Red List of South African Species

Alternatively, Explore species
| National Red List categories | Partners |
Least Concern (LC)
Assessors: Stephanie Plön Vic Cockcroft
Contributors: Claire Relton Shanan Atkins
Reviewers: Matthew Child

Rationale

Although there are minor threats facing this species within the assessment region, we estimate a large overall population size with no observed decline. In the late 1980s, the population size was estimated at 15,000–20,000 and we suspect the population has remained stable over that time as no threats have intensified significantly for this offshore species. Thus, this species remains Least Concern. Ongoing molecular research should help to resolve its taxonomic status and this species should be reassessed once further data are available.

Regional population effects: This is a wide-ranging and common species globally (Hammond et al. 2008), and thus rescue effects are possible.

Distribution

Long-beaked Common Dolphins generally occur within 180 km of the coast. The global distribution of this species remains little known due to the current taxonomic confusion. In African waters the species has been reported from Gabon, Congo-Brazzaville, Angola and South Africa; additional reports of common dolphins from Namibia as well as Madagascar, Mozambique and Kenya could not be distinguished to species level (Best 2007).

In South African waters, the species is mainly found along the south coast between St. Helena Bay in the west and Richard’s Bay in the east, over the continental shelf within the 500 m isobaths (Findlay et al. 1992; Best 2007). However, the two extremes of the range may only be occupied seasonally (Samaai et al. 2005). The only records of Short-beaked Common Dolphins from the assessment region to date are either strandings (two from near Arniston on the south coast and one from the Cape Peninsula near Cape Town), or sightings far offshore in the southwest Indian Ocean (Samaai et al. 2005) or specimens from the west coast of South Africa (Cunha et al. 2015). Stomach content and parasite data indicate that D. capensis is found more inshore than D. delphis in the assessment region and this allopatric distribution may well result in the observed loss of genetic differentiation and taxonomic confusion (Best 2007).

Population trend

Trend

There are no estimates of global abundance for D. capensis and few local abundance estimates. A population of about 15,000–20,000 was estimated to occur off the south-east coast of South Africa between Port Elizabeth and Richards Bay in the late 1980s (Cockcroft & Peddemors 1990). We suspect the population has remained stable since then, but new population estimates are needed. Model-based estimates of generation time are 16.5 years (Taylor et al. 2007).

Threats

High organochlorine levels on the south-east coast, where agriculture is concentrated, may threaten the lives of first-born calves and may have deleterious impacts on the reproductive rates of the populations (Cockcroft 1999).

Since 2007 the incidental bycatch of Long-beaked Common Dolphins in bather protection nets off KwaZulu-Natal has declined dramatically, from 32 and 12 animals in 2005 and 2006, respectively, to an average of 2.85 dolphins between 2007 and 2014 (Port Elizabeth Museum unpubl. data). This can be largely attributed to a change in the administration of the nets and not a decline in local populations. However, Long-beaked Common Dolphins are known to be taken in gillnets, trawls, and purse seines in Indian Ocean waters. In addition, some common dolphins die annually in the South African purse-seine fishery for pelagic fish off the Western Cape (Best 2007). Although unfortunate, given the size of local populations it is assumed that these incidental mortalities in fishing gear are sustainable (Best 2007).

A significant portion of the diet is squid, especially for lactating females, as a water source (Young & Cockcroft 1994). There has been a decline in the inshore squid fishery, suggesting this may impact Long-beaked Common Dolphins.

Climate change might exacerbate a loss or shift in prey base, especially because of its clumped distribution pattern globally.

Uses and trade

There is direct take of this species in certain areas for human food, and as bait in fisheries, but this is not suspected to occur significantly or to be a threat within the assessment region.

Conservation

The species is listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Marine Living Resources Act (No. 18 of 1998). The shark nets of KwaZulu-Natal historically caught an annual average of 39 common dolphins, resulting in a total of 1,023 animals between 1980 and 2005 (Best 2007). However, since 2007 this trend has declined to an average of 2.85 dolphins per annum (Port Elizabeth Museum unpubl. data). The decrease in bycatch is most likely due to the removal of the shark nets during the winter sardine range expansion (the Sardine Run). This time-area closure strategy has thus proven to be an effective mitigation measure for this species.

Recommendations for managers and practitioners:
  • Systematic monitoring of the abundance and distribution of this species is recommended, particularly with reference to the winter sardine movements up the east coast.
Research priorities:
  • Molecular investigations of stock structure would assist in determining the impact of fishery interactions.
  • Taxonomic resolution. Taxonomic split in South African waters has not been resolved. There are possibly three different subspecies / species pooled into one.
  • Current population size and trend estimates.
Encouraged citizen actions:
  • Use information dispensed by the South African Sustainable Seafood Initiative to make good choices when buying fish in shops and restaurants (for example, wwfsa.mobi, FishMS 0794998795).
  • Buy fresh produce that has been grown in pesticide-free environments.
  • Save electricity and fuel to mitigate carbon dioxide emissions and hence rate of climate change.
  • Buy local products that have not been shipped.

References 

[@article{2060,
 author = {O’Donoghue, S.H., Whittington, P.A., Dyer, B.M. and Peddemors, V.},
 journal = {African Journal of Marine Science},
 pages = {361--374},
 title = {Abundance and distribution of avian and marine mammal predators of sardine observed during the 2005 KwaZulu-Natal sardine run survey},
 volume = {32},
 year = {2010}
}
,@book{2062,
 address = {Lawrence, Kansas},
 author = {Rice, D.W.},
 publisher = {Society for Marine Mammalogy, Special Publication Number 4},
 title = {Marine Mammals of the World: Systematics and Distribution},
 year = {1998}
}
,@inbook{2474,
 address = {San Diego, California, USA.},
 author = {Perrin  and Thewissen },
 booktitle = {Minke Whales <i>Balaenoptera acutorostrata</i> and <i>B. bonaerensis</i>},
 editor = {Perrin, W.F. and Brownell, R.L},
 pages = {750–754},
 publisher = {Academic Press},
 title = {Encyclopedia of Marine Mammals},
 year = {2002}
}
,@techreport{2475,
 address = {La Jolla, California},
 author = {Taylor, B.L., Chivers, S.J., Larese, J. and Perrin, W.F.},
 title = {Generation length and percent mature estimates for IUCN assessments of cetaceans},
 year = {2007}
}
,@book{2476,
 address = {Cape Town, South Africa},
 author = {Best, P.B.},
 publisher = {Cambridge University Press},
 title = {Whales and Dolphins of the Southern African Subregion},
 year = {2007}
}
,@article{2762,
 author = {Cockcroft VG, De Kock AC, Ross GJB, Lord DA.},
 journal = {South African Journal of Zoology},
 pages = {144--148},
 title = {Organochlorines in common dolphins caught in shark nets during the Natal “sardine run".},
 volume = {25},
 year = {1990}
}
,@article{2762,
 author = {Findlay KP, Best PB, Ross GJB, Cockcroft VG.},
 journal = {South African Journal of Marine Science},
 pages = {237–270},
 title = {The distribution of small odontocete cetaceans off the coasts of South Africa and Namibia},
 volume = {12},
 year = {1992}
}
,@article{6337,
 author = {Jefferson, T. A. and Van Waerebeek, K.},
 journal = {Marine Mammal Science},
 number = {4},
 pages = {787--818},
 title = {The taxonomic status of the nominal dolphin species <i>Delphinus tropicalis</i> van Bree, 1971},
 volume = {18},
 year = {2002}
}
,@article{6337,
 author = {Van Bree, P. J. H. and Gallagher, M. D.},
 journal = {Beaufortia},
 pages = {1--8},
 title = {On the taxonomic status of <i>Delphinus tropicalis</i> van Bree, 1971 (Notes on Cetacea, Delphinoidea IX)},
 volume = {28},
 year = {1978}
}
,@electronic{6337,
 address = {www.iucnredlist.org},
 author = {Hammond, P. S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W. F., Scott, M. D., Wang, J. Y., Wells, R. S., and Wilson, B. },
 title = {<i>Delphinus capensis</i>. In 'The IUCN Red List of Threatened Species'. Version 2013.1},
 year = {2008}
}
,@article{6337,
 author = {Natoli, A., Canadas, A., Peddemors, V. M., Aguilar, A., Vaquero, C., Fernandez-Piqueras, P., and Hoelzel, A. R. },
 journal = {Journal of Evolutionary Biology},
 pages = {943--954},
 title = {Phylogeography and alpha taxonomy of the common dolphin (<i>Delphinus</i> sp.)},
 volume = {19},
 year = {2006}
}
,@article{6337,
 author = {Gui, D., L. Karczmarski, R.-Q. Yu, S. Plön, L. Chen, Q. Tu, G. Cliff and Y. Wu},
 journal = {Environmental Science and Technology},
 number = {7},
 pages = {4008--4017},
 title = {Profiling and Spatial Variation Analysis of Persistent Organic Pollutants in South African Delphinids},
 volume = {50},
 year = {2016}
}
,@article{6337,
 author = {Ambrose ST, Froneman PW, Smale MJ, Cliff G, Plön S.},
 journal = {Marine biology},
 pages = {1543--1561},
 title = {Winter diet shift of long-beaked common dolphins (<i>Delphinus capensis</i>) feeding in the sardine run off KwaZulu-Natal, South Africa.},
 volume = {160},
 year = {2013}
}
,@article{6337,
 author = {Cockcroft VG.},
 journal = {Journal of Cetacean Research and Management, Special Issue},
 pages = {169--176},
 title = {Organochlorine levels in cetaceans from South Africa: a review.},
 volume = {1},
 year = {1999}
}
,@article{6337,
 author = {Cockcroft VG, Peddemors VM.},
 journal = {South African Journal of Marine Science},
 pages = {371--377},
 title = {Seasonal distribution and density of common dolphins <i>Delphinus delphis</i> off the south-east coast of southern Africa},
 volume = {9},
 year = {1990}
}
,@article{6337,
 author = {Connell AD.},
 journal = {African Journal of Marine Science},
 pages = {331--336},
 title = {A 21-year ichthyoplankton collection confirms sardine spawning in KwaZulu-Natal waters},
 volume = {32},
 year = {2010}
}
,@article{6337,
 author = {Cunha, H.A., de Castro, R.L., Secchi, E.R., Crespo, E.A., Lailson-Brito, J., Azevedo, A.F., Lazoski, C. and Solé-Cava, A.M.},
 journal = {PloS One},
 number = {10},
 pages = {e0140251},
 title = {Molecular and morphological differentiation of common dolphins (<i>Delphinus</i> spp.) in the southwestern Atlantic: testing the two species hypothesis in sympatry},
 year = {2015}
}
,@electronic{6337,
 author = {IUCN (International Union for Conservation of Nature).},
 publisher = {The IUCN Red List of Threatened Species. Version 3.1. http://www.iucnredlist.org},
 title = {<i>Delphinus capensis</i>},
 year = {2008}
}
,@article{6337,
 author = {O’Donoghue SH, Drapeau L, Dudley SF, Peddemors VM.},
 journal = {African Journal of Marine Science},
 pages = {293--307},
 title = {The KwaZulu-Natal sardine run: shoal distribution in relation to nearshore environmental conditions, 1997–2007},
 volume = {32},
 year = {2010}
}
,@article{6337,
 author = {Rosel, P.E., Dizon, A.E. and Heyning, J.E.},
 journal = {Marine Biology},
 pages = {159--167},
 title = {Genetic analysis of sympatric morphotypes of common dolphins (genus <i>Delphinus</i>)},
 volume = {119},
 year = {1994}
}
,@article{6337,
 author = {Samaai, T., Best, P.B. and Gibbons, M.J.},
 journal = {African Journal of Marine Science},
 pages = {449--458},
 title = {The taxonomic status of common dolphins <i>Delphinus</i> spp. in South African waters},
 volume = {27},
 year = {2005}
}
,@article{6337,
 author = {Wells RS, Rhinehart HL, Hansen LJ, Sweeney JC, Townsend FI, Stone R, Casper DR, Scott MD, Hohn AA, Rowles TK.},
 journal = {EcoHealth},
 pages = {246--254},
 title = {Bottlenose dolphins as marine ecosystem sentinels: developing a health monitoring system},
 volume = {1},
 year = {2004}
}
,@article{6337,
 author = {Young DD, Cockcroft VG.},
 journal = {Journal of Zoology},
 pages = {41--53},
 title = {Diet of common dolphins (<i>Delphinus delphis</i>) off the south-east coast of southern Africa: opportunism or specialization?},
 volume = {234},
 year = {1994}
}
,]
Send feedback about this assessment to SANBI

Lead agencies, Partners and Funders

See the partners page