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Parachondrostoma toxostoma

Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_offStatus_vu_onStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII CYPRINIFORMES CYPRINIDAE

Scientific Name: Parachondrostoma toxostoma
Species Authority: (Vallot, 1837)
Common Name(s):
English South-west European Nase
Synonym(s):
Chondrostoma toxostoma (Vallot, 1837)

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2ce ver 3.1
Year Published: 2006
Date Assessed: 2006-01-31
Assessor(s): Crivelli, A.J.
Reviewer(s): Freyhof, J. & Darwall, W. (Mediterranean Workshop, Dec. 2004)
Justification:
The population of C. toxostoma is estimated to have declined by at least 30% in the past 10 years based on data from hybridisation studies (Crivelli, A. pers comm). It is threatened by hybridisation with C. nasus and by habitat destruction due to water extraction and pollution, and by dam construction.
History:
1996 Lower Risk/least concern (Baillie and Groombridge 1996)

Geographic Range [top]

Range Description: It is restricted to the Rhône river basin in France and Switzerland and to coastal rivers in France. In France it has been introduced in river basins of the Atlantic coast. It has also been recorded in the Aude and Herault (Kottelat, M. pers comm).
Countries:
Native:
France; Switzerland
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Decreasing.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: It prefers the lower reaches of rivers. It can be found also in reservoirs. In presence of Chondrostoma nasus (an introduced species), C. toxostoma occupies the areas upstream, and in the absence of C. nasus it occupies both upstream and downstream zones. Hybridization between C. nasus and C. toxostoma has been observed in the wild. Hybrids can successfully reproduce as shown by the introgressive capacity at the nuclear and mitochondrial level, and the survival of hybrids.
Systems: Freshwater

Threats [top]

Major Threat(s): Habitat destruction (dams) and introduction of Chondrostoma nasus. However the destruction of dams has also allowed C. nasus to extend its range further upstream. In the past it has been out competed in its range by introduced C. nasus. The disappearance of spawning sites is an important factor for the decline.

Conservation Actions [top]

Conservation Actions: It is listed in the Annex II of the European Union Habitats Directive and in Appendix III of the Bern Convention.

Citation: Crivelli, A.J. 2006. Parachondrostoma toxostoma. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 22 September 2014.
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