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Description |
Geographic Range [top]
Range Description: It is widely known from the Ganges-Brahmaputra systems (India (Uttar Pradesh, Assam, Manipur, Madhya Pradesh, Bihar, West Bengal and Arunachal Pradesh), and from Myanmar, Thailand, Laos, Cambodia, Indonesia (Java), Malaysia and Nepal. It should also be looked for in Bangladesh.
This species is widely distributed across southeast Asia from the Ganges region in India to the island of Sumatra (Kohler and Glaubrecht 2001). The occurrence of this species is conceived to range from North East India (Ganges, Assam, Manipur, Meghalaya, Mizoram, Skiim, West-Bengal), Bangladesh, Burma, Thailand, Cambodia and Viet Nam to the Malaysian Peninsula (abundant in the Pahang River system) and Sumatra. It has been reported from the Mekong where it is the only cerithiodean species found (Brandt 1974: Davis 1982 in Kohler and Glaubrect 2001).
Kohler and Glaubrect (2001) found specimens from museum collections confirming that this species is found in lakes on Sumatra, such as Lake Toba, Lake Maninjau, Lake Singkarah, and Lake Ranau.
Kohler and Glaubrect (2001) considered reports from Sri Lanka (Annandale, 1920), Java (Rensch, 1934; Benthem Jutting, 1956) and Borneo (Brandt 1974) as dubious due to confusion with other species.
More research or clarification is needed on the area of Bangladesh that this species is distributed, as there are 230 small and large rivers in Bangladesh (Reuters 2009).
Countries occurrence:
Native:
Cambodia; India (Arunachal Pradesh, Assam, Bihar, Madhya Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Uttar Pradesh, West Bengal); Indonesia (Sumatera); Lao Peoples Democratic Republic; Malaysia (Peninsular Malaysia); Myanmar (Myanmar (mainland)); Nepal; Thailand; Viet Nam
Range Map: Click here to open the map viewer and explore range.
Population [top]
Population:
There is no information on the population and its trends for this species, but survey data suggests that it is relatively widespread and common.
Current Population Trend: Unknown
Additional data:
?Population severely fragmented: No
Habitat and Ecology [top]
Habitat and Ecology: It is found in moderately fast running streams and rivers with rich invertebrate diversity (P. Budha pers. comm. 2010).
This species is a eurytopic species, occurring in habitats ranging from clear, narrowly tangled jungle creeks, comprising of sandy bottoms, to large muddy rivers (Abbott, 1948, Davis 1971 in Kohler and Glaubrect 2001). This species lives on rocks, mud, sand and root systems, often among leaf litter in the water column (Kohler and Glaubrect 2001).
There have been reports implying a preference for this species; Davis (1971) found this species in quiet, marginal waters in comparison to the spiny forms of this genus that are found among rocks in rapids (Kohler and Glaubrect 2001), Subba Rao (1989) states that this species lives in ponds and does not occupy swift streams. And according to Krautrachue, Upatham, Vichasri and Baidikul (1990) the species inhabits mainly streams and rivers, only rarely still waters (Kohler and Glaubrect 2001).
Recent samplings by the Kohler were taken in Lake Toba, clear streams and muddy irrigation channels of rice fields on Sumatra (Kohler and Glaubrect 2001).
Systems: Freshwater
Use and Trade [top]
Use and Trade: It is taken as food by people in India (Subba Rao 1989) and some ethnic groups particularly Tharu, Mushar, Danuwar in Nepal (Budha pers. obs. 2010). B. costula is also used as food in Arunachal Pradesh, Manipur, Meghalaya and North Bengal (Ramakrishna and Dey 2007).
This species is also an edible, market species, research has also shown this species to have accumulations of As (Arsenic), Cu (Copper), Fe (Iron), Se (Selenium) and Zn (Zinc) in individual specimens tissues (Lau et al., 1998).This species is also listed as a consumed species in the regions of North and West Bengal (FAO 1989).
Threats [top]
Major Threat(s): Major threats occur to part of the species range, but as there is not a complete range for this species, there may be further threats to this species.
The Ganges River, India is extremely polluted from increase in human population, sewage discharge, and industrial action (Sinha and Das 1993). Other areas of India (such as Assam) are heavy tea producers - however whether this causes a direct threat needs further research.
Bangladesh rivers, and in particular the Buriganga river, are threatened by pollution, encroachment, tannery discharge, and chemical discharge from cadmium, chromium and mercury (Reuters 2009). Some portions of most rivers, particularly when located near urban and industrial areas, are highly polluted, due to untreated industrial effluents and the continuing dumping of raw sewage (Nishat, A. pers. comm. 2009). The most polluted reach of the Buriganga is the area of Dhaka City, during the dry season the dissolve oxygen content goes down to almost zero (Nishat, A. pers. comm. 2009). The Buriganga is considered to be biologically dead, and the rivers of the Sitalakhya, Turag and Balu also receive a high influx of waste water therefore with the potential to be as polluted as the Buriganga (Reuters 2009). A large number of small rivers as well as wetlands located near small towns also become highly polluted (Nishat, A. pers. comm. 2009). Other polluted areas within Bangladesh are the Sitalakhya in Narayanganj; the Rupsha in Khulna, and the Karnafuli in Chittagong (Nishat, A. pers. comm. 2009).
The distribution of this species in Myanmar is under threat from unregulated pollution and habitat degradation, as there is no up-to-date laws for the regulation of pollution, and there is an increasing pressure on farmers to double and treble rice crops, which has lead to massive deforestation (Gutter 2001). Additionally, there is a lack of crop rotation, damaged water supply, and the use of fertilizers is leading to soil depletion and pestilence (Gutter 2001). There are further threats from large hydroelectric projects on Myanmars rivers, and rapidly expanding industries such as mining, oil and gas (Gutter 2001).
In 2005, Malaysia declared a pollution emergency, which was predominantly air pollution, however more research is needed into the levels of water pollution and other threats to this species within Malaysia (abc online, 2005).
Conservation Actions [top]
Conservation Actions:
More information is needed on the impact of pollution and other threats on the species.
Citation: Budha, P.B., Dutta, J. & Daniel, B.A. 2010. Brotia costula. The IUCN Red List of Threatened Species 2010: e.T166776A6280867. http://dx.doi.org/10.2305/IUCN.UK.2010-4.RLTS.T166776A6280867.en. Downloaded on 04 February 2016.
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