Hyperoodon planifrons Flower, 1882

English: Southern bottlenose whale
German: Südlicher Entenwal
Spanish: Zifio calderón austral
French: Hypéroodon austral

Family Ziphiidae

Hyperoodon planifrons © Würtz-Artescienza (see "links")

1. Description

H. planifrons resembles the northern bottlenose whale, with a robust body. It reaches a body length of up to 7.8 m (Jefferson et al. 2008), maximum weight is about 4,000 kg (Ross 2006). Southern bottlenose whales have a large, bulb-shaped forehead and short, dolphin-like beak. Their colour is chocolate brown to yellow, being lighter on the flanks and belly. Some of this colouration is believed to be caused by a thin layer of diatoms. Mature males have a squared-off forehead, whereas in females and immature males it is rounded. Males possess a single pair of conical teeth at the tip of the lower jaw, rarely visible in live animals (Gowans, 2009). Juveniles have diagnostic, bold, cream-white facial fields separated by a distinct dark blowhole stripe (Van Waerebeek et al. 2005).

2. Distribution

Southern bottlenose whales are thought to have a circumpolar distribution in the Southern Hemisphere, south of 30°S (Mead, 1989; Jefferson et al. 1993). They occur from Rio Grande do Sul in Brazil, Cape Province in South Africa, 31°S in the western Indian Ocean, Dampier Archipelago in Western Australia, Ulladulla in New South Wales, North Island in New Zealand, and Valparaiso in Chile, south to the Antarctic continent (Rice, 1998).

Distribution of H. planifrons (mod. from Taylor et al. 2008; © IUCN): The species inhabits the cold,
deep waters of the Southern Hemisphere, circumpolar from Antarctica North to about 28°40'°S (Van Waerebeek et al. 2004; click here for a larger map).

Sightings off Durban, South Africa, show strong seasonality with peaks in February and October, the February peak possibly suggesting a general movement northward out of the Antarctic in late summer (Sekiguchi et al., 1993; Van Waerebeek et al., 2004).

The records from north-western Australia and from Brazil indicate that H. planifrons also occurs in warm temperate waters.

3. Population size

Southern bottlenose whales are the most common beaked whales sighted in Antarctic waters: In 1995, Kasamatsu and Joyce (1995) published abundance estimates for south of the Antarctic Convergence in January: 599,300 beaked whales, more than 90% of which are southern bottlenose whales (Kasamatsu et al. 1988). However, according to Gowans (2009) there are no known areas of concentration.

4. Biology and Behaviour

Habitat: H. planifrons is most common beyond the continental shelf and over submarine canyons, in water deeper than 1,000m. It is rarely found in water less than 200m deep. In summer, this species is most frequently seen within about 100 km of the Antarctic ice edge, where it appears to be relatively common (Carwardine, 1995). Cockcroft et al. (1990) report sightings in the steep thermocline between the Agulhas current and cold Antarctic water masses.

Photo © AWI-Bremerhaven (see "links").

Behaviour: The southern bottlenose whale is poorly known and rarely observed at sea. It lives far from shipping lanes, and has never been commercially exploited, so it has not been as well studied as its northern counterpart. There are few reports of swimming near boats, but this may be due to lack of observation rather than shyness. After long dives, it may remain on the surface for 10 minutes or more, blowing every 30 to 40 seconds. It can stay underwater for at least an hour, but typical dive time is shorter. When swimming fast, especially under stress, it may raise its head clear of water on surfacing. Probably a deep diver, though it does not tend to travel much horizontal distance while submerged (Carwardine, 1995). There is essentially nothing known of the reproductive biology of this species (Jefferson et al. 1993).

Schooling: Pods of less than 10 are most common, but groups of up to 25 have been seen, exceptionally up to 40 (Bastida and Rodríguez, 2003).

Food: Diet analyses compiled by MacLeod et al. (2003) for H. planifrons report 41 species of cephalopod species from 17 families. Where information on prey was available, Onychoteuthid, Cranchiid, Gonatid and Histioteuthid species contributed almost all of the biomass in H. planifrons. The largest individual prey item reported was 4080 g. Fish were reported only once, in small numbers. However, this may be attributed to differential digestion rates of cephalopod and fish remains as the stomachs examined came from stranded animals (e.g. Slip et al., 1995).

5. Migration

Southern bottlenose whales apparently migrate, and are found in Antarctic waters during the summer. Like other beaked whales, they are deep-water oceanic animals (Jefferson et al. 1993). Kasamatsu and Joyce (1995) investigated the spatial distribution of various cetacean species during mid-summer in Antarctic waters and found different peaks of occurrence for each species by latitude, suggesting possible segregation. Killer whales occur mainly in the very southernmost areas, sperm whales in the southern half of the study area, whereas beaked whales (mostly southern bottlenose whales) ranged over a wide area.

Sightings of southern bottlenose whales off Durban between February and October showed a strong seasonality with peaks in February and October. The beaks of Antarctic and subantarctic squids in the stomachs of two specimens stranded in South African waters, plus the presence of cold water skin diatoms Bennettella (= Cocconeis) ceticola suggest that the animals had arrived comparatively recently from higher latitudes (Sekiguchi et al. 1993).

6. Threats

Although never taken commercially, some southern bottlenose whales have been killed during whaling operations by Soviet and Russian whalers and others based at South Shetlands and South Georgia, some of these for research purposes (Bastida and Rodríguez, 2003; Van Waerebeek et al. 2004). Several have been recorded as accidental victims of driftnet fishing in the Tasman Sea. Numbers taken annually are not known (Jefferson et al. 1993).

7. Remarks

Range states: Antarctica; Argentina; Australia; Brazil; Chile; Falkland Islands (Malvinas); New Zealand; South Africa; Uruguay (Taylor et al. 2008).

H. planifrons is categorised as "Least concern" by the IUCN (Taylor et al. 2008) and is listed in Appendix I & II of CITES. It is not listed by CMS.

H. planifrons also occurs 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 et al. (1996) in Appendix 2.

8. Sources

· Bastida, R. and Rodríguez, D. 2003. Mamíferos Marinos de Patagonia y Antartida. Vazquez Mazzini Editores, Buenos Aires. 206pp.
· Carwardine M (1995) Whales, Dolphins and Porpoises. Dorling Kindersley, London, UK, 257 pp.
· Cockroft VG, Peddemors VM, Ryan PG, Lutjeharms JRE (1990) Cetacean sightings in the Agulhas retroflection, Agulhas rings and subtropical convergence. South African Journal Of Antarctic Research 20(2): 64-67
· Gowans S (2009) Bottlenose whales Hyperoodon ampullatus and H. planifrons. In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, San Diego, pp. 129-131.
· 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.
Jefferson TA, Webber MA Pitman RL (2008) Marine mammals of the world. Elsevier, Amsterdam, 573 pp.
· Kasamatsu F, Joyce GG (1995) Current status of Odontocetes in the Antarctic. Antarctic Science 7(4): 365-379
· Kasamatsu F, Hembree D, Joyce G, Tsunoda L, Rowlett R, Nakano T. (1988) Distribution of cetaceans sightings in the Antarctic: results obtained from the IWC/IDCR minke whale assessment cruises, 1978/79 to 1983/84. Rep. Int. Whal. Commn 38: 449-485.
· MacLeod CD, Santos MB, Pierce GJ (2003) Review of data on diets of beaked whales: evidence of niche separation and geographic segregation. J Mar Biol Ass UK 83: 651-665
· Mead JG (1989) Bottlenose whales - Hyperoodon ampullatus (Forster, 177) and Hyperoodon planifrons Flower, 1882. In: Handbook of Marine Mammals (Ridgway SH, Harrison SR eds.) Vol. 4: River Dolphins and the Larger Toothed Whales. Academic Pres, London, pp. 321 - 348.
· 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.
Ross GJB (2006) Review of the Conservation Status of Australia's Smaller Whales and Dolphins. Australian Government, 124 pp.
· Sekiguchi K, Klages N, Findlay K, Best PB (1993) Feeding habits and possible movements of southern bottlenose whales (Hyperoodon planifrons). Proc Nipr Symp Polar Biol 6:84-97
· Slip DJ, Moore GJ, Green K (1995) Stomach contents of a southern bottlenose whale, Hyperoodon planifrons, stranded at Heard Island. Mar Mamm Sci 11: 575-580
· Taylor BL, Baird R, Barlow J, Dawson SM, Ford J, Mead JG, Notarbartolo di Sciara G, Wade P, Pitman RL (2008) Hyperoodon planifrons. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>
· Van Waerebeek K, Findlay K, Friedrichsen G, Best PB (2005) Bold colouration pattern in southern bottlenose whales, a preliminary assessment of external variation. IWC Scientific Committee Document SC/57/SM12.
· Van Waerebeek K, Leaper R, Baker AN, Papastavrou V, Thiele D (2004) Odontocetes of the Southern Ocean Sanctuary. IWC Scientific Committee Document SC/56/SOS1, July 2004, Sorrento, Italy. 25pp.

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