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 as Kogia simus|
|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||Kogia sima |
|Species author||(Owen, 1866)|
Kogia simus 
Kogia simas 
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: Kogia sima
Common name: Dwarf Sperm Whale
Although first named by Owen, 1866, the Dwarf Sperm Whale was not formally confirmed as separate from Kogia breviceps (Pygmy Sperm Whale) until 1966 (Handley 1966). The species name of the Dwarf Sperm Whale was amended from simus to sima by Rice (1998), in accordance with the gender of genus. However, the Dwarf Sperm Whale is currently listed under the EPBC Act as simus.
No subspecies are currently recognised (Bannister et al. 1996; Rice 1998).
Like other deminutive Sperm Whales (Kogia spp.), the Dwarf Sperm Whale is a small robust whale with a distinctive underslung jaw, not unlike a shark. Sperm Whales have the shortest rostrums of all cetaceans, and a skull that is markedly asymmetrical. The snout of the Dwarf Sperm Whale is more pointed than that of the Pygmy Sperm Whale. The flippers of the Dwarf Sperm Whale are set high on the sides near the head, while the falcate (sickle-shaped) dorsal fin is larger (>5% of the body length) and set nearer the middle of the back, than in the Pygmy Sperm Whale (Leatherwood & Reeves 1983).
Colouration in adult Dwarf Sperm Whales is grey on the back with a light venter (Jefferson et al. 1993). On the side of the head, between the eye and the flipper, there is often a crescent-shaped, light-coloured mark referred to as a "false gill" (McAlpine 2002). Dwarf Sperm Whales may have several short, irregular creases or grooves on the throat similar to those found on adult Sperm Whales and Beaked Whales (Leatherwood & Reeves 1983).
The Dwarf Sperm Whale is the smallest of the whales, and is even smaller than some dolphins. The maximum recorded weights for Dwarf Sperm Whales are 264 kg for females or 303 kg for males. The maximum lengths of females and males are 2.86 m and 2.62 m, respectively (Ross 2006).
Dwarf Sperm Whales are often found at the ocean surface in small groups of usually less than five individuals, but sometimes up to ten. They are thought to occur in three kinds of pods: cows and calves, immatures, and adults of both sexes (Ross 2006).
Dwarf Sperm Whales are considered oceanic, but approach coasts more than Pygmy Sperm Whales (Ross 2006). Dwarf Sperm Whales have been recorded (as stranded animals) from Western Australia, South Australia, Tasmania, NSW and the Northern Territory (Chatto & Saalfeld 2000), with only one live sighting report from South Australia (Ross 2006).
The current extent of occurrence for the Dwarf Sperm Whale is estimated to be greater than 20 000 km², calculated to the edge of the Australian Economic Exclusion Zone (EEZ) (200 nm off the coast) in areas >200 m deep (Peddemors & Harcourt 2006, pers. comm.). Increasing ocean temperatures predicted by climate change scenarios could potentially increase the extent of occurrence of Dwarf Sperm Whales, with warmer water extending southwards along both coasts.
The area of occupancy of Dwarf Sperm is likely to be greater than 2000 km² (Peddemors & Harcourt 2006, pers. comm.).
The Dwarf Sperm Whale occurs in all oceans apart from polar or sub-polar seas (Caldwell & Caldwell 1989). It primarily lives over the continental shelf and slope off tropical and temperate coasts of all oceans (Rice 1998). Although considered an oceanic species, the Dwarf Sperm Whale approaches coasts more than Pygmy Sperm Whale (Ross 2006).
Other than an estimate of 650 Dwarf Sperm Whales in the eastern Sulu Sea (Dolar 1999), there are no estimates of abundance for either Kogia species (Caldwell & Caldwell 1989). During aerial surveys in the Gulf of Mexico, Dwarf Sperm Whales accounted for only 1% of the animals seen, and occurred in 12% of the herds observed (Mullin et al. 1994). There appears to be some areas where Dwarf Sperm Whales are more commonly found, e.g. the southern tip of Africa and in the Gulf of California (Sea of Cortez), Mexico (Culik 2000). A problem for estimating abundance is that most records are from strandings, which may simply represent areas of more research effort, rather than a true picture of distribution. Lack of records of live animals may be due to the inconspicuous behaviour of Dwarf Sperm Whales, rather than rarity (Carwardine 1995; Jefferson et al. 1993).
Dwarf Sperm Whales face several threats internationally, including a limited amount of hunting that has taken place in Japan, the Lesser Antilles, Sri Lanka and Indonesia, although these whales are not major targets of exploitation (Reeves et al. 2003). Mortality in fishing nets is likely to be a more serious problem, but ingestion of plastic debris may also be an increasing threat to Dwarf Sperm Whales (Reeves et al. 2003).
Worldwide, the Dwarf Sperm Whale is not well surveyed. Their Australian distribution is primarily assumed from beach-cast animals. However, this method is believed to result in reliable distributional information for the species (Peddemores & Harcourt 2006, pers. comm.).
Dwarf Sperm Whales are not considered abundant in Australian waters as sightings and strandings are rare (DEW 2007). The species therefore potentially includes less than 10 000 mature individuals within Australian waters (Peddemores & Harcourt 2006, pers. comm.).
Elsewhere in their range, members of the genus Kogia are considered to be one of the most common species to come ashore (Caldwell & Caldwell 1989).
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 (i.e. out to 200 nautical miles and further in some places). Dwarf Sperm Whales are also subject to International Whaling Commission regulations and protected within the Indian Ocean Sanctuary and Southern Ocean Sanctuary.
The Dwarf Sperm Whale is found in pelagic habitats in temperate to tropical waters around the world (Ross 1984), but appears to prefer warmer waters than the Pygmy Sperm Whale (Carwardine 1995). The Dwarf Sperm Whale is thought to live over or near the edge of the continental shelf, while the Pygmy Sperm Whale lives in oceanic waters beyond the edge of the shelf (Caldwell & Caldwell 1989). However, this separation of the species was not apparent in the study by Mullin and colleagues (1994) who, by aerial observation, found both species over water depths of 400600 m in the North-Central Gulf of Mexico. These waters of the upper continental slope were also characterised by high zooplankton biomass (Baumgartner et al. 2001).
Female Dwarf Sperm Whales reach sexual maturity at 4.5 years and 2.15 m, males at 2.9 years and 1.97 m (Ross 2006). However, physical maturity occurs later, at about 11 years and a length of 2.5 m for females, and 15 years and 2.6 m for males (Ross 2006). The maximum recorded age is 21.5 years in females or 17 years in males, while the maximum length recorded is 2.86 m for females and 2.62 m for males (Ross 2006).
There is little information on mortality and pathology for Dwarf Sperm Whales. In Australia, they strand less frequently than Pygmy Sperm Whales (Bannister et al. 1996). Predation is assumed to be high, as the closely related Pygmy Sperm Whale has anatomical adaptations to avoid predators. The two diminutive Sperm Whale species are able to store large volumes of dark faecal liquid in the rectum, which can be ejected in a long stream when fleeing danger or disturbance (Yamada 1954). This dark fluid may also be used to camouflage a calf in potential danger (Scott & Cordaro 1987).
The breeding and claving areas used by the Dwarf Sperm Whale are unknown, but are presumed to be oceanic temperate and tropical seas (Bannister et al. 1996). Little is known about the mating system of this species. Bannister and colleagues (1996) suggest mating occurs in summer followed by a 9.5 month gestation period, and thus calving occurs the following spring. Ross (2006), however, suggests mating occurs in December to March, followed by a 12 month gestation. Calves are born at a length and weight of 1.05 m and 14 kg, respectively. Calves suckle for only about 6 months and wean at around 1.3 m in length. Dwarf Sperm Whales are thought to have a high reproductive rate, with an ovulation rate at 0.65/year and calving interval of 12 years (Ross 2006).
Studies of feeding habits, based on stomach contents of stranded Dwarf Sperm Whales, suggest that this species feeds in deep water on cephalopods and, less often, on deep-sea fishes and crustaceans (Caldwell & Caldwell 1991; Jefferson et al. 1993; Santos & Haimovici 1998). Histioteuthid and lycoteuthid squids are important prey for Dwarf Sperm Whales, and small cuttlefishes were a prime food resource in a few mother-calf pairs (Ross 1979b). Prey size is somewhat smaller than that of the Pygmy Sperm Whale (Clarke 1986; Ross 1979b, 1984).
Duguy (1994) suggests that the Dwarf Sperm Whale does not migrate extensively, since it can be observed year-round off African coasts.
As Dwarf Sperm Whales probably do not approach boats, they are very difficult to detect except in extremely calm seas (Jefferson et al. 1993). The Dwarf Sperm Whale rises to the surface slowly and deliberately and, unlike most other small whales (which roll forward at the surface), simply drops out of sight following breathing made without a blow (Culik 2000). Fortunate observers may occasionally see a breach, the Dwarf Sperm Whale leaping vertically out of the water and falling back tail-first or with a belly flop.
The tall and falcate (sickle) shape of the dorsal fin is similar to the fin of a Bottlenose Dolphin (Leatherwood & Reeves 1983). This, plus its reported propensity to float lower in the water, with less of the head and back exposed than the Pygmy Sperm Whale, may allow identification at sea (Caldwell & Caldwell 1989).
On the beach, the shark-like head, small underslung lower jaw, and light coloured "false gill" allow easy identification of this Family of whales, while the position and shape of the dorsal fin, plus the throat grooves, are the most diagnostic features for identification to species level (Jefferson et al. 1993; Leatherwood & Reeves 1983).
Dwarf Sperm Whales are notoriously difficult to identify at sea due to their propensity to spend little time at the surface, breathing only a few times before submerging for extensive periods. Whilst at the surface they are slow moving and inconspicuous, particularly as they don't 'blow'. Furthermore, their small group sizes and habit of lying motionless at the surface with the back of the head exposed and the tail hanging down loosely makes finding them difficult (Peddemores & Harcourt 2006, pers. comm.).
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 v/s ecological studies), the activities of the animals themselves (e.g. travelling, resting, surface v/s deep feeding), and the type of craft used for the survey.
Surveys for oceanic cetaceans such as Dwarf Sperm Whales have primarily been boat-based transects. There are almost no dedicated cetacean surveys conducted in Australian waters. During non-dedicated surveys, including those associated with petro-chemical explorations, the minimum recommended 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, plus attempts should be made to obtain basic biological information from dead animals (Peddemores 2006, pers. comm.).
Dwarf Sperm Whales may occasionally be killed by cetacean fisheries operating in the Lesser Antilles, Japan, Sri Lanka and Indonesia, but these whales are not generally the major targets of exploitation (Reeves et al. 2003). Mortality in fishing gear, especially gillnets, is likely to be a more serious problem. A few Dwarf Sperm Whales have been killed in Sri Lanka's gillnet fisheries, and it is likely that substantial numbers of whales are taken in gillnets in the Indian Ocean and elsewhere (Jefferson et al. 1993). Zerbini and Kotas (2001) report on bycatch of Dwarf Sperm Whales in the Brazilian driftnet fishery. Entanglement in drift nets and other nets set, lost or discarded in international waters may also threaten this species. Because of their small size and habit of lying at the surface of the ocean, apparently oblivious to approaching vessels, a few Kogia are probably also struck, injured or killed by ships (Caldwell & Caldwell 1989).
Dwarf Sperm Whales are known to ingest plastic debris, which may contribute to morbidity and mortality throughinterference with digestion of food (Laist et al. 1999). It has been suggested that the textural or visual quality of floating plastic is similar to that of squid, and thus is mistaken by whales who ingest it (Caldwell & Caldwell 1989).
Other potential threats may include competition for food from expanding commercial fisheries in lower latitudes, particularly pelagic squids, pollution leading to accumulation of toxic substances in body tissues (likely to be low), and increasing amounts of debris (ghost nets, plastic etc) in the seas (Bannister et al. 1996; Reeves et al. 2003; Ross 2006).
Bannister and colleagues (1996) and Ross (2006) recommended the following measures be undertaken to better understand the threats to Dwarf Sperm Whales:
- Determine the distribution and monitor abundance of Dwarf Sperm Whale 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.
- Obtain information on Dwarf Sperm Whale Whale diet to determine their trophic level and assess any possible impact of the fishing industry on sperm whale food resources.
- Obtain basic biological information (including diet, pollutant levels, and samples for genetic analysis) from incidentally-caught and stranded Dwarf Sperm Whale specimens.
Current projects addressing these threats include a requirement to report all incidental catches made within the Australian EEZ (Bannister et al. 1996).
Additional conservation actions suggested for Dwarf Sperm Whale include: conduct a sighting program to monitor abundance, especially in tropical and temperate waters; report and salvage specimens incidentally caught or stranded; and ensure specimens are made available to appropriate scientific museums to enable collection of life history data and tissue samples for genetic analysis (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 overviews of the species and some management recommendations. However, neither assigned a threat category to the Dwarf Sperm Whale, stating that there was insufficient information to assess trends.
In addition, the Australian National Guidelines for Whale and Dolphin Watching (DEH 2005c), the South-West Marine Bioregional Plan: Bioregional Profile: A Description of the Ecosystems, Conservation Values and Uses of the South-West Marine Region (DEWHA 2008a), the North-West Marine Bioregional Plan: Bioregional Profile: A Description of the Ecosystems, Conservation Values and Uses of the North-West Marine Region (DEWHA 2008b), and the Industry Guidelines on the Interaction between offshore seismic exploration and whales (DEW 2007h) have been prepared.
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.
Baumgartner, M.F., K.D. Mullin, L.N. May & T.D. Leming (2001). Cetacean habitats in the northern Gulf of Mexico. Fishery Bulletin. 99:219-239.
Caldwell, D.K. & M.C. Caldwell (1991). Pygmy sperm whale Kogia breviceps (de Blainville 1838): Dwarf sperm whale Kogia simus Owen, 1866. In: Ridgway, S.H. & R. Harrison, eds. Handbook of Marine Mammals Vol. 4: River Dolphins and the Larger Toothed Whales. Page(s) 235-260. London: Academic Press.
Chatto, R. & K. Saalfeld (2000). Whale strandings in the Northern Territory. II: Dwarf sperm whale Kogia simus. Northern Territory Naturalist. July 2000:15-16.
Clarke, M.R. (1986). Cephalopods in the diet of cetaceans. In: M.M. Bryden & R. Harrison, eds. Research on Dolphins. Page(s) 281-321. Clarendon Press, Oxford: Oxford Scientific Publications.
Culik, B. (2000). Kogia sima (Owen, 1866). Review on Small Cetaceans: Distribution, Behaviour, Migration and Threats. [Online]. Convention on Migratory species (CMS). Available from: http://www.cms.int/reports/small_cetaceans/index.htm. [Accessed: 12-Jul-2007].
Department of the Environment and Water Resources (DEW) (2007). National Whale and Dolphin Sightings and Strandings Database. [Online]. Available from: http://aadc-maps.aad.gov.au/aadc/whales/species_sightings.cfm?taxon_id=58. [Accessed: 12-Jul-2007].
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.
Department of the Environment, Water, Heritage and the Arts (DEWHA) (2008a). The South-West Marine Bioregional Plan: Bioregional Profile: A Description of the Ecosystems, Conservation Values and Uses of the South-West Marine Region. [Online]. Canberra: DEWHA. Available from: http://www.environment.gov.au/coasts/mbp/publications/south-west/pubs/sw-profile-full.pdf.
Department of the Environment, Water, Heritage and the Arts (DEWHA) (2008b). North-West Marine Bioregional Plan: Bioregional Profile: A Description of the Ecosystems, Conservation Values and Uses of the North-West Marine Region. [Online]. Canberra: DEWHA. Available from: http://www.environment.gov.au/coasts/mbp/publications/north-west/bioregional-profile.html.
Dolar, M.L. (1999). Abundance, distribution and feeding ecology of small cetaceans in the Eastern Sulu Sea and Taion Strait, Philippines. Ph.D. Thesis. San Diego, USA: University of California.
Duguy, R. (1994). Kogia breviceps (de Blainville, 1838) - Zwergpottwal. In: Niethammer J. & Krapp, F., eds. Handbuch der Sugetiere Europas Band 6: Meeressuger. Teil 1B: Wale unbd Delphine 2. Page(s) 598-614. Wiesbaden, Germany: Aula-Verlag.
Handley, C.O., Jr (1966). A Synopsis of the Genus Kogia (pygmy sperm whale). In: Norris, K.R., ed. Whales, Dolphins and Porpoises. Page(s) 62-69. Berkeley and Los Angeles: University of California 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].
Laist, D.W., J.M. Coe & K.J. O'Hara (1999). Marine debris pollution. In: Twiss, J.R., Jr. & Reeves, R.R., eds. Conservation and Management of Marine Mammals. Page(s) 342-366. Washington, D.C.: Smithsonian Institution Press.
Leatherwood, S. & R.R. Reeves (1983). The Sierra Club Handbook of Whales and Dolphins. San Francisco: Sierra Club Books.
McAlpine, D.F. (2002). Pygmy and dwarf sperm whales. In: Perrin, W.F., Wrsig, B. & Thewissen, J.G.M., eds. Encyclopedia of Marine Mammals. Page(s) 1007-1009. San Diego, Academic Press.
Mullin K.D., Hoggard W., Roden C.L., Lohoefener R.R., Rogers C.M. & Taggart, B. (1994). Cetaceans on the upper continental slope in the north-central Gulf of Mexico. Fishery Bulletin. 92:773-786.
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.
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. (1979b). Records of pygmy and dwarf sperm whales, genus Kogia, from southern Africa, with biological notes and some comparisons. Annals of the Cape Provincial Museums (Natural History). 11(14):259-327.
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.
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.
Scott, M.D. & J.G. Cordaro (1987). Behavioural observations of the Dwarf Sperm Whale, Kogia simus. Marine Mammal Science. 3(4):353-354.
Yamada, M. (1954). Some remarks on the Pygmy Sperm Whale, Kogia. Scientific Reports of the Whales Research Institute, Tokyo. 9:37-58.
Zerbini, A.N. & J.E. Kotas (1998). A note on cetacean bycatch in pelagic driftnetting off southern Brazil. Report of the International Whaling Commission. 48:519-524.
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). Kogia sima in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Wed, 11 Dec 2013 18:21:06 +1100.