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Bedotia madagascariensis 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Atheriniformes Bedotiidae

Scientific Name: Bedotia madagascariensis
Species Authority: Regan, 1903
Common Name(s):
English Zona

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2016-06-22
Assessor(s): Ravelomanana, T. & Sparks, J.S.
Reviewer(s): Raminosoa, N., Randrianizahaisa, H., Rasoloariniaina, R & Velosoa, J.
Contributor(s): Loiselle, P.V. & Participants of the CBSG/ANGAP CAMP "Faune de Madagascar" workshop, Mantasoa, Madagascar 2001
Facilitator/Compiler(s): Darwall, W.R.T.
Justification:
Assessed as Endangered, the Extent of Occurrence is less than 5000 km².  Even if it is known from a number of Madagascar's east coast rivers and lakes, in the region between Ivoloina and Mangoro, the habitat is fragmented and continues to be heavily impacted by siltation and flow changes due to deforestation. The impact of introduced species like Channa maculata and the use of mosquito nets as seine nets have a huge impact on local populations. All the coastal rivers in this area are hydrologically connected by the Pangalana canal. As a key threat is the invasive Channa maculata it is restricted to a single location.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to Madagascar. The present range of Bedotia madagascariensis extends from the lower reaches of the Ivoloina River, the effective northern terminus of the Lakandrano Pangalana, at least as far south as Manambolo Creek, which drains into the Lakandrano Pangalana 10 km south of the town of Vatomandry (Loiselle and Rodriguez 2007).
Countries occurrence:
Native:
Madagascar
Additional data:
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is abundant in Pangalana canal and in lower reaches of many streams joining the Pangalana.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes

Habitat and Ecology [top]

Habitat and Ecology:According to Loiselle and Rodriguez (2007), Bedotia madagascariensis inhabits clear streams flowing under partial or complete forest cover at altitudes up to 30 meters above sea level. As long as the stream is shaded, this species appears indifferent to the composition of the riparian vegetation, prospering even when it is comprised entirely of exotic species. Although capable of breasting a fairly strong current, B. madagascariensis prefers the quieter sections of well-shaded streams. Rivers draining the eastern versant of Madagascar are characterised by extremely soft water (General hardness [GH]:< 17.1 ppm, electrical conductivity 17.0–27.0 ìmho/cm2). It is thus not unusual to find this species inhabiting classic black water habitats such as Dracaena/Pandanus swamps, where pH values can be as low as 4.8. Although salinity levels up to 5.0 parts per thousand are tolerated in captivity. Water temperatures measured during the month of October in the habitats it frequents ranged from 23°-32°C.
Systems:Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: Bedotia madagascariensis is harvested by local people for local consumption.

Threats [top]

Major Threat(s): The main threat to the species is habitat loss and degradation through siltation caused by deforestation. According to Loiselle and Rodriguez (2007), prior to the introduction in the early 1970's of the spotted snakehead, Channa maculata, the only fish large enough to prey upon B. madagascariensis were cichlids of the genus Paratilapia, flagtails of the genus Kuhlia, the endemic grunter Mesopristes elongatus, Glossogobius giuris, and eels of the genus Anguilla. This species is also vulnerable to piscivorous wading birds and the Malagasy malachite kingfisher, Corythornis vintsioides. Despite its relatively small size, there is an active artisanal fishery for B. madagascariensis over most of its range. In captivity, individuals of this species can live for up to ten years. Predation pressure in all probability precludes comparable longevity in nature.

Conservation Actions [top]

Conservation Actions: Vohibola forest is the only protected area where Bedotia madagascariensis was found.

Citation: Ravelomanana, T. & Sparks, J.S. 2016. Bedotia madagascariensis. The IUCN Red List of Threatened Species 2016: e.T2721A58294066. . Downloaded on 10 December 2016.
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