In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.
|EPBC Act Listing Status||Cetacean|
|Adopted/Made Recovery Plans|
|Policy Statements and Guidelines||
Industry Guidelines on the Interaction between offshore seismic exploration and whales (Department of the Environment and Water Resources (DEW), 2007h) [Admin Guideline].
Australian National Guidelines for Whale and Dolphin Watching (Department of the Environment and Heritage, 2005e) [Information Sheet].
|Scientific name||Feresa attenuata |
This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.
Scientific name: Feresa attenuata
Common name: Pygmy Killer Whale
The Pygmy Killer Whale was first described as Feresa attenuata by Gray, 1874 (not 1875, as usually cited; see Rice 1998 for comments). The two skulls known until the 1950s were assigned to different species but subsequent specimens obtained have shown that the Pygmy Killer Whale represents one species with a wide distribution (Bannister et al. 1996).
Pygmy Killer Whales have a somewhat slender body (Jefferson et al. 1993) that narrows towards the dorsal fin, hence the name "attenuata" (latin) meaning "thinning" (Culik 2003g). The head is round and blunt and lacks a beak. The moderately long flippers of Pygmy Killer Whales are characteristically rounded at the tips with convex leading and concave trailing edges. Pygmy Killer Whales are mostly grey to black, with a subtle dark cape on the side, below the high, falcate (sickle-shaped) dorsal fin (Culik 2003g). There is a paler grey area on each flank and an irregular white patch on the ventral side between the flippers, around the genitals and occasionally the tail stock. The lips and snout are edged with white.
Body size ranges from 2.12.6 m (Donahue & Perryman 2002), with males being slightly larger than females. Maximum weight exceeds 225 kg (Jefferson et al. 1993).
In Australia, Pygmy Killer Whales are known from strandings in NSW and Western Australia. Sighting records include five sightings of between three to more than 45 individuals at the shelf edge off Wollongong, NSW, between August 2001 to February 2002 (Ross 2006). Additional sightings have been reported in the north-east of Australia (Bannister et al. 1996; Bryden 1976).
The current extent of occurrence for Pygmy Killer Whales is estimated to be greater than 20 000 km² (based on the Australian Exclusive Economic Zone (EEZ) (200 nautical mile (nm) and north of 35° S), (Peddemors & Harcourt 2006, pers. comm.). Increasing ocean temperatures predicted by climate change scenarios could potentially increase the extent of occurrence, with warmer water extending southwards.
The area of occupancy of Pygmy Killer Whales cannot be calculated due to the paucity of records for Australia. However, it is likely to be greater than 2000 km² (Peddemors & Harcourt 2006, pers. comm.). Future expansion of high-seas pelagic fisheries may result in increased interactions with Pygmy Killer Whales, potentially increasing the rate of incidental catches and injury and leading to a decrease in the area of occupancy (Peddemors & Harcourt 2006, pers. comm.).
Pygmy Killer Whales are considered to occur in one location, as deep water is not a barrier to movement in this species, and there are no known unsurpassable ocean boundaries.
The Pygmy Killer Whale is a tropical and subtropical species that inhabits oceanic waters around the globe, generally not ranging north of 40° N or south of 35° S (Jefferson et al. 1993). Their northern range includes the Gulf of Mexico, east coast of Florida, Senegal, Arabian Sea, Sri Lanka, Honshu, Hawaii, and Gulf of Tehuantepec, and south to Buenos Aires, Cape Province, Queensland, and Peru (Rice 1998).
The distribution of the Pygmy Killer Whale is poorly known and comes from sparse but widely distributed records worldwide. They are seen relatively frequently in the eastern tropical Pacific, Hawaii and Japan, though they are probably not particularly abundant anywhere (Culik 2003g). However, their tendency to avoid boats makes accurate predictions difficult, and they may be more common than the records suggest (Carwardine 1995).
It is notable that most of the records outside the tropics are associated with strong, warm western boundary currents which effectively extend tropical conditions into higher latitudes (Culik 2003g). Records of Pygmy Killer Whales on the cool west coasts of southern Africa and Peru are exceptions, though these could represent sightings from the far warmer waters comparatively close by (Ross & Leatherwood 1994).
The Pygmy Killer Whale is a poorly known species. The only abundance estimates are for the eastern tropical Pacific, where it has been estimated that there are approximately 40 000 individuals (Wade & Gerrodette 1993).
It is unlikely that the Australian Pygmy Killer Whale represents a distinct population, as no subspecies are currently recognised. It is unknown how global threats could affect the Australian population of this species. However, as Pygmy Killer Whales are found in all deep oceanic waters at tropical and subtropical latitudes, mortalities in neighbouring countries and/or international waters may affect the Australian population (Culik 2003g).
Pygmy Killer Whales are not well surveyed within Australian waters. Their distribution is primarily assumed from incidental sightings, plus beach-cast animals, for all areas. Albeit from limited data, these methods are believed to result in reliable distributional information for the species.
No population estimates are available for Pygmy Killer Whales in Australian waters. However, they are generally considered to be in relatively low abundance (Reeves et al. 2003) and occur in group sizes less than 50 individuals. It is likely that the total number of mature animals within Australian waters is less than 10 000 (Peddemors & Harcourt 2006, pers. comm.). Pygmy Killer Whales are considered to be 'quick and lively', often wary of boats, and tend to bunch together when disturbed (Leatherwood & Reeves 1983).
Dated records for several regions (spanning several months of the year) are, at present, too few to permit assessment of the migratory status of this species (Ross & Leatherwood 1994). Incidental catches by Sri Lankan gillnet fisheries have been reported for all months except September, November and December, indicating that Pygmy Killer Whales are present almost continually throughout the year in this region. Similarly, whalers of St Vincent, Lesser Antilles, indicated that they might encounter the species at any time of the year, implying residency. Only off the coast of Wollongong, NSW, do reports of Pygmy Killer Whales appear to suggest seasonal movements, as they are only reported for the period August through to February (Ross 2006).
Although Pygmy Killer Whales have reportedly been seen in mixed species groups, such as Fraser's Dolphin (Lagenodelphis hosei), they are known to prey on other cetaceans, and elicit a distinct fright reaction from other species when held in captivity together (Ross 2006).
All cetaceans are protected within the Australian Whale Sanctuary under the EPBC Act. The Sanctuary includes all Commonwealth waters from the 3 nm State waters limit out to the boundary of the EEZ (out to 200 nm and further in some places). In addition, this species is subject to the International Whaling Comission (IWC) regulations and protected within the Indian Ocean Sanctuary and Southern Ocean Sanctuary (Bannister et al. 1996).
Pygmy Killer Whales inhabit warm tropical and subtropical waters, generally 18 °C or warmer. It is unknown whether Pygmy Killer Whales are pelagic (open ocean) or neritic (over the continental shelf), but it is thought that they are the former (Ross 2006). They are rarely seen close to shore unless around oceanic islands (Culik 2003g).
Almost nothing is known of the natural history of Pygmy Killer Whales in Australia. In other regions, Pygmy Killer Whales reach physical maturity at 2.31 m in length, however the associated age at physical maturity is unknown (Ross 2006). Sexual maturity is reached slightly earlier, at lengths of 2.16 m for males and less than 2.21 m for females (Bannister et al. 1996; Perrin & Reilly 1984; Ross 1984; Ross & Leatherwood 1994). The maximum age of Pygmy Killer Whales is more than 14 years, while the maximum length is about 2.6 m (Jefferson et al. 1993).
The natural mortality rate is unknown, but Pygmy Killer Whales are known to strand singly. Necropsies of stranded Pygmy Killer Whales indicate that heavy infestations of stomach nematodes and stomach ulcers can occur. Respiratory infections are also common in stranded individuals (Ross 2006). Stalked barnacles are known to attach to flukes, flippers and the dorsal fins (Bannister et al. 1996), but are thought to be unlikely to substantially affect healthy individuals.
Very little data exists for any of the breeding parameters of Pygmy Killer Whales. The length at birth is about 0.8 m, but there are no data on weaning or calving intervals. Similarly, no information exists regarding a Pygmy Killer Whale mating season, gestation period, calving season or calving areas (Bannister et al. 1996; Perrin & Reilly 1984; Ross 1984; Ross & Leatherwood 1994).
Food items collected from only three stomachs show that squid and fish are both eaten by this species. Sardines were eaten by a captive animal (Bannister et al. 1996; Ross 1984). Santos and Haimovici (1998) found mainly squids of the families Onychoteuthidae and, especially, Ommastrephidae in the stomach contents of Pygmy Killer Whales.
Limited behavioural observations suggest that the Pygmy Killer Whale is a predator of other cetaceans including Stenella species and the Common Dolphin (Delphinus delphis ). Pygmy Killer Whales have been observed to take dolphins as they try to escape from tuna nets in the eastern tropical Pacific (Jefferson et al. 1993).
No data is available on Pygmy Killer Whale movements in Australian waters, but limited evidence suggests this species does not migrate (Bannister et al. 1996; Ross & Leatherwood 1994). Some local movements are possible however. Off the coast of Wollongong, NSW, for example, the species has only been reported for the period August through to February (Ross 2006).
The Pygmy Killer Whale resembles the False Killer Whale (Pseudorca crassidens), but is much smaller (maximum length of the Pygmy Killer Whale is 2.7 m compared to 5.5 m of the False Killer Whale) and can be distinguished at close range by the zones of white colouration around the lips and ventrum. They may also be confused with the Melon-headed Whale (Peponocephala electra), which is similar in size and colouration. Only experienced observers can reliably distinguish between these two species from a distance, but at closer range the shape of the flippers (rounded in Pygmy Killer Whale and pointed in Melon-headed Whale) and the shape of the head (more blunt and definitely beakless in Pygmy Killer Whale, compared to tapered with a faint but sharp beak in the Melon-headed Whale) should help separate these two look-alike 'blackfish' (Leatherwood et al. 1983). Also, the white areas on the flanks of some Pygmy Killer Whales are generally absent on Melon-headed Whales. Although they may occur in larger groups, Pygmy Killer Whale groups usually contain 50 or fewer individuals.
Cetacean surveys are constrained by several important factors including weather (e.g. sea state and light conditions), area to be covered, aim of the survey (abundance estimate versus ecological studies), the activities of the animals themselves (e.g. travelling, resting, surface versus deep feeding), and the type of craft used for the survey (V. Peddemors 2006, pers. comm.).
Surveys for oceanic cetaceans such as Pygmy Killer Whales have primarily been boat-based transects. There are almost no dedicated cetacean surveys conducted in continental Australian waters. During non-dedicated surveys, a minimum requirement is to record all cetacean sightings encountered with corresponding GPS position, environmental data (sea conditions and habitat) and behavioural observations. From fishing vessels, all incidentally caught animals should be recorded with corresponding GPS position, and basic biological information from dead animals should be obtained (V. Peddemors 2006, pers. comm.).
It is believed that the past threats to Pygmy Killer Whales continue to operate today (Ross 2006).
Within Australian waters, these threats primarily include illegal and incidental catches in northern Australia. Incidental catches of Pygmy Killer Whales comprise less than 2% of all cetaceans in monitored bycatches in gillnet fisheries in Sri Lanka, possibly amounting to 300900 of the 15 00045 000 dolphins estimated to die each year in such fisheries (Ross & Leatherwood 1994). The numbers of animals killed incidentally in net fisheries may be much higher than is so far documented because monitoring of these widespread activities is incomplete. In the long term, such takes may have a significant impact on stocks in resident areas where Pygmy Killer Whales and extensive gillnetting operations overlap (Ross & Leatherwood 1994). Small incidental catches of Pygmy Killer Whales are known in fisheries in other areas (Dolar et al. 1999; Jefferson et al. 1993).
Additionally, Pygmy Killer Whales are taken in directed fisheries in several places, including Japan, Sri Lanka and Indonesia, albeit that they are taken in small numbers. Entanglement in drift-nets set outside Australian Territorial Waters and in lost or discarded netting should be considered a potentially increasing threat (Ross & Leatherwood 1994).
There are also reports on the presence of hydrocarbon residues, including DDT, Dieldrin and PCBs in various tissues of three Pygmy Killer Whales from the Gulf and Atlantic coasts of Florida (Ross & Leatherwood 1994), suggesting that increasing levels of pollution (including increasing amounts of plastic debris at sea, oil spills and dumping of industrial wastes into waterways and the sea) will lead to bio-accumulation of toxic substances in body tissues (Ross 2006).
Although little is known about reproduction in Australian Pygmy Killer Whales, it is likely that they have a low reproductive rate, producing one offspring every several years. This means that population recovery is a slow process.
Bannister and colleagues (1996) and Ross (2006) recommended the following actions be taken to better understand the threats to Pygmy Killer Whales:
- Determine the distribution and monitor abundance of Pygmy Killer Whales in Australian waters to assess the possible impact of threats, particularly the effect of direct and indirect fishing activities. This should be done via a sighting program to monitor numbers, particularly in subtropical and tropical waters. Consideration should be given to the pooling existing sightings and strandings data to locate possible concentration areas.
- Obtain information on Pygmy Killer Whale diet to determine their trophic level and assess any possible impact of the fishing industry on Odontocete food resources.
- Obtain basic biological information (including diet, pollutant levels and tissue samples for genetic analysis) from incidentally-caught and stranded Pygmy Killer Whale specimens.
Current projects initiated to address these threats include a requirement to report all incidental catches made within the Australian EEZ (Bannister et al. 1996). Disentanglement workshops have also been initiated, and may be particularly relevant to offshore fishers (Bannister et al. 1996).
The Action Plan for Australian Cetaceans (Bannister et al. 1996) and the Review of the Conservation Status of Australia's Smaller Whales and Dolphins (Ross 2006) provide brief biological overviews and management recommendations of this species. In addition, Industry Guidelines on the Interaction between offshore seismic exploration and whales (DEW 2007h), and Australian National Guidelines for Whale and Dolphin Watching (DEH 2005e) have been published.
No threats data available.
Bannister, J.L., C.M. Kemper & R.M. Warneke (1996). The Action Plan for Australian Cetaceans. [Online]. Canberra: Australian Nature Conservation Agency. Available from: http://www.environment.gov.au/coasts/publications/cetaceans-action-plan/pubs/whaleplan.pdf.
Bryden, M.M. (1976). Observations on a pygmy killer whale, Feresa attenuata, stranded on the east coast of Australia. Australian Wildlife Research. 3:21-28.
Carwardine, M. (1995). Whales, Dolphins and Porpoises. Page(s) 257 pp. London, UK: Dorling Kindersley.
Culik, B. (2003g). Feresa attenuate: Review on Small Cetaceans: Distribution, Behaviour, Migration and Threats. [Online]. www.cms.int/reports/.
Department of the Environment and Heritage (2005e). Australian National Guidelines for Whale and Dolphin Watching. [Online]. Available from: http://www.environment.gov.au/coasts/publications/whale-watching-guidelines-2005.html.
Department of the Environment and Water Resources (DEW) (2007h). Industry Guidelines on the Interaction between offshore seismic exploration and whales. [Online]. Available from: http://www.environment.gov.au/epbc/publications/seismic.html.
Dolar, M.L.L., Ponganis P.J. Suarez P & G.L. Kooyman (1999). Myoglobin in pelagic small cetaceans. Journal of Experimental Biology. 202 (3):227 - 236.
Donahue, M.A. & W.L. Perryman (2002). Pygmy Killer Whale - Feresa attenuata. In: Perrin W.F., Wursig B. & J.G.M. Thewissen, eds. Encyclopedia of Marine Mammals. Page(s) 1009-1010. San Diego, Academic Press.
Jefferson, T.A., S. Leatherwood & M.A. Webber (1993). FAO species identification guide. Marine Mammals of the World. [Online]. Rome: United Nations Environment Programme, Food and Agricultural Organization. Available from: ftp://ftp.fao.org/docrep/fao/009/t0725e/t0725e00.pdf. [Accessed: 15-Aug-2007].
Leatherwood, S. & R.R. Reeves (1983). The Sierra Club Handbook of Whales and Dolphins. San Francisco: Sierra Club Books.
Leatherwood, S., A.E. Bowles & R.R. Reeves (1983). Endangered whales of the eastern Bering Sea and Shelikof Strait, Alaska: results of aerial surveys, April 1982 through April 1983 with notes on other marine mammals seen. U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), Outer Continental Shelf Environmental Assessment Program (OCSEAP) Final Report. 42(1986):147-490.
Peddemors, V.M. (2006). Personal Communications. Sydney: Graduate School of the Environment, Macquarie University.
Peddemors, V.M. & R. Harcourt (2006). Personal Communication. Sydney: Graduate School of the Environment, Macquarie University.
Perrin, W.F. & S.B. Reilly (1984). Reproductive parameters of dolphins and small whales of the family Delphinidae. Reports of the International Whaling Commission (Special Issue 6). Page(s) 97-133.
Reeves, R.R., B.D. Smith, E.A.Crespo, & G. Notarbartolo di Sciara, eds. (2003). Dolphins, Whales and Porpoises: 2002-2010 Conservation Action Plan for the World's Cetaceans. Switzerland and Cambridge: IUCN/SSC Cetacean Specialist Group. IUCN, Gland.
Rice, D.W. (1998). Marine mammals of the world. Systematics and distribution. Special publication number 4. Kansas: Society for Marine Mammalogy.
Ross, G.J.B. (1984). The smaller cetaceans of the south-east coast of southern Africa. Annals of the Cape Provincial Museums (Natural History). 15:173-411.
Ross, G.J.B. (2006). Review of the Conservation Status of Australia's Smaller Whales and Dolphins. Page(s) 124. [Online]. Report to the Australian Department of the Environment and Heritage, Canberra. Available from: http://www.environment.gov.au/coasts/publications/pubs/conservation-smaller-whales-dolphins.pdf.
Ross, G.J.B. & S. Leatherwood, S (1994). Pygmy killer whale - Feresa attenuata Gray, 1874. In: Ridgway, S.H. & R. Harrison, R., eds. Handbook of Marine Mammals Vol. 5: The First Book of Dolphins. Page(s) 387-404. London, Academic Press.
Santos, R.A. & M. Haimovici (1998). Cephalopods in the diet of marine mammals stranded or incidentally caught along Southeast and Southern Brazil (21° to 34° S). Copenhagen Denmark: Ices.
Wade P. & T.Gerrodette (1993). Estimates of cetacean abundance and distribution in the eastern tropical Pacific. Report of the International Whaling Commission. 43:477-493.
This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.
Citation: Department of the Environment (2013). Feresa attenuata in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sat, 21 Dec 2013 23:13:48 +1100.