Kogia sima (Owen, 1866)

English: Dwarf sperm whale
German: Kleiner Pottwal
Spanish: Cachalote enano
French: Cachalot nain

Family Kogiidae

Kogia sima © Würtz-Artescienza (see "links")

1. Description

Kogia spp. are superficially porpoise-like in body shape, and robust, with a distinctive underslung jaw, not unlike sharks. They have the shortest rostrum among cetaceans and the skull is markedly asymmetrical. Dwarf sperm whales are smaller than pygmy sperm whales and reach a maximum size of only about 2.7m total length and a body mass of 272 kg. Colouration in adults is dark bluish grey to blackish brown on the back with a light venter. 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". The teeth (up to three pairs of vestigial teeth are also found in the upper jaw) are very sharp and thin, lacking enamel (McAlpine, 2002). Baird (2005) found that photographs of several individual dwarf sperm whales showed distinctive marks on the dorsal fins, demonstrating that individual photo-identification is possible with this species.

Chivers et al. (2005) found that the results of comparisons of mitochondrial DNA and morphological differences are consistent with species- level differences between two K. sima clades, one in the Atlantic and one in the Indo-Pacific: The combined gene sequence haplotypes have accumulated 44 fixed base pair differences between these two clades compared to 20 fixed base pair differences between the recognized sister species K. sima and K. breviceps. However, recognition of a third Kogia species awaits supporting evidence that these two apparently allopatric clades represent reproductively isolated groups of animals.

2. Distribution

Kogia spp. are not easy to positively distinguish at sea (Caldwell and Caldwell, 1989), as a consequence, most reliable records of either species are based on stranded individuals or occasionally on ones taken in fisheries.

Rice (1998) summarises that K. sima lives mainly over the continental shelf and slope off tropical and temperate coasts of all oceans. Range includes the western Atlantic from Virginia south to Rio Grande do Sul in Brazil, including the Antilles; the eastern Atlantic from the Mediterranean Sea south to Cape Province; The Indian Ocean from Cape Province north to Oman, east at least as far as Lomblen in Indonesia, and south to South Australia; the western Pacific from Chiba prefecture on the east coast of Honshu, and the Mariana Islands, south to Hauraki Gulf in New Zealand; and the eastern Pacific from Vancouver Island south to Valpa-raiso in Chile (Rice, 1998). Mcalpine (2009) summarizes that K. sima prefers warmer seas than K. breviceps.

Distribution of Kogia sima: deep temperate, subtropical, and tropical waters of the northern and
southern hemispheres (Taylor et al. 2008b; © IUCN; click here for large map).

Recent strandings have been reported from Sable Island, Nova Scotia (Lucas and Hooker, 2000), the Gulf of Mexico (Delgado et al. 1998), British Columbia, Canada (Willis and Baird, 1998), the Azores (Goncalves et al. 1996), Ecuador (Felix et al. 1995), the Antilles (Debrot and Barros, 1992), the coast of France (Duguy, 1990) and Japan (Sylvestre, 1988), supporting the notion of a wide distribution in temperate zones of the world oceans.

3. Population size

Because of the lack of sightings at sea, which may be more because of its inconspicuous behaviour than true abundance, and the fact that Kogia spp. are only rarely encountered in commercial fisheries where such records may be kept, there are no real estimates of abundance for either Kogia species (Caldwell and Caldwell, 1989, Mcalpine, 2009).

The best U.S. Atlantic abundance estimate for both Kogia spp., 395 (CV=0.40), stems from two 2004 surveys, where the estimate from the northern U.S. Atlantic is 358 (CV=0.44), and from the southern U.S. Atlantic is 37 (CV=0.75). This joint estimate is considered the best because together these two surveys had the most complete coverage of the species' habitat. A separate estimate of dwarf sperm whale abundance could not be provided due to the uncertainty of species identification at sea. Furthermore, the available information was judged insufficient to evaluate trends in population size for the western North Atlantic (Waring et al. 2007).

Barlow (2006) estimates that a total of 17,519 dwarf sperm whales are found in the outer EEZ of Hawaii. Dolar (1999) estimated the population size in the eastern Sulu Sea at 650. Using corrections for missed animals, Ferguson and Barlow (2001) re-estimated the abundance as approximately 150,000 of both species in the eastern tropical Pacific.

4. Biology and Behaviour

Behaviour: Rises to the surface slowly and deliberately and, unlike most other small whales (which roll forward at the surface), simply drops out of sight. Probably does not approach boats. May occasionally breach; leaping vertically out of the water and falling back tail-first or with a belly flop. Some records suggest that, when resting at the surface, it floats lower in the water than the pygmy sperm whale. Probably dives to depths of at least 300m (Carwardine, 1995).

One of the few reported behavioural observations at sea stems from Scott and Cordado (1987) who report sighting a mother and calf after a purse-seine set was deployed on yellowfin tuna, Thunnus albacares, associated with a mixed school of spotted dolphins, Stenella attenuata, and spinner dolphins, S. longirostris. The dwarf sperm whales were accidentally encircled. While inside the net, the female released into the water a cloud of reddish material, presumably faeces, 6-8 times during the course of the set. The mother released the faeces whenever a dolphin approached the calf; she then appeared to hide herself and the calf in the middle of the opaque cloud.

In Hawaiian waters Kogia sp. were sighted most frequently in deeper portions of the study area (mean depth, 1,425 m) and in calm sea conditions (mean Beaufort sea state < 1). One group of six dwarf sperm whales containing two mother-infant pairs did not dive for more than a few minutes at a time (Baird, 2005).

Schooling: Group sizes tend to be small, most often less than 5 individuals, although groups of up to 10 have been recorded (Jefferson et al. 1993; Mcalpine, 2009).

Reproduction: In at least one area, there appears to be a calving peak in summer (Jefferson et al. 1993).

Food: Dwarf sperm whales appear to feed primarily on deep-water cephalopods (Jefferson et al. 1993) as well as on fish and crustaceans (Caldwell and Caldwell, 1989).

5. Migration

Duguy (1994) suggests that the species does not migrate extensively, since it can be observed year-round off African coasts.

6. Threats

Direct catch: Some small scale catches of dwarf sperm whales have been reported (Caldwell and Caldwell, 1989 and refs. therein). K. sima was encountered in a small harpoon fishery for pilot whales at St. Vincent in the Lesser Antilles, in Japan and occasionally in an aboriginal industry on Lomblen Island in Indonesia, and has been reported from fish markets in Sri Lanka.

Incidental catch: Caldwell and Caldwell (1989) suppose that it is unlikely that Kogia spp. are significantly affected by humans. When taken in commercial fisheries the numbers are so few that either species is considered rare. This is confirmed by Waring et al. (2007): Total annual estimated average fishery-related mortality and serious injury to the North West Atlantic stock during 1999-2003 was zero.

However, Jefferson et al. (1993) believe that substantial numbers are taken each year in gillnets in the Indian Ocean, and possibly elsewhere. Zerbini and Kotas (2001) report on by-catch in the Brazilian driftnet fishery. Because of their small size and habit of often lying at the surface, apparently oblivious to approaching vessels, a few Kogia are probably run down and injured or killed (Caldwell and Caldwell, 1989).

Pollution: Both species have been reported with plastic bags in their stomachs that may have prevented digestion of food and ultimately brought death. Perhaps the textural or visual quality of the plastic was similar to that of squid and thus enticed the whales to devour it (Caldwell and Caldwell, 1989).

7. Remarks

Range states (Taylor et al. 2008b):
American Samoa; Angola; Anguilla; Antigua and Barbuda; Argentina; Aruba; Australia; Bahamas; Bangladesh; Barbados; Belize; Benin; Bermuda; Brazil (Rio Grande do Sul); Brunei Darussalam; Cambodia; Cameroon; Canada (British Columbia); Cape Verde; Cayman Islands; Chile (Valparaíso); China; Colombia; Congo; Congo, The Democratic Republic of the; Cook Islands; Costa Rica; Cuba; Côte d'Ivoire; Djibouti; Dominica; Dominican Republic; Ecuador (Galápagos); El Salvador; Equatorial Guinea; Fiji; France; French Guiana; French Polynesia; Gabon; Gambia; Ghana; Gibraltar; Grenada; Guadeloupe; Guam; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; Hong Kong; India; Indonesia; Iran, Islamic Republic of; Jamaica; Japan (Honshu); Kenya; Kiribati; Kuwait; Liberia; Madagascar; Malaysia; Maldives; Marshall Islands; Martinique; Mauritania; Mexico; Micronesia, Federated States of; Morocco; Mozambique; Myanmar; Namibia; Nauru; Netherlands Antilles; New Caledonia; New Zealand (Kermadec Is., North Is.); Nicaragua; Nigeria; Niue; Northern Mariana Islands; Oman; Pakistan; Palau; Panama; Papua New Guinea; Peru; Philippines; Pitcairn; Portugal (Azores, Madeira); Puerto Rico; Qatar; Réunion; Saint Helena; Saint Kitts and Nevis; Saint Lucia; Saint Pierre and Miquelon; Saint Vincent and the Grenadines; Samoa; Sao Tomé and Principe; Senegal; Sierra Leone; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Suriname; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Togo; Tonga; Trinidad and Tobago; United Arab Emirates; United States of America (Hawaiian Is.); Venezuela; Viet Nam; Virgin Islands, British; Virgin Islands, U.S.; Wallis and Futuna; Western Sahara; Yemen

Classified as "Data Deficient" by the IUCN. Not listed by CMS. The species is listed in Appendix II of CITES.

Both kogiid species also occur in southern South America. Recommendations iterated by the scientific committee of CMS for small cetaceans in that area (Hucke-Gaete, 2000) also apply (see Appendix 1). For recommendations on south-east Asian stocks, see Perrin (1996) in Appendix 2.

8. Sources

· Abollo E, Lopez A, Gestal C, Benavente P, Pascual S (1998) Macroparasites in cetaceans stranded on the northwestern Spanish Atlantic coast. Dis Aquat Organisms 32: 227-231.
· Baird R W, Nelson D, Lien J, Nagorsen DW (1996) The status of the Pygmy Sperm Whale, Kogia breviceps, in Canada. Can Field Nat 110: 525-53.2
· Baird RW (2005) Sightings of Dwarf (Kogia sima) and Pygmy (K. breviceps) Sperm Whales from the Main Hawaiian Islands. Pac Sci 59: 461-466
· Barlow J (2006) Cetacean abundance in Hawaiian waters estimated from a summer/fall survey in 2002. Mar Mamm Sci 22: 446-464
. Bastida R, Rodríguez D (2003) Mamíferos Marinos de Patagonia y Antártida. 1ra. Ed. Buenos Aires. Vázquez Maziini Editores, 208 pp.
· Baumgartner MF, Mullin KD, May LN, Leming TD (2001) Cetacean habitats in the northern Gulf of Mexico. Fish Bull 99: 219-239.
· Beatson E (2007) The diet of pygmy sperm whales, Kogia breviceps, stranded in New Zealand: implications for conservation. Rev. Fish Biol. Fish 17: 295-303
· Bustamante P, Garrigue C, Breau L, Caurant F, Dabin W, Greaves J, Dodemont R (2003) Trace elements in two odontocete species (Kogia breviceps and Globicephala macrorhynchus) stranded in New Caledonia (South Pacific). Environ Pollut 124 : 263-271.
· Caldwell DK Caldwell MC (1989) Pygmy sperm whale Kogia breviceps (de Blainville, 1838); Dwarf sperm whale Kogia simus Owen, 1866. In: Handbook of Marine Mammals (Ridgway SH, Harrison SR, eds.) Vol. 4: River Dolphins and the Larger Toothed Whales. Academic Press, London, pp. 235-260.
· Carwardine M (1995) Whales, Dolphins and Porpoises. Dorling Kindersley, London, UK, 257 pp.
· Chivers SJ, Leduc RG, Robertson KM, Barros NB, Dizon AE (2005) Genetic Variation of Kogia spp. with Preliminary Evidence for Two Species of Kogia sima. Mar. Mamm. Sci.]. Vol. 21, no. 4, pp. 619-634
· Debrot AO, Barros NB (1992) Notes on a Gervais' beaked whale, Mesoplodon europaeus, and a dwarf sperm whale, Kogia simus, stranded in Curacao, Netherlands Antilles. Mar Mamm Sci 8: 172-178.
· Delgado Estrella A, Villa RB, Vazquez MLE (1998) First records of dwarf sperm whale (Kogia breviceps) pygmy sperm whale (K. simus) and pygmy killer whale (Feresa attenuata) in Veracruz, Mexico. An Inst Biol Univ Nac Auton Mex Zool 69: 129-134.
· Dolar ML (1999) Abundance, distribution and feeding ecology of small cetaceans in the Eastern Sulu Sea and Tañon Strait, Philippines. PhD thesis, U Cal San Diego, USA.
· Duffield DA, Barros NB, Espinoza EO, Ploen S, Gulland FMD, Heyning JE (2003) Identifying pygmy and dwarf sperm whales (genus Kogia) using electrospray ionization mass spectrometry of myoglobin and hemoglobin. Mar Mamm Sci 19: 395-399
· Duguy R (1990) Cetacea stranded on the coasts of France during the last ten years. Copenhagen Denmark Ices, 5 pp.
· Duguy R (1991) Annual report of Cetacea and Pinnipedia recorded from the coasts of France. Copenhagen Denmark Ices, 2 pp.
· Duguy R (1994) Kogia breviceps (de Blainville, 1838) - Zwergpottwal. In: Niethammer J, Krapp F (eds.) Handbuch der Säugetiere Europas. Band 6: Meeressäuger. Teil 1B: Wale unbd Delphine 2. Aula-Verlag, Wies-baden, Germany, pp. 598-614.
· Eldredge LG (1991) Annotated checklist of the marine mammals of Micronesia. Micronesica 24: 217-230.
· Felix F, Haase B, Samaniego J (1995) First record of pygmy killer whale Feresa attenuata (Cetacea: Delphinidae) and dwarf sperm whale Kogia simus (Cetacea: Physeteridae) on the ecuadorean continental coast. Estud Oceanol 14: 77-85.
· Ferguson MC, Barlow J (2001) Spatial distribution and density of cetaceans in the eastern tropical Pacific Ocean based on summer/fall research vessel surveys in 1986-96.Report No. LJ-01-04, Southwest Fisheries Science Center, La Jolla, CA
· Goncalves JM, Barreiros JP, Azevedo JMN, Norberto R (1996) Cetaceans stranded in the Azores during 1992-96. Arquipelago Cienc Biol Mar; Life Mar Sci 14A: 57-65.
· Handley COJr (1966) A Synopsis of the Genus Kogia (pygmy sperm whale). In: Norris, K.R., ed. Whales, Dolphins and Porpoises. pp 62-69. Berkeley and Los Angeles: University of California Press.
· Hucke-Gaete R (2000) Review of the conservation status of small cetaceans in southern South America. UNEP/CMS Secretariat, Bonn, German, 24 pp.
· Jefferson TA, Leatherwood S, Webber MA (1993) FAO Species identification guide. Marine mammals of the world. UNEP/FAO, Rome, 320 pp.
· Kemper CM, Ling JK (1991) Whale strandings in south Australia (1881-1989) Trans Royal Soc S Austr 115: 37-52
· Lucas ZN, Hooker SK (2000) Cetacean strandings on Sable Island, Nova Scotia, 1970-1998. Can Field Nat 114: 45-61.
· Marcovecchio JE, Gerpe MS, Bastida RO, Rodriguez DH, Moron SG (1994) Environmental contamination and marine mammals in coastal waters from Argentina: An overview. Sci Total Environ 154: 141-151.
· Martin JW, Heyning JE (1999) First record of Isocyamus kogiae Sedlak-Weinstein, 1992 (Crustacea, Amphipoda, Cyamidae) from the eastern Pacific, with comments on morphological characters, a key to the genera of the Cyamidae, and a checklist of Cyamids and their hosts. Bull S Cal Acad Sci 98: 26-38.
· Mazzuca L, Atkinson S, Keating B, Nitta E (1999) Cetacean mass strandings in the Hawaiian Archipelago, 1957-1998. Aquat Mamm 25: 105-114.
· McAlpine DF (2002) Pygmy and dwarf sperm whales. In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, San Diego, pp. 1007-1009.
· McAlpine DF (2009) Pygmy and dwarf sperm whales. In: Encyclopedia of marine mammals, 2nd Ed. (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, Amsterdam, pp. 936-938.
· Mullin KD, Hoggard W, Roden CL, Lohoefener RR, Rogers CM, Taggart B (1994) Cetaceans on the upper continental slope in the north-central Gulf of Mexico. Fish Bull 92: 773-786.
· Parsons ECM, Dolman SJ, Wright AJ, Rose NA, Burns WCG (2008) Navy sonar and cetaceans: Just how much does the gun need to smoke before we act? Mar Poll Bull 56: 1248-1257
· Perez C, Lopez A, Sequeira M, Silva M, Herrera R, Goncalves J, Valdes P, Mons L, Freitag L, Lens S, Cendrero O (2001) Stranding and by-catch of cetaceans in the Northeastern Atlantic during 1996. Copenhagen Denmark Ices, 4 pp.
· Perrin WF, Dolar MLL, Alava MNR (1996) Report of the workshop on the biology and conservation of small cetaceans and dugongs of Southeast Asia. East Asia Seas Action Plan. UNEP(W)/EAS WG. 1/2, Bangkok, Thailand.101 pp.
· Rice DW (1998) Marine mammals of the world: systematics and distribution. Society for Marine Mammalogy, Special Publication Number 4 (Wartzok D, Ed.), Lawrence, KS. USA.
· Sanino GP, Yanez J (1997) Study of Kogia breviceps in Chilean coastal waters. Museo Nacional de Historia Natural Boletin Santiago 46: 81- 93
· Santos RA, Haimovici M (1998) Cephalopods in the diet of marine mammals stranded or incidentally caught along Southeast and Southern Brazil (21° to 34° S). Copenhagen Denmark Ices 15 pp
· Scott MB, Hohn AA, Westgate AJ, Nicolas JR, Whitaker BR, Campbell WB (2001) A note on the release and tracking of a rehabilitated pygmy sperm whale Kogia breviceps. J Cetacean Res Nanage 3 : 87-94
· Scott MD, Cordaro JG (1987) Behavioral observations of the dwarf sperm whale, Kogia simus. Mar Mamm Sci 3: 353-354.
· Sedlak-Weinstein E (1992) A new species of Isocyamus (Amphipoda: Cyamidae) from Kogia breviceps (De Blainville, 1838) in Australian waters. Syst Parasit 23: 1-6.
· Smith BD, Jefferson TA, Leatherwood S, Ho Dao Tan, Van Thuoc Chu, Hai Quang Le (1997) Investigations of marine mammals in Vietnam. Asian Mar Biol 14: 145-172.
· Stamper MA, Whitaker BR, Schofield TD (2006) Case study. Morbidity in a pigmy sperm whale, Kogia breviceps, due to ocean-borne plastic. Mar Mamm Sci 22:719-722
· Sylvestre JP (1988) Note on three dwarf sperm whales Kogia simus (Owen, 1866) and comments on Kogiids of Japanese Coasts. Aquat Mamm 14: 120-122.
· Tarpley RJ, Marwitz S (1993) Plastic debris ingestion by cetaceans along the Texas coast: Two case reports. Aquat Mamm 19: 93-98.
· Taylor BL, Baird R, Barlow J, Dawson SM, Ford J, Mead JG, Notarbartolo di Sciara G, Wade P, Pitman RL (2008) Kogia breviceps. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>
· Taylor BL, Baird R, Barlow J, Dawson SM, Ford J, Mead JG, Notarbartolo di Sciara G, Wade P, Pitman RL (2008) Kogia sima. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>.
· Wang, Ming-Chih; Walker, WA; Shao, Kwang-Tsao; Chou, Lien-Siang (2002) Comparative analysis of the diets of pygmy sperm whales and dwarf sperm whales in Taiwanese waters. Acta Zool Taiwan 13: 53-62.
· Waring GT, Josephson E, Fairfield CP, Maze-Foley K, editors (2007) U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments -- 2006. NOAA Tech Memo NMFS NE 201; 378 p.
· Watanabe M, Kannan K, Takahashi A, Loganathan BG, Odell DK, Tanabe S, Giesy JP (2000) Polychlorinated biphenyls, organochlorine pesticides, tris(4-chlorophenyl)methane, and tris(4-chlorophenyl)methanol in livers of small cetaceans stranded along Florida coastal waters, USA. Env Tox Chem 19: 1566-1574.
· Willis PM, Baird RW (1998) Status of the dwarf sperm whale, Kogia simus, with special reference to Canada. Can Field Nat 112: 114-125.
· Zerbini AN, Kotas JE (1998) A note on cetacean bycatch in pelagic driftnetting off southern Brazil. Rep Int Whal Comm 48: 519-524.

© Boris Culik (2010) Odontocetes. The toothed whales: "Kogia sima". UNEP/CMS Secretariat, Bonn, Germany. http://www.cms.int/reports/small_cetaceans/index.htm
© Illustrations by Maurizio Würtz, Artescienza.
© Maps by IUCN.