosystems mature, these populations will undergo natural declines and stabilize at a much lower level (JCMnaturalhistory.com).
|Conservation Actions:||There are no conservation measures for this species, however, in places its distribution coincides with protected areas, probably providing small safeguards. Further research and monitoring is needed on its harvest levels and population trends, to ensure declines do not increase.|
|Citation:||Murphy, J., Brooks, S.E., de Silva, A. & Khan, S.E. 2010. Enhydris enhydris. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 15 March 2014.|
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