SANBI

Rationale

Janbruin (Gymnocrotaphus curvidens) is a South African endemic that inhabits shallow reef areas. This species is primarily caught by spearfishers and shore anglers. Information about biology and stock status of G. curvidens is extremely limited and further study is required. This species is prohibited for sale by commercial fishers and a daily bag limit of five fish per person per day is in place for recreational and subsistence fishers. The range of G. curvidens overlaps with a number of marine protected areas. No major threats to this species have been identified. It is therefore listed as Least Concern.

Distribution

Gymnocrotaphus curvidens is endemic to South Africa, from False Bay to Port St. Johns (Heemstra and Heemstra 2004). This species has been occasionally observed in underwater visual census surveys from False Bay to Bashee River (C. Buxton and B. Mann pers. comm. 2009). Gymnocrotaphus curvidens usually occurs in shallow waters but is known to occur to depths of 80 m (Buxton and Smale 1984, Smale and Buxton 1989, van der Elst 1993, Heemstra and Heemstra 2004).

Habitat View more ecological information

Population trend

Trend

Gymnocrotaphus curvidens was commonly seen in a survey of shallow water reef fish in Algoa Bay and the Tsitsikamma National Park (Smale and Buxton 1985, Beckley and Buxton 1989). It is rare for two individuals of this species to be caught in one spot (Smith and Heemstra 1986). A stock assessment has not been conducted for G. curvidens. Similarly little is known of trends in catch per unit effort, catch composition, mean size, and sex ratio of this species (Wood and Cowley 2012).

Threats

Currently, no major threats have been identified for G. curvidens.

Uses and trade

Gymnocrotaphus curvidens is mainly taken by spearfishers diving in shallow to moderate depths of 5 to 20 m and is occasionally taken by shore anglers (Clarke and Buxton 1989, Wood and Cowley 2012). This species is rarely taken by recreational ski-boat anglers (Smale and Buxton 1985, Wood and Cowley 2012).

Conservation

Current regulations in place for G curvidens include a recreational and subsistence daily bag limit of five fish per person per day and sale is prohibited by commercial fishers (Department of Agriculture, Forestry and Fisheries 2012). This species is effectively 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 and Dwesa Cwebe (B. Mann and C. Buxton pers. comm. 2009). The implementation of a minimum landing size of 30 cm TL is recommended as a precautionary measure (Wood and Cowley 2012).

References

[@techreport{12137,
 address = {Staatskoerant},
 author = {Department of Agriculture, Forestry and Fisheries},
 title = {Marine Living Resources Act, 1998 (Act No. 18 of 1998) and relevant government gazettes and notices},
 year = {2012}
}
,@book{170160,
 address = {Grahamstown, South Africa},
 author = {Heemstra, P.C. and Heemstra, E.},
 publisher = {South African Institute for Aquatic Biodiversity and National Inquiry Service Centre},
 title = {Coastal Fishes of southern Africa},
 year = {2004}
}
,@book{170169,
 address = {Cape Town, South Africa},
 author = {van der Elst, R},
 publisher = {Struik Publishers},
 title = {A guide to the common sea fishes of southern Africa},
 year = {1993}
}
,@article{170169,
 author = {Clarke, J.R. and Buxton, C.D.},
 journal = {South African Journal of Marine Science},
 pages = {183--194},
 title = {A survey of the recreational rock angling fishery at Port Elizabeth, on the east coast of South Africa},
 volume = {8},
 year = {1989}
}
,@article{170170,
 author = {Smale, M.J. and Buxton, C.D.},
 journal = {South African Journal of Marine Science},
 pages = {131--144},
 title = {Aspects of the recreational ski boat fishery off the Eastern Cape},
 volume = {3},
 year = {1985}
}
,@article{170170,
 author = {Buxton, C.D.  and Smale, M.J.},
 journal = {Koedoe},
 number = {1984},
 pages = {13--24},
 title = {A preliminary investigation of the ichthyofauna of the Tsitsikamma Coastal National Park},
 volume = {27},
 year = {1984}
}
,@techreport{170170,
 author = {SAUFF},
 title = {South African Underwater Fishing Federation},
 year = {2012}
}
,@book{170173,
 address = {Grahamstown},
 author = {Smith, M.M. and Heemstra, P.C},
 publisher = {Springer-Verlag},
 title = {Smith's Sea Fishes},
 year = {1986}
}
,@article{170175,
 author = {Smale, M.J. and Buxton, C.D.},
 journal = {South African Journal of Zoology},
 pages = {58 67},
 title = {The subtidal gully fish community of the Eastern Cape and the role of this habitat as a nursery area},
 volume = {24},
 year = {1989}
}
,@article{170185,
 author = {Beckley, L.E. and Buxton, C.D.},
 journal = {Transactions of the Royal Society of Southern Africa},
 pages = {29 38},
 title = {Underwater observations of reef fish in and around Algoa Bay, South Africa},
 volume = {47},
 year = {1989}
}
,@inbook{170193,
 address = {Durban},
 author = {},
 booktitle = {<i>Gymnocrotaphus curvidens</i>},
 editor = {Wood, A.D. and Cowley, P.D.},
 pages = {235--236},
 publisher = {Oceanogrpahic Research Institute},
 title = {Southern African Marine Linefish Species profiles},
 year = {2012}
}
,]

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Red List of South African Species