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Austroglanis barnardi 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Siluriformes Austroglanididae

Scientific Name: Austroglanis barnardi (Skelton, 1981)
Common Name(s):
English Barnard's Rock-catfish, Spotted Rock Catfish
Synonym(s):
Gephyroglanis barnardi Skelton, 1981
Taxonomic Notes: Formerly placed in family Bagridae, but recognized in a separate family by Mo (1991) and de Pinna (1998) (Nelson 2006).

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(ii,iii,v)+2ab(ii,iii,v) ver 3.1
Year Published: 2017
Date Assessed: 2016-12-02
Assessor(s): Van der Walt, R., Swartz, E.R., Bills, R., Impson, D. & Jordaan, M.
Reviewer(s): Raimondo, D., Raghavan, R. & Freyhof, J.
Facilitator/Compiler(s): Van Der Colff, D.
Justification:
A range restricted species, known from three locations (Heks, Thee and Noordhoeks tributaries) in the Olifants-Doring River System (ODRS), South Africa. Its extent of occurrence (EOO) is 164 km2 and area of occupancy (AOO) is 36 km2. There is continuous decline in the number of mature individuals, AOO and quality of habitat due to predation from alien invasive fish and water abstraction. The species' habitat may also be threatened by pesticide runoff from the agricultural activities located next to the rivers. While it does not occur in any provincial nature reserves, all three tributaries are located within the Cederberg Mountain Catchment Area and the upper section of the Heks River is located within the Cederberg Wilderness Area. This species is listed as Endangered under criteria B1ab(ii,iii,v)+2ab(ii,iii,v).
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to three tributary streams of the Olifants branch of the Olifants-Doring River System (ODRS), Western Cape Province, South Africa. The ODRS drains the Cederberg and Koue Bokkeveld Mountains (Bills 1999). It has previously been recorded from the mainstream of the Olifants River at the Heks River confluence, but unsustainable water extraction has caused these areas to dry up several times in the last few years, suggesting that this area is recolonized from the Heks subpopulation.
Countries occurrence:
Native:
South Africa (Western Cape)
Additional data:
Estimated area of occupancy (AOO) - km2:36Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:164
Number of Locations:3
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Although the range of this species is reasonably well known, information about population trends is lacking. There has most likely been a loss of mainstream habitats in the last ten years, and the distribution range in the Noordhoeks tributary has fluctuated depending on where water extraction occurs. However, more accurate information is needed to study long-term trends. The last population estimate was done by Bills in 1999 and he estimated a total of 5020 individuals (Bills and Impson 2013).
Current Population Trend:Unknown
Additional data:
Number of mature individuals:5020Continuing decline of mature individuals:Yes
Population severely fragmented:Yes
No. of subpopulations:3

Habitat and Ecology [top]

Habitat and Ecology:Austroglanis barnardi occurs almost exclusively in shallow, cobble and riffle habitat in clear perennial rivers (Skelton 1981, Bills 1999). This habitat is comprised of layers of cobbles in fast flowing water. Water depths are typically less than 30 cm. This habitat is most common in tributary streams close to the confluence with the main Olifants River although it does also occur in upstream sections of tributary streams and in the mainstream Olifants River. The small body size of A. barnardi (Mhombeni, 2009) and the presence of short and slightly curved dorsal and pectoral fin spines would seem to be adaptations to moving between small crevices in this habitat.
Systems:Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):12

Use and Trade [top]

Use and Trade: All indigenous fish species of the Western Cape Province are listed as Endangered Wild Animals under Schedule 1 of the Provincial Nature Conservation Ordinance for the Western Cape, thereby preventing the collection and trade of the species without a permit. Translocation of indigenous freshwater fish species are controlled by CapeNature’s Indigenous Fish Utilisation policy (Jordaan et al. 2016).

Threats [top]

Major Threat(s): Alien invasive species have severely fragmented subpopulations of this species in the past. Smallmouth Bass (Micropterus dolomieu) and Spotted Bass (M. punctulatus) probably caused a major reduction in population size just after their introduction into the ODRS in the 1940s. The Noordhoeks and Thee Rivers are currently free of Micropterus spp. but are invaded by Banded Tilapia (Tilapia sparrmanii) (Mhombeni 2009, van der Walt et al. 2016). The third subpopulation is in the Hex River which is invaded by Smallmouth Bass and Bluegill Sunfish (Lepomis macrochirus). Here this species co-exists with these aforementioned alien fish species, but probably in reduced numbers because of predation. Unsustainable water extraction in summer is a major threat, especially the low gradient sections of tributary streams that this species seems to prefer. There is almost 100% abstraction from the lower reaches of the three tributary streams during the dry season (November to March), with the result that this species only survives above extraction points. The effect of agrichemicals, mainly insecticides, has not been quantified, but all the tributary streams have orchards planted alongside them and it is likely that insecticide runoff effects all three subpopulations (Bills 1999).

Conservation Actions [top]

Conservation Actions: Impson and Bills (2013) have developed a conservation plan for both Austroglanis species that occur in the ODRS. Impson et al. (2016) have produced a report on priority rivers in the ODRS for fish conservation, awareness and management purposes. Plans are underway to do river rehabilitation for other species in the Cederberg Mountains, and if successful it can be attempted for tributary streams where this species occurs. In 2013, an alien fish barrier was constructed above the Keerom road bridge that crosses the Noordhoeks River. This should prevent Micropterus spp. from invading the river above this point. An invasive population of Spotted Bass was successfully removed using mechanical methods from the Thee River between 2010 and 2014. Despite the headwaters of all three tributaries being within the Cederberg Mountain Catchment Area, the current distribution of A. barnardi is not within any provincial nature reserves.

Citation: Van der Walt, R., Swartz, E.R., Bills, R., Impson, D. & Jordaan, M. 2017. Austroglanis barnardi. The IUCN Red List of Threatened Species 2017: e.T2426A99448638. . Downloaded on 11 December 2017.
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