Rheocles vatosoa 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Atheriniformes Bedotiidae

Scientific Name: Rheocles vatosoa Stiassny, Rodriguez & Loiselle, 2002

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(i,ii,iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2016-06-23
Assessor(s): Ravelomanana, T. & Sparks, J.S.
Reviewer(s): Randrianizahaisa, H., Rasoloariniaina, R & Velosoa, J.
Contributor(s): Loiselle, P.V.
Facilitator/Compiler(s): Darwall, W.R.T.
A recently described species known from the Lokoho and Andapa river basins, Madagascar. Even though the catchment of the streams in the Lokoho basin is protected by the Marojejy and Anjanaharibe Sud National Parks,  the restricted range (EOO less than 5,000 km²), single location (based on the threat from invasive alien species), and a continued decline in habitat extent and quality outside the National Park (mainly due to deforestation and rice farming), lead to an assessment of Endangered for this species.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The type series and all available specimens of Rheocles vatosoa have been collected in upper reaches of the Lokoho River in the general vicinity of the town of Andapa (Stiassny et al. 2002).
Countries occurrence:
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:550
Continuing decline in extent of occurrence (EOO):Yes
Number of Locations:1
Lower elevation limit (metres):157
Upper elevation limit (metres):940
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:In forested streams within portions of its range, this species is still abundant. Within the Andapa basin and in Andrakata River, this speces is now very rare.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes

Habitat and Ecology [top]

Habitat and Ecology:Throughout its range, Rheocles vatosoa is found predominately in clear streams over gravel or coarse sand bottoms. Such streams are characterized by soft, slightly acidic to moderately alkaline water, total and carbonate hardness value < 1°DH, electrical conductivity between 23 and 30µS/cm and pH values between 6.8 and 7.5.
Continuing decline in area, extent and/or quality of habitat:Yes
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: Fishery activity using mosquito net is common in the Andapa rice fields. During the time period of our observations, this species was completely extirpated from this area (Ravelomanana, pers. obs.)

Threats [top]

Major Threat(s): Ongoing deforestation, mosquito net fishery activity  and the presence of the exotic species: Gambusia holbrooki, Xiphophorus hellerii and Channa maculata pose the principal threats to the long-term survival of R. vatosoa. The central part of the species range has also been converted into extensive areas of rice fields where this species is no longer present.

Conservation Actions [top]

Conservation Actions: This species occurs in Anjanaharibe Sud and Marojejy protected areas.

Citation: Ravelomanana, T. & Sparks, J.S. 2016. Rheocles vatosoa. The IUCN Red List of Threatened Species 2016: e.T44660A58309149. . Downloaded on 21 September 2018.
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