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 Berardius arnuxii|
|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].
|State Listing Status||
|Scientific name||Berardius arnuxii |
|Other names||Berardius arnouxi |
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: Berardius arnuxii
Common name: Arnoux's Beaked Whale
Recent genetic research indicates that Arnoux's Beaked Whale is a distinct and well-defined species, separated from its Northern Hemisphere relative Baird's Beaked Whale (Berardius bairdii) for several million years (Dalebout 2002). Prior to this taxonomic revision, the relationship between Arnoux's and Baird's Beaked Whales was uncertain, in part a reflection of the relatively few specimens available for comparison and the slight morphological differences between them.
Arnoux's Beaked Whales exhibit many of the standard features of beaked whales: they have a small head with a dolphin-like beak; a moderately steep bulbous forehead with a visible concavity in the front; and an elongated rotund body with a proportionally small falcate dorsal fin positioned more than two-thirds of the way towards the flukes. The tail flukes have no median notch and the trailing edge is almost straight. The flippers are rounded at the tips. The crescent-shaped blow-hole is at the centre of the top of the head with the rounded side facing anteriorly. This orientation of the blowhole is unique to the genus Berardii (Leatherwood & Reeves 1983).
As with many beaked whales, the lower jaw extends beyond the upper and both males and females have a pair of triangular, laterally compressed teeth that erupt near the tip of the mandibles. A second smaller pair of teeth is further back and only erupts later in life. A characteristic feature of Arnoux's Beaked Whale is that the apical teeth are exposed outside the mouth. The throat has the usual pair of V-shaped creases present in beaked whales.
The colour pattern of Arnoux's Beaked Whales is not well described because descriptions have largely been based on the partly decomposed carcasses of stranded whales. However, the body appears to be largely counter-shaded, with dark grey colouration above and lighter below. There are often several dark diagonal bands on the sides (Jefferson at al. 1993). Heavy body scarring in older animals has been presumed to result from of agonistic encounters with other Arnoux's Beaked Whales, in which they use their teeth as weapons, or from Killer Whale attacks. Estimates suggest 40% of bodily scarring may be from Killer Whale attacks (Ross 2006).
The maximum length of Arnoux's Beaked Whales is about 9.4 m in both sexes (Ross 2006). They are gregarious whales, usually forming small groups of up to 16 individuals (Paterson & Parker 1994). Occasional schools of up to 50 animals have been observed off NSW, while one group of about 80 was observed to split up into subgroups of eight to 15 individuals which subsequently dispersed (Ross 2006).
Arnoux's Beaked Whales are known from only five stranded specimens in Australia (South Australia, south-west Western Australia (two), Tasmania and the subAntarctic). Possible sightings of Arnoux's Beaked Whales inshore off South Australia and the south coast of NSW have also been recorded (Ross 2006). Confirmed sightings have been made in the Australian Antarctic territorial waters (Peddemors 2006b, pers. obs.). Most sightings have been made in the Tasman Sea and around the East Pacific Rise, which forms part of the Albatross Cordillera in the South Pacific Ocean. No key localities are known in Australian waters (Bannister et al. 1996).
The current extent of occurrence for Arnoux's Beaked Whale is estimated to be greater than 20 000 km² (based on the Australian Economic Exclusion Zone (200 nautical mile, between 34° S and 50° S and generally deeper than 200 m) (Peddemors & Harcourt 2006, pers. comm.). Increasing ocean temperatures predicted by climate change scenarios could potentially decrease the extent of occurrence, with warmer water extending southwards beyond 34° S.
The area of occupancy of Arnoux's Beaked Whale cannot be calculated due to the sparsity 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 gillnet fisheries could potentially result in increased incidental catches, reducing local population size and leading to a decrease in area of occupancy.
Arnoux's Beaked Whales are considered to occur in one location as deep water is not a barrier to movement in this species.
No distribution fragmentation is anticipated for Arnoux's Beaked Whale in Australian oceanic Antarctic, subantarctic and cold temperate waters.
Arnoux's Beaked Whale occurs circumglobally in the Southern Ocean from about latitude 34° S southwards to the Antarctic ice. Their range therefore includes temperate waters of 1020 °C through to Antarctic waters of between 05 °C (Bannister et al. 1996).
There are no estimates of Arnoux's Beaked Whale population size, either globally or for Australia, so the proportion of the global population occurring in Australian waters is unknown. It is unlikely that Australian Arnoux's Beaked Whales are a distinct population, as no subspecies are currently recognized. As Arnoux's Beaked Whale is a deep water species primarily living off the continental shelf, incidental bycatch of animals in neighbouring countries and/or international waters may affect the Australian population.
World-wide, Arnoux's Beaked Whale is not well surveyed. Their distribution is primarily assumed from incidental sightings, plus beach-cast animals, for all areas other than the Antarctic where whale surveys have been conducted.
There are no available estimates of the population size of Arnoux's Beaked Whales, although they are not considered abundant as sightings and strandings are rare (Bannister et al. 1996).
All cetaceans are protected within The Australian Whale Sanctuary under the EPBC Act. The Sanctuary includes all Commonwealth waters from the 3 nautical mile (nm) state waters limit out to the boundary of the Exclusive Economic Zone (out to 200 nm and further in some places). Arnoux's Beaked Whale is also subject to International Whaling Commission (IWC) regulations and protected within the Indian Ocean Sanctuary and Southern Ocean Sanctuary.
Arnoux's Beaked Whales are considered an oceanic species. They are seldom seen over continental shelves, but are common in deep oceanic waters, particularly close to regions carrying higher prey densities, such as sea mounts and submarine escarpments (Balcomb 1989; Brownell 1974; Leatherwood and Reeves 1983). Arnoux's Beaked Whales have occasionally been observed along the ice edge in summer south of the Indian Ocean (SOCEP unpublished data). However, the timing of these sightings this may reflect a bias in survey effort during the summer.
Life history data for Arnoux's Beaked Whale are extremely limited. Comparisons with Baird's Beaked Whale (B. bairdii) have been used to provide some indication of expected life history. Age at sexual maturity is expected to be about eight to 10 years of age, as for Baird's Beaked Whale, when males and females have reached 8.5 m and 9.0 m long, respectively (Bannister et al. 1996). Age and length at physical maturity is probably around 20 years and 9.0 m, respectively. The maximum age of Arnoux's Beaked Whale is unknown, but probably exceeds 50 years, as in Baird's Beaked Whale. Arnoux's Beaked Whales are presumed to be subject to attacks by Killer Whales (which are estimated to cause 40% of scarring on Baird's Beaked Whale). Occasionally Arnoux's Beaked Whales die after becoming trapped in pools formed in sea ice adjacent to the Antarctic continent (Bannister et al. 1996).
No data have been recorded for any specific breeding parameter of Arnoux's Beaked Whale (Ross 2006). There are no known reproductive behaviours that may make Arnoux's Beaked Whale vulnerable to a threatening process, although a suspected calving interval of three years leads to a slow reproductive capacity.
Little is known about the diet of Arnoux's Beaked Whale. The stomach of one New Zealand specimen contained a large quantity of cephalopod beaks, identified as 'the common sea spider or octopus'. The Northern Hemisphere Baird's Beaked Whale feeds on mid- and deep-water squids, octopus and fishes, but also takes pelagic fishes such as mackerel, sardines, pollack and saury (Bannister et al. 1996).
A powerful and active predator, Arnoux's Beaked Whale is presumed to be able to dive in excess of 1000 m in pursuit of prey, but their method of capture is not known. As Arnoux's Beaked Whales lack functional gripping teeth, prey may be seized and disabled using the hard edges of the mandibles and the rostral palate. The precise function of the pair of the V-shaped throat grooves (a feature of ziphiids) is unknown, but their arrangement suggests a capacity for distension to create a sucking pressure, that may facilitate passage of large whole prey down the oesophagus past the aryteno-epiglottideal tube (Ross 2006).
Although Arnoux's Beaked Whales are difficult to detect, their dark colouration, dorsal fin shape, head shape and position of the teeth enable them to be distinguished from Southern Bottlenose Whales, with which they share much of their range. Arnoux's Beaked Whale may also be confused with Baird's Beaked Whale. The most distinctive difference between the two species is the larger length of Baird's (11.5 m) compared to the Arnoux's Beaked Whale (9.4 m) (Rice 1998).
The exposed apical teeth will often flash brightly in sunlight, making them especially noticeable. In addition, the orientation if the crescent-shaped blow-hole, with the rounded side facing anteriorly, is unique to the genus Berardii (Leatherwood & Reeves 1983).
Beaked 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'. Arnoux's Beaked Whales dive deeply for around 1530 minutes, possibly to depths of 1000 m or more, and may resurface at a considerable distance from the start of the dive. They are very shy of vessels.
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.
Surveys for oceanic cetaceans such as beaked whales have primarily been boat-based transects. There are almost no dedicated cetacean surveys conducted in Australian waters, but surveys conducted in the Antarctic and sub-Antarctic have covered substantial portions of potential range of Arnoux's Beaked Whales. 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. Peddermons, 2006 pers.comm.)
The current threats to Arnoux's Beaked Whale include possible entanglement in drift nets and other nets set, lost or discarded in international waters. Other potential threats may include competition from expanding commercial fisheries in higher latitudes, such as those for Orange Roughy, Patagonian Toothfish and cephalopods (squids), and from pollution leading to accumulation of toxic substances in body tissues, although the threat from the latter issue are likely to be low (Bannister et al. 1996; Ross 2006).
Recently, there have been a number of studies investigating the impacts of anthropogenic noise on beaked whales, particularly activities that transmit sounds into the water column. These studies have, in part, been driven by mass strandings of beaked whales coinciding temporally and spatially with naval manoeuvres (MacLeod & D'Amico 2006). For example, necropsies (autopsies) of stranded Blainville and Cuvier's Beaked Whales following low frequency acoustic sonar tests have revealed tissue trauma associated with an acoustic or impulse injury that caused the animals to strand (Frantzis 1998). It has been noted that groups composed primarily of immature, juvenile or cow-calf pairs may be more susceptible to strandings associated with anthropogenic noise, although it is not known why this might be the case. Anthropogenic sounds may disrupt or interfere with the sounds produced by beaked whales, including disruption of navigation, and/or interfere with social communication. While data is limited, where there is data, beaked whales appear to use relatively high frequency echolocation (up to 120 kHz or more) and non-echolocation sounds in the region of one to 16 kHz (MacLeod & D'Amico 2006).
Although little is known about reproduction in beaked whales, it is likely that Arnoux's Beaked Whale have a low reproductive rate, producing one offspring every two to three years. This means that population recovery is likely to be a slow process.
Bannister and colleagues (1996) and Ross (2006) recommended the following measures be taken to better understand the threats to Arnoux's Beaked Whale:
- Determine the distribution and monitor abundance of Arnoux's Beaked 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, particularly in southern waters.
- Obtain information on Arnoux's Beaked Whale diet to determine their trophic level and assess any possible impact of the fishing industry on dolphin food resources.
- Obtain basic biological information (including diet and pollutant levels) from incidentally-caught and stranded Arnoux's Beaked Whale specimens, and make specimens available to appropriate scientific museums to enable collection of life history data and tissue samples for genetic analysis.
- Ensure adequate protection of species and resources in Australian and nearby waters.
Current projects initiated to address these threats include a requirement to report all incidental catches made within the Australian Exclusive Economic Zone. Disentanglement workshops have also been initiated, particularly for offshore fisheries (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 (Department of the Environment and Heritage 2005c) have been prepared.
No threats data available.
Balcomb, K.C. (1989). Baird's Beaked Whale Berardius bairdii Stejnegeri, 1833: Arnoux's Beaked Whale Berardius arnuxii Duvernoy, 1851. In: Ridgway, S.H. & R. Harrison, eds. Handbook of Marine Mammals Vol. 4: River Dolphins and the Larger Toothed Whales. Page(s) 261-288.
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/resource/action-plan-australian-cetaceans.
Brownell, R.L. (1974). Small Odontocetes of the Antarctic. In: Antarctic Mammals. 18:19.
Dalebout, M.L. (2002). Species identity, genetic diversity and molecular systematic relationships among the Ziphiidae (beaked whales). Ph.D. Thesis. University of Auckland, New Zealand.
Department of the Environment and Heritage (2005e). Australian National Guidelines for Whale and Dolphin Watching. [Online]. Available from: http://www.environment.gov.au/resource/australian-national-guidelines-whale-and-dolphin-watching-2005.
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.
Frantzis, A. (1998). Does acoustic testing strand whales?. Nature. 392:29.
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.
MacLeod, C.D. & A. D'Amico (2006). A review of beaked whale behaviour and ecology in relation to assessing and mitigating impacts of anthropogenic noise. Journal of Cetacean Research and Management. 7(3):211-221.
Paterson, R.A. & R.E. Parker (1994). Aerial observations of large ziphiid whales, possibly Berardius arnuxii, off the southern coast of New South Wales. Memoirs of the Queensland Museum. 37:301-306.
Peddemors, V.M. (2006). Personal Communications. Sydney: Graduate School of the Environment, Macquarie University.
Peddemors, V.M. (2006b). Personal Observations. Graduate School of the Environment, Macquarie University, Sydney.
Peddemors, V.M. & R. Harcourt (2006). Personal Communication. Sydney: Graduate School of the Environment, Macquarie University.
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. (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/resource/review-conservation-status-australias-smaller-whales-and-dolphins.
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 (2014). Berardius arnuxii in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Thu, 24 Apr 2014 22:28:09 +1000.