Berardius arnuxii Duvernoy, 1851

English: Arnoux´s beaked whale
German: Südlicher Schwarzwal
Spanish: Ballenato de Arnoux, ballena picuda de Arnoux
French: Béradien d'Arnoux, baleine à bec d'Arnoux

Family Ziphiidae

Berardius arnuxii © Wurtz-Artescienza (see "links")

1. Description

The entire body is dark brown but the ventral side is paler and has irregular white patches. Tooth marks of conspecifics are numerous on the back, particularly on adult males. This being one of the largest beaked whales, adult size reaches from 8.5-9.75 m. The blowhole is crescent-shaped, the melon is small and has an almost vertical frontal surface, from which a slender rostrum projects (Kasuya, 2002, 2009). Two pairs of triangular teeth are present at and near the tip of the lower jaw and erupt in both sexes (Jefferson et al. 2008).

2. Distribution

Arnoux's beaked whales are found circumpolar in the southern hemisphere from the Antarctic continent and ice edge (78°S) north to about 34°S in the southern Pacific including south eastern Australia (29°S) and northern New Zealand (37°S), southern Atlantic to São Paulo (24°S), and Indian Ocean; but nowhere within this range are they very well known or considered common. Most of the reported sightings are from the Tasman sea and around the Albatross Cordillera in the South Pacific. The overwhelming majority of strandings have been around New Zealand (Balcomb, 1989 and refs. therein; (Jefferson et al. 1993; Rice, 1998); Baker, 1999). The species name has frequently been misspelled arnouxi or arnuxi.

Distribution of Berardius arnuxii: Waters around the Antarctic reaching northward to the shores of the Southern Hemisphere continents (mod. from Jefferson et al. 2008; Taylor et al. 2008; © IUCN.
Click here for large map)

The most northerly records are strandings, one from the coast of São Paulo state, Brazil (Martuscelli et al. 1995, 1996), the mouth of Rio de la Plata, Argentina, from the Kromme River Mouth, South Africa and from New South Wales, Australia (Paterson and Parker, 1994).

3. Population size

They are apparently not as numerous as the northern form. Arnoux's beaked whales are usually very 'shy' creatures. Like their northern congeners, they are capable of diving for an hour or more, hence are difficult to observe and positively identify. Indeed, in the Southern Hemisphere, the species could be confused with H. planifrons or T. shepherdi (Balcomb, 1989).

Arnoux's beaked whales seem to be relatively abundant in Cook Strait during summer (Carwardine, 1995). Sightings of large numbers have been reported along the western Antarctic coastal sector during the austral spring (Ponganis et al. 1995), similar to observations by Rogers and Brown (1999) for the eastern Antarctic sector. However, a more recent survey by Blume et al. (2006) failed to detect any B. arnuxii between February and April 2006 in the Amundsen and Bellingshausen Seas of the Western Antarctic. There are no detailed counts available (Barlow et al. 2006, Kasuya, 2009).

4. Biology and Behaviour

Little is known about the life history of Arnoux's beaked whale, but it is presumably similar to that of Baird's beaked whale (Balcomb, 1989).

Habitat: This species generally occurs in deep, cold temperate and subpolar waters, especially in areas with steep-bottomed slopes beyond the continental shelf edge (Kasuya 2002). Sightings have also been associated with shallow regions, coastal waters, continental slopes or sea-mounts (Rogers and Brown, 1999 and refs. therein) and other areas with steep-bottomed slopes (Carwardine, 1995).

Behaviour: Hobson and Martin (1996) observed groups of Arnoux´s beaked whales near the Antarctic Peninsula and found that their breath-hold characteristics confirm B. arnuxii as one of the most accomplished mammalian divers, capable of swimming up to an estimated 7 km between breathing sites in sea ice. Whales moved to and from the observed lead, apparently able to find other breathing sites in what appeared to be unbroken ice. The species seems well adapted to life in ice-covered waters and may be able to exploit food resources inaccessible to other predators in the region.

Schooling: Arnoux's beaked whales are gregarious, often gathering in groups of 6-10 and occasionally up to 50 or more. A group of approximately 80 of these whales was observed in Robertson Bay, Antarctica in February 1986 by Balcomb (1989). It was closely followed for several hours, after which time it split up into subgroups of 8-15 animals which dispersed throughout the bay among windrows of loose pack ice. While near the surface, the whales frequently changed direction as they swam at about 7 km/h before diving deeply out of sight for long periods. Water depths in the locality of the whales in Robertson Bay ranged from 250 - 550 meters, and the sea surface temperature was -0.8°C. Arnoux's beaked whales have been reported trapped in the ice, which may contribute to natural mortality.

Food. The feeding habits of Arnoux's beaked whales are assumed to be similar to those of their Northern Hemisphere relative, the Baird's beaked whale, thus consisting of benthic and pelagic fish and cephalopods (Jefferson et al. 1993, Kasuya 2009).

5. Migration

Arnoux's beaked whales are known to enter pack ice and may live very close to the ice edge in summer, but are likely to move away in winter (Carwardine, 1995). However, while they occur both north and south of the Antarctic Polar Front, there is no information available on seasonal shifts (Van Waerebeek et al., 2004).

6. Threats

There has not been any substantial commercial hunting of this species, but some have been taken for scientific study (Jefferson et al. 1993; Kasuya, 2009).

7. Remarks

Known and inferred Range states:
Antarctica; Argentina; Australia (South Australia, Tasmania); Brazil (São Paulo); Chile; Falkland Islands (Malvinas); Heard Island and McDonald Islands; New Zealand (Chatham Is.); South Africa (Eastern Cape Province, Western Cape Province); South Georgia; South Sandwich Islands; Uruguay (Taylor, 2008).

Very little is known about this species, and it has been classified as "Data Deficient" by the IUCN (Taylor et al. 2008). It is listed in Appendix II of CITES. The species has not been listed by the CMS (see: "selected websites").

B. arnuxii also occurs in southern South America, therefore the recommendations iterated by the scientific committee of CMS for small cetaceans in that area (Hucke-Gaete, 2000) also apply (see "Appendix 1").

8. Sources

· Baker AN (1999) Whales and Dolphins of New Zealand and Australia: an identification guide. Wellington, Victoria University Press. 133pp.
· Balcomb KC (1989) Baird's Beaked Whales - Berardius bairdii Stejneger, 1883; Arnoux Beaked Whale - Berardius arnuxii Duvernoy, 1851. In: Handbook of Marine Mammals (Ridgway SH, Harrison SR eds.) Vol. 4: River Dolphins and the Larger Toothed Whales. Academic Press, London, pp. 261-288.
· Barlow J, Ferguson MC, Perrin WF, Balance L, Gerrodette T, Joyce G, Macleod CD, Mullin K, Palka DL, Waring G (2006) Abundance and densities of beaked and bottlenose whales (family Ziphiidae). J Cetacean Res Manage 7: 263-270
· Blume M, Schmiing M, Stahl J (2007) Monitoring of whales. In "The Expedition ANT-XXIII/4 of the Research Vessel Polarstern in 2006 ((K Gohl ed.). Rep Polar Mar Res, 557: 100 -103
· Carwardine M (1995) Whales, Dolphins and Porpoises. Dorling Kindersley, London, UK, 257 pp.
· Hobson RP, Martin AR (1996) Behaviour and dive times of Arnoux's beaked whales, Berardius arnuxii, at narrow leads in fast ice. Can J Zool 74(2): 388-393.
· 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.
· Kasuya T (2002) Giant beaked whales. In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, San Diego, 519-522.
· Kasuya T (2009) Giant beaked whales Berardius bardii and B. arnuxii. In: Encyclopedia of marine mammals 2nd Ed. (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, Amsterdam, 498-500.
· Martuscelli P, Olmos F, Silva RSE, Mazzarella IP, Pino FV (1996) Cetaceans of São Paulo, southeastern Brazil. Mammalia 60(1): 125-140.
· Martuscelli P, Milanelo M, Olmos F (1995) First record of Arnoux's beaked whale (Berardius arnuxi) and Southern right-whale dolphin (Lissodelphis peronii) from Brazil. Mammalia 59(2): 274-275.
· Paterson RA, Parker AE (1994) Aerial observations of large ziphid whales, possibly Berardius arnuxii, off the southern coast of New South Wales. Mem Queensl Mus 37: 301-306.
· Ponganis PJ, Kooyman GL, Castellini MA (1995) Multiple sightings of Arnoux's beaked whales along the Victoria Land Coast. Mar Mamm Sci 11: 247-250
· 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.
· Rogers TL, Brown SM (1999) Acoustic observations of Arnoux's beaked whale (Berardius arnuxii) off Kemp Land, Antarctica. Mar Mamm Sci 15: 192-198.
· Taylor BL, Baird R, Barlow J, Dawson SM, Ford J, Mead JG, Notarbartolo di Sciara G, Wade P, Pitman RL (2008) Berardius arnuxii. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>.
. Van Waerebeek K, Leaper R, Baker AN, Papastavrou V, Thiele D (2004) Odontocetes of the Southern Ocean Sanctuary. Paper SC/56/SOS1 presented to the IWC Scientific Committee, Sorrento, Italy. 35pp.

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