Hobbseus valleculus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Cambaridae

Scientific Name: Hobbseus valleculus (Fitzpatrick, 1967)
Common Name(s):
English Choctaw Riverlet Crayfish

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii) ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor(s): Adams, S., Cordeiro, J. & Jones, R.L.
Reviewer(s): Collen, B. & Richman, N.
Contributor(s): Livingston, F., Livingston, F., Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G.
Hobbseus valleculus has been assessed as Endangered under criterion B1ab(iii). This species has an estimated extent of occurrence of 2,450 km² and is present in just four known sites. At present there is a decline in the quality of this species habitat as a result of agricultural run-off and siltation, with further siltation and habitat degradation expected with the construction of a transmission line. Further research on the distribution and population trends of this species is needed to better determine how much of the population is being affected by threats, and whether it faces imminent threat of extinction.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is restricted to the upper Pearl River watershed, from a few localities in Attala, Choctaw, and Kemper counties, Mississippi, USA (Fetzner 2008, R.L. Jones pers. comm. 2010)). In addition, this species has been collected from the upper headwaters of the Noxubee River (Tombigbee River drainage) in Winston County, Mississippi (R.L. Jones pers. comm. 2010). The latter locality is approximately 4.6 km northeast of the Pearl River locality record. The records from the Noxubee drainage are clustered in an area of less than two square kilometres (R.L. Jones pers. comm. 2010). This species' presence in Webster County, although a neighbouring county, is uncertain as no voucher specimens exist to support this part of the range. Kemper County lies within the Tombigbee drainage but is still regarded as possibly containing specimens of this species (S. Adams pers. comm. 2009). This species is currently only known from four collection localities (Adams 2008). The extent of occurrence of this species has been estimated at approximately 2,450 km².
Countries occurrence:
United States (Mississippi)
Additional data:
Number of Locations:4
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:This species is not common and is not particularly well known in collections, having last been collected in 2002 (S. Adams, pers. comm. 2009). It must be noted that the last collection was not to be taken literally as most surveys focus on stream habitat rather than ditches and ponds (S. Adams, pers. comm. 2009), although current information suggests that this species is rare.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:Unknown

Habitat and Ecology [top]

Habitat and Ecology:This species inhabits small, permanent streams comprising of sand, silt and gravel beds (Fitzpatrick 1967). Typically the water flow in these habitats is between sluggish and moderately flowing with emergent vegetation (Fitzpatrick 1967). There are, however, not many gravel bed habitats in Mississippi, mainly due to the  geology of the area (S. Adams, pers. comm. 2009). This species has additionally been collected from narrow headwater streams (some less than 1 m in width), ephemeral ponds and in roadside ditches (R.L. Jones pers. comm. 2010).

Threats [top]

Major Threat(s): This species is threatened by siltation and agricultural run-off (Fitzpatrick 1967). In addition, in Choctaw County a transmission line route is being constructed (TVA 2006). During a survey, this species was identified as either within the right-of-way or immediately downstream from the construction site (TVA 2006). This will cause disturbance and increased siltation of the streams in this area (TVA 2006). Previous to this, Fitzpatrick (1996) stated this species did not seem to be imminently threatened.

Conservation Actions [top]

Conservation Actions: This species has been given a Global Heritage Rank Status of G1 by NatureServe (Taylor et al. 2007, NatureServe 2009) and assessed as 'threatened' by the American Fisheries Society (Taylor et al. 2007). Both the Pearl River and Noxubee localities of this species are within the Tombigbee National Forest (R.L. Jones pers. comm. 2010), and may thus be given some protection under the area's conservation remit. 

Further research is needed on the population trends and distribution of this species.

Citation: Adams, S., Cordeiro, J. & Jones, R.L. 2010. Hobbseus valleculus. The IUCN Red List of Threatened Species 2010: e.T10209A3182132. . Downloaded on 18 June 2018.
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