Red List of South African Species

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Least Concern (LC)
Assessors: Bruce Mann Colin Buxton David Pollard Kent Carpenter
Facilitators: Claire Gorman
Reviewers: Mia Comeros-Raynal

Rationale

The Cape Stumpnose (Rhabdosargus holubi) is endemic to southern Africa and is known from St. Helena Bay, Western Cape to Maputo, Mozambique. It is estuarine-dependent as juveniles and adults typically inhabit shallow coastal waters over sandy and reefal areas. This species is taken in recreational and subsistence fisheries but there is no evidence of overfishing. The degradation of estuarine nursery areas along the southeastern seaboard of South Africa may have harmful impacts on Rhabdosargus holubi and could result in the reduction of biomass for this species. It is protected in several no-take MPAs. It is imperative that suitable marine and estuarine habitats be protected more effectively. It is listed as Least Concern.

Distribution

Rhabdosargus holubi is endemic to southern Africa and is known from St. Helena Bay, Western Cape to Maputo, Mozambique and occurs to 50 m depth (Fischer and Bianchi 1984, Smith and Heemstra 1986, van der Elst 1988, Whitfield 1998, Heemstra and Heemstra 2004). 

Population trend

Trend

Rhabdosargus holubi is one of the more abundant species found in South African estuaries (Wallace 1975a, Wallace et al. 1984, van der Elst 1988, Whitfield 1998). Fishery surveys showed an increase in catch per unit effort (CPUE) between 1975-1977 (0.008 fish/angler/day), 1994-1996 (0.024 fish/angler/day), and 2009-2010 (0.049 fish/angler/day) along the Kwazulu-Natal coast (Joubert 1981, Mann et al. 1997, Dunlop 2011). However, recent monitoring by shore patrols conducted along the KwaZulu-Natal coast show that CPUE of adult fish in the surf zone appears to be declining (NMLS unpublished data), but this may be partly due to misidentification with other Rhabdosargus spp. An increase in percent composition of R. holubi  in the overall recreational linefish catch was also observed between 1975-1977 (0.69%), 1994-1996 (2.03%), and 2009-2010 (4.94%) in Kwazulu-Natal (Joubert 1981, Mann et al. 1997, Dunlop 2011). CPUE of juveniles in estuaries on the Eastern Cape is highly variable, primarily due to variability of recruitment with no clear, long-term trends (James et al. 2008). Rhabdosargus holubi is currently the fifth most important shore angling species caught along the KwaZulu-Natal coast (Dunlop 2011). 


Threats

As Rhabdosargus holubi is an estuarine dependent species, the degradation of estuarine nursery areas along the entire southeastern seaboard may have resulted in an overall reduction in biomass of this species. Protection of suitable marine and estuarine habitats is therefore imperative for the future status of this species (Götz and Cowley 2012).

Uses and trade

Rhabdosargus holubi  is primarily caught by recreational and subsistence estuarine and marine shore fishers using light tackle (Mann and Beckley 2000).

Conservation

Rhabdosargus holubi has a daily bag limit of five fish per person per day and a minimum size limit of 20 cm TL for recreational and subsistence fishers and no commercial sale of this species is allowed (Department of Agriculture, Forestry and Fisheries 2012). Adults of this species are protected in a number of no-take MPAs over its entire distributional range including the De Hoop Marine Reserve, Goukamma, Tsitsikamma National Park, Sardinia Bay Reserve, Bird Island, Dwesa Cwebe and Pondoland (B. Mann and C. Buxton pers. comm. 2009). However, the important estuarine juvenile and sub-adult phase is in need of greater habitat protection as the number of EPAs are limited (Götz and Cowley 2012).

References 

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 author = {van der Elst, R.},
 publisher = {Struik Publishers},
 title = {A guide to the common sea fishes of Southern Africa (2nd edition)},
 year = {1988}
}
,@techreport{12137,
 author = {Mann, B.Q., Beckley, L.E. and R.P. van der Elst},
 institution = {Oceanographic Research Institute Unpublished Report 134},
 title = {Evaluation of linefishery participation and management along the KwaZulu-Natal coast},
 year = {1997}
}
,@techreport{12137,
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 title = {Marine Living Resources Act, 1998 (Act No. 18 of 1998) and relevant government gazettes and notices},
 year = {2012}
}
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 publisher = {South African Institute for Aquatic Biodiversity and National Inquiry Service Centre},
 title = {Coastal Fishes of southern Africa},
 year = {2004}
}
,@book{170164,
 author = {Fischer, W. and Bianchi, G.},
 title = {FAO species identification sheets for fishery purposes. Western Indian Ocean (Fishing Area 51)},
 year = {1984}
}
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 author = {van der Elst, R},
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 year = {1993}
}
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 pages = {1--16},
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 author = {Dunlop, M.I.},
 school = {University of KwaZulu- Natal, Durban, South Africa},
 title = {An assessment of the shore-based and offshore boat-based linefisheries of KwaZulu-Natal, South Africa},
 year = {2011}
}
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}
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}
,@techreport{170173,
 author = {Wallace, J.H.},
 institution = {Oceanographic Research Institute 41},
 title = {The estuarine fishes of the east coast of South Africa: III Reproduction},
 year = {1975}
}
,@article{170175,
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}
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}
,@techreport{170203,
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}
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}
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,@article{170203,
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}
,@book{170203,
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}
,@article{170203,
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 volume = {28},
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}
,]
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