Red List of South African Species

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Least Concern (LC)
Assessors: Stephanie Plön Vic Cockcroft
Contributors: Fiona Preston-Whyte Claire Relton Shanan Atkins Ken Findlay Mike Meyer Herman Oosthuizen Simon Elwen
Reviewers: Matthew Child

Rationale

This species is listed as Least Concern, due to the suspected distribution pattern of the species as far offshore, its rarity in the assessment region, and the perceived lack of major threats that could cause rapid decline. The cost-benefit ratio makes research unlikely and places the Pygmy Killer Whale low on the list of conservation priorities. Despite this classification, the potential pressures that threaten most cetacean species, such as high intensity sound pollution and bycatch in fisheries, are likely to be increasing in South African waters. Such threats should be monitored for their impacts on this species.

Regional population effects: Pygmy Killer Whales are thought to occur seasonally in South African waters (Findlay 1989), and although their movement patterns are largely unknown, no barriers to dispersal are recognised, thus rescue effects are possible.

Distribution

This is a tropical, subtropical, and possibly warm-temperate species that inhabits the pelagic waters, of all major oceans, found mainly off the continental shelf. Pygmy Killer Whales are known to migrate into warmer waters due to physiological requirements (Caldwell & Caldwell 1971). The distribution of this species has been mapped mainly from strandings and skulls, sited internationally around Japan, the Hawaiin Islands, the Caribbean Sea and Senegal. The Southern African distribution is known from Kosi Bay to the Orange River with sightings around Richards Bay (Bass 1968; Best 1970), Durban, Cape Town and Lüderitz (Best 1970; Caldwell & Caldwell 1971).

Population trend

Trend

This species is considered naturally rare and, based on the few existing datasets, occurs at much lower densities compared to other cetaceans (Jeyabaskaran et al. 2011). No global, and very few regional, population estimates of abundance exist (Jeyabaskaran et al. 2011), and none are available for the assessment region. A very low frequency of Pygmy Killer Whale strandings have been documented in South Africa, and similarly, sightings records are extremely uncommon. In August 1969, 11 individuals were sighted off KwaZulu-Natal in waters between 1,000–2,000 m deep (Findlay et al. 1992).

Threats

Due to the predicted small population size of Pygmy Killer Whales within the assessment region, it is likely that minor localised threats, could have a substantial influence on population stability. In general, loss of prey base due to anthropogenic overfishing, impacts of climate change, and the subsequent ecosystem changes have the potential to affect Pygmy Killer Whales.

Although this species, like beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration, it is not considered more vulnerable than other cetaceans. There are no known reports of Pygmy Killer Whale bycatch in trawls or long-lines in South African fisheries, and hence no significant bycatch is suspected. However, they have been killed incidentally in various types of fishing gear in many other areas of the species’ range (Jeyabaskaran et al. 2011).

Climate change is expected to have both direct and indirect effects on prey species, which will indirectly affect the distribution, migration, population structure and reproductive success of cetacean species, and additionally may enhance their vulnerability to disease, anthropogenic marine pollution and contaminants (Learmonth et al. 2006).

Uses and trade

This species is not utilised or traded within the assessment region.

Conservation

The Pygmy Killer Whale is listed in Appendix II of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and is protected by the Marine Living Resources Act (No. 18 of 1998) of the national legislation. Due to the predicted small population size of this species, additional research into the abundance and potential threats facing Pygmy Killer Whales would benefit the conservation of this species in the assessment region. Although species-specific monitoring may be unnecessary, considering the rarity of this species in South African waters, sightings and strandings data should be recorded during systematic monitoring of other cetacean species.

Recommendations for managers and practitioners:
  • The severity of threats, as well as the potential synergistic effects of those threats on this species requires investigation.
  • Sightings, strandings and bycatch data should be recorded, especially during ship-based surveys aimed at other cetacean species, as well as commercial fisheries and marine tour operators.
Research priorities:
  • Data pertaining to the species’ distribution patterns and the severity of potential threats that could affect the listing of this species.
  • Estimates of population size and trends, as well as the distribution of this species within the assessment region are urgently needed.
Encouraged citizen actions:
  • Use information dispensed by the South African Sustainable Seafood Initiative (SASSI) to make good choices when buying fish in shops and restaurants, e.g. wwfsa.mobi, FishMS 0794998795.
  • Save electricity and fuel to mitigate CO2 emissions and hence, the rate of climate change.
  • Buy local products that have not been shipped.
  • Report sightings on virtual museum platforms (for example, iSpot and MammalMAP) to help with mapping geographical distribution.
  • Avoid using plastic bags.

References 

[@article{2058,
 author = {Learmonth, J.A., Macleod, C.D., Santos, M.B., Pierce, G.J., Crick, H.Q.P. and Robinson, R.A.},
 journal = {Oceanography and Marine Biology: An Annual Review},
 pages = {431--464},
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 volume = {44},
 year = {2006}
}
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 author = {Perrin  and Thewissen },
 booktitle = {Minke Whales <i>Balaenoptera acutorostrata</i> and <i>B. bonaerensis</i>},
 editor = {Perrin, W.F. and Brownell, R.L},
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,@electronic{2474,
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,@article{2762,
 author = {Sekiguchi, K., Klages, N.T.W. and Best, P.B.},
 journal = {South African Journal of Marine Science},
 pages = {843--861},
 title = {Comparative analysis of the diets of smaller odontocete cetaceans along the coast of southern Africa},
 volume = {12},
 year = {1992}
}
,@article{8551,
 author = {Wade, P.R. and Gerrodette, T.},
 journal = {Reports of the International Whaling Commission},
 pages = {477--493},
 title = {Estimates of cetacean abundance and distribution in the eastern tropical Pacific},
 volume = {43},
 year = {1993}
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,@article{8551,
 author = {Ross, G. J. B.},
 journal = {Annals of the Cape Provincial Museums (Natural History)},
 pages = {173--410},
 title = {The smaller cetaceans of the south east coast of southern Africa},
 volume = {15},
 year = {1984}
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,@article{8551,
 author = {McSweeney, D. J., Baird, R. W., Mahaffy, S. D., Webster, D. L., and Schorr, G. S. },
 journal = {Marine Mammal Science },
 pages = {557--572},
 title = {Site fidelity and association patterns of a rare species: pygmy killer whales (<i>Feresa attenuata</i>) in the main Hawaiian Islands},
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 year = {2009}
}
,@article{8551,
 author = {Bass J.},
 journal = {South African Association of Marine Biology},
 pages = {36},
 title = {A rare whale stranded in Zululand},
 volume = {7},
 year = {1968}
}
,@article{8551,
 author = {Best PB.},
 journal = {Annals of the South African Museum},
 pages = {1--14},
 title = {Records of the pygmy killer whale, <i>Feresa attenuata</i>, from southern Africa, with notes on behaviour in captivity},
 volume = {57},
 year = {1970}
}
,@article{8551,
 author = {Caldwell DK, Caldwell MC.},
 journal = {Journal of Mammalogy},
 pages = {206--209},
 title = {The pygmy killer whale, <i>Feresa attenuata</i>, in the western Atlantic, with a summary of world records},
 volume = {52},
 year = {1971}
}
,@phdthesis{8551,
 author = {Findlay KP.},
 school = {University of Pretoria},
 title = {The distribution of cetaceans off the coast of South Africa and South West Africa/Namibia},
 year = {1989}
}
,@article{8551,
 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}
}
,@electronic{8551,
 address = {http://www.iucnredlist.org},
 author = {IUCN (International Union for Conservation of Nature).},
 publisher = {The IUCN Red List of Threatened Species. Version 3.1.},
 title = {<i>Feresa attenuata</i>},
 year = {2008}
}
,@article{8551,
 author = {Jeyabaskaran R, Paul S, Vivekanandan E, Yousuf K.},
 journal = {Journal of the Marine Biological Association of India},
 pages = {208--217},
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 volume = {53},
 year = {2011}
}
,@techreport{8551,
 author = {Perryman WL, Foster TC.},
 institution = {National Oceanic and Atmospheric Administration},
 title = {Preliminary report on predation by small whales, mainly the false killer whale <i>Pseudorca crassidens</i>, on dolphins (<i>Stenella</i> spp. and <i>Delphinus delphis</i>) in the Eastern Tropical Pacific},
 year = {1980}
}
,@inbook{8551,
 address = {New York, New York, USA.},
 author = {Ridgeway  and Harrison },
 booktitle = {Pygmy Killer Whale, <i>Feresa attenuata</i> Gray, 1874},
 editor = {Ross GJB, Leatherwood S.},
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 year = {1994}
}
,@article{8551,
 author = {Yamada M.},
 journal = {Scientific Reports of the Whales Research Institute, Tokyo},
 pages = {59--88},
 title = {An account of a rare porpoise, <i>Feresa</i> Gray from Japan.},
 volume = {9},
 year = {1954}
}
,]
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