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|
|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||Mesoplodon grayi |
|Species author||von Haast,1876|
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: Mesoplodon grayi
Common name: Gray's Beaked Whale
Other names: Scamperdown Whale, small-toothed whale
Gray's Beaked Whale was first described by the New Zealand Museum Director, Julius von Haast in 1876 and named after the British biologist, John Gray, who had died the year before (Martin 1990). No subspecies are recognised (Rice 1998).
Adult Gray's Beaked Whales are dark grey, with pale patches on the belly and uro-genital area (Jefferson et al. 1993). Anterior to the blowhole the melon and proximal (front) section of the beak are light-grey, while the distal end of the beak and upper 'lips' are white (Dalebout et al. 2004). The lower jaw can be several centimetres longer than the upper jaw and the protruding portion is white (Dalebout et al. 2004). The head is small, and the narrow beak has a straight mouthline. In males a small triangular tooth erupts from either side around the middle of the lower jaw (Ross 2006). Both sexes have 1722 pairs of small, slim, conical vestigial teeth towards the rear of each upper jaw which are shallow-rooted and apparently of little functional use (Ross 2006). The dorsal fin of Gray's Beaked Whales is pointed with a concave trailing edge, the flippers are short and broad, and the tail flukes are broad and almost straight edged with the tips pointing slighting backwards (Shirihai 2002).
Gray's Beaked Whales exhibit sexual dimorphism, with females generally being larger than males (Martin 1990). The individual measured 5.64 m (unknown sex, possibly female) and the longest male measured 4.74 m (1075 kg) (MacLeod 2006; Martin 1990). Ross (1984) estimated the maximum weight of Gray's Beaked Whale would be about 1.5 tonnes, but few specimens have been weighed.
Gray's Beaked Whales usually occur singly, but groups of two to six individuals have been observed (Shirihai 2002). Mass strandings in beaked whales are unusual, but at least four such events have been recoded on Chatham Island, New Zealand (Baker 1990, Dalebout 2002), including one in 1874 involving approximately 25 animals from which this species was initially described (Dalebout et al. 2004). These events suggest that there may be some social cohesion in Gray's Beaked Whale (Martin 1990).
Gray's Beaked Whale is known from 48 strandings along the Australian coast, including 16 from southern Western Australia, eight from South Australia, three from Victoria, 14 from Tasmania, and seven from NSW (Bannister et al. 1996; DEW 2007h; Kemper & Ling 1991; McManus et al. 1984). This species is the second most commonly stranded beaked whale in Australia (48 events) after the Strap-toothed Beaked Whale (M. layardii) (63 events).
The current extent of occurrence for Gray's Beaked Whale is estimated to be greater than 20 000 km² (based on the Australian EEZ (200 nm, between approximately 30° S and 50° S, and 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 30° S.
The area of occupancy of Gray's Beaked Whale is estimated 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 of this species, potentially depleting local populations and leading to a decrease in area of occupancy.
Gray's Beaked Whales are considered to occur in one location as deep water is not thought to be a barrier to movement in the species.
Gray's Beaked Whale is distributed circumglobally in temperate waters of the Southern Hemisphere. The distribution is known from specimens recorded from Argentina, Chile, South Africa, New Zealand and Australia, and by sightings in the Indian Ocean (Gambell et al. 1975) to latitudes as low as 25° S south of Madagascar (Ross 2006). Gray's Beaked Whale is known from the Northern Hemisphere only through only one stranding in the Netherlands in 1927, presumably an anomalous vagrant (Martin 1990; Ross 2006).
It is unlikely that Australian Gray's Beaked Whales represent a distinct population, as no subspecies are currently recognized (Dalebout et al. 2002; Rice 1998). As the Gray'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, Gray's Beaked Whale is not well surveyed. Their distribution is primarily assumed from incidental sightings, plus beach-cast animals, for all areas.
Gray's Beaked Whales 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 three nautical mile state waters limit out to the boundary of the EEZ (200 nautical miles and further in some places). Gray's Beaked Whale is also subject to International Whaling Commission (IWC) regulations and protected within the Indian Ocean Sanctuary and Southern Ocean Sanctuary.
Gray's Beaked Whales are found in deep oceanic waters of temperate (1020 °C) to subantarctic (18 °C) regions (Pittman 2002; Ross 2006). No information on habitat is available, although these whales are presumed to feed at depth on mid- and deep-water squid (MacLeod et al. 2003; Pitman 2002). Shipboard surveys of beaked whales (Mesoplodon spp. and Ziphius cavirostris) from 19911998 along the shelf edge and Gulf Stream waters off the north-east United States showed that these species frequent similar shelf-edge habitats (Waring et al. 2001). Beaked whales were present mostly along the colder shelf edge and associated significantly with canyon habitats (Waring et al. 2001). However, a more recent survey of the same area found that this previously proposed definition of beaked whale habitat may be too narrow, as suggested that beaked whales may be found from the continental slope to the abyssal plain, in waters ranging from well-mixed to highly stratified (Ferguson et al. 2006). It is likely that such habitats are utilised by beaked whales along much of Australia's extensive coastline, particularly along the more southern shores that support populations of Andrews' Beaked Whale (Ross 2006).
As for many species of beaked whale, Gray's Beaked Whale may also be found close to undersea features such as submarine escarpments and sea mounts where prey are believed to aggregate (Balcomb 1989). Although no information is available on whether Gray's Beaked Whale uses different habitats for different activities, the majority of strandings in Australia occur from December to April, indicating a seasonal influx during summer (Bannister et al. 1996). The presence of many mature females with calves in these summer strandings suggests that Gray's Beaked Whales may use waters over the continental shelf for breeding & calving purposes. However, the lack of sightings implies they do not normally come close to shore (Dalebout et al. 2004). In the eastern tropical Pacific, beaked whales were sighted an average of 1000 km offshore, with a range of approximately 403750 km. The mean water depth of Mesoplodon beaked whale sightings in this region was just over 3.5 km, with a maximum depth of approximately 5.75 km (Ferguson et al. 2006).
Sexual maturity in Gray's Beaked Whales is reached at about 4.5 m (Ross 2006), but other life history characteristics are otherwise largely unknown. The maximum recorded age for Baird's Beaked Whale (Berardius bairdii) is 84 years, and for all other beaked whales recorded age is between 27 and 39 (Mead 1984, in MacLeod & D'Amico 2006). Natural causes of mortality in beaked whales are poorly understood, but are thought to include predation, disease and effects associated with 'old age' (MacLeod & D'Amico 2006). In particular, severe osteomyelitis has been noted in aged, stranded specimens, possibly contributing to death (Bannister et al. 1996).
Breeding areas and habitat are unknown for Gray's Beaked Whales, but stranding data suggest these may be in shallower water over the continental shelf from late spring through summer (Baker 1999; Dalebout et al. 2004). This seasonal inshore movement could subject the species to higher threat levels due to ship collisions. Little is known about the mating system of this species, but scarring on both females and males suggest that there may be extensive physical competition among males for mates. The gestation period for Gray's Beaked Whales is unknown, but calves are born from summer through autumn (Ross 2006). Length at birth is about 2.1 m, calves weaning at about 3.6 m one year later (Ross 2006).
The slow reproductive capacity of Gray's Beaked Whale, with a calving interval of at least three to four years, leads to slow population growth and could limit the species' capacity to recover from threatening processes.
Examination of stomach contents from stranded beaked whales indicates that these animals feed primarily on deep-water cephalopods (e.g. Histioteuthis spp., Taonis spp. and Gonatus spp.) with most prey caught at depths of 200 m or more (Macleod et al. 2003; Pitman 2002).
Gray's Beaked Whales are active predators and presumed to be strong swimmers capable of deep dives in pursuit of prey, but the mode of capture is not known. Only adult males have erupted teeth, consisting of a single pair of massive teeth near the middle of the lower jaw, possibly used in mating interactions. It thus seems unlikely that these teeth are used for prey capture, but rather that prey are seized and disabled between the hard edges of the mandibles and the rostral palate (Ross 2006). The pair of V-shaped throat grooves typical of this Family may enable distension of the throat, creating a sucking pressure and allowing larger whole prey to be swallowed whole (Baker 1990; Pitman 2002).
The majority of Gray's Beaked Whale strandings in Australia have occured from December to April, suggesting a seasonal movement inshore (and possibly to lower latitudes) (Ross 2006). A similar increase in Gray's Beaked Whale summer strandings has been reported for New Zealand (Baker 1999). As many of these summer strandings consist of mature females with calves, it has been suggested that there may be a seasonal movement of pregnant females to lower latitudes to give birth (Bannister et al. 1996).
Like other beaked whales, Gray's Beaked Whale is difficult to identify at sea. Generally, the initial sighting cue for Gray's Beaked Whale is a glimpse of a back or body (Dalebout et al. 2004), but this species occasionally does breach and may porpoise in low arc-shaped leaps (Shirihai 2002). The small head and extremely long narrow beak allow identification of Gray's Beaked Whales, but the most distinctive feature is the white colouration of the beak which is raised above the water surface as the animal rolls through its breathing movement (Dalebout et al. 2004). In mature males the small triangular tusk just forward of midway along the lower jaw is also distinctive.
Gray's Beaked Whales do not produce a 'blow' when breathing, generally respiring between three to five times before diving (Dalebout et al. 2004). In addition, they, like other beaked whales, spend much of their time at depth, surface without a visible splash, and are relatively silent when they are within 200 m of the surface (Ferguson et al. 2006). Whilst at the surface, they are slow moving (Jefferson et al. 1993; Pitman 2002).
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 temperate Australian waters, but surveys conducted en route to the Antarctic have covered substantial portions of potential range of Gray's Beaked Whales. Unfortunately, much of this range is in areas experiencing few calm days, leading to difficulty in sighting beaked whales. During non-dedicated surveys such as these, a minimum requirement should be 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 (Peddemors 2006, pers. comm.).
Although there has never been a directed fishery targeting Gray's Beaked Whale, some beaked whales are occasionally taken by opportunistic whalers (Pitman 2002). Incidental entanglement in gillnets continues to be a potential threat (Reeves et al. 2003), as is collision with vessels (Dalebout et al. 2004). Investigations of incidental captures in the pelagic drift gillnet fishery off the north-east United States coast indicated that 46 fishery related mortalities of beaked whales occurred between 1989 and 1998, 24 of which were Sowerby's Beaked Whales (M. bidens), four were True's Beaked Whales (M. mirus) and 17 were unidentified beaked whales (Waring et al. 2001). This highlights the danger of entanglement in drift nets and other nets set, lost or discarded in international waters, and suggests incidental mortality in fishing gear should be considered as a current and potentially increasing threat to Gray's Beaked Whales (Bannister et al. 1996; Reeves et al. 2003; 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). Autopsies of stranded Blainville's and Cuvier's Beaked Whales following low frequency acoustic sonar tests have revealed tissue trauma and was attributed to an acoustic or impulse injuries causing the animals to strand (Frantzis 1998). It has been noted that beaked whales with group sizes of less than 20 (including the Mesoplodon spp.), and particularly 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. 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 116 kHz (MacLeod & D'Amico 2006).
It is likely that Gray's Beaked Whales have a low reproductive rate, producing one offspring every three to four years. This means that population recovery is a slow process.
Bannister and colleagues (1996) and Ross (2006) recommended the following actions be taken to better understand the threats to Gray's Beaked Whale:
- Determine the distribution and monitor abundance of Gray'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 sub-Antarctic and cold temperate waters.
- Obtain information on Gray's Beaked Whale diet to determine their trophic level and assess any possible impact of the fishing industry on beaked whale food resources.
- Obtain basic biological information (including diet, pollutant levels and genetic samples) from incidentally-caught and stranded animals, and ensuring specimens are made 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.
Disentanglement workshops have also been recommended, particularly for offshore fishers, and suitable action plans developed (Bannister et al. 1996).
Current projects initiated to address these threats include a requirement to report all incidental catches made within the Australian EEZ (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 (DEWHA 2007h), and Australian National Guidelines for Whale and Dolphin Watching (DEH 2005c) have been published.
No threats data available.
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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/coasts/publications/cetaceans-action-plan/pubs/whaleplan.pdf.
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Department of the Environment and Heritage (2005e). Australian National Guidelines for Whale and Dolphin Watching. [Online]. Available from: http://www.environment.gov.au/coasts/publications/whale-watching-guidelines-2005.html.
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.
Ferguson, M.C., J. Barlow, B. Reilly, S.B. & T. Gerrodette (2006). Predicting Cuvier's (Ziphius cavirostris) and Mesoplodon beaked whale population density from habitat characteristics in the Eastern Tropical Pacific Ocean. Journal of Cetacean Research and Management. 7(3):287-299.
Frantzis, A. (1998). Does acoustic testing strand whales?. Nature. 392:29.
Gambell, R, P.B.Best, & D.W.Rice (1975). Report on the International Indian Ocean Whale marking cruise, 24 November 1973-3 February 1974. Report of the International Whaling Commission. 25:240-252.
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].
Kemper, C.M. & J.K. Ling (1991). Whale Strandings in South Australia (1881-1989). Transactions of the Royal Society of South Australia. 115:37-52.
MacLeod, C.D. (2006). How big is a beaked whale? A review of body length and sexual size dimorphism in the family Ziphiidae. Journal of Cetacean Research and Management. 7(3):301-308.
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.
MacLeod, C.D., M.B. Santos & G.J. Pierce (2003). Review of data on diets of beaked whales: Evidence of niche separation and geographic segregation. Journal of the Marine Biological Association of the United Kingdom. 83:651-665.
Martin, A.R. (1990). Whales and Dolphins. London, UK: Salamander Books Ltd.
McManus, T.J., J.E. Wapstra, E.R. Guiler, B.L.Munday & D.L. Obendorf (1984). Cetacean Strandings in Tasmania from February 1978 to May 1983. Papers and Proceedings of the Royal Society of Tasmania. 118:117-135.
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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.
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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.
Shirihai, H. (2002). The Complete Guide to Antarctic Wildlife. Princeton & Oxford: Princeton University Press.
Waring, G.T., J.M. Quintal & S.L. Swartz (2001). U.S. Atlantic and Gulf of Mexico marine mammal stock assessments - 2001. NOAA Technical Memorandum. NMFS-NE168.
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). Mesoplodon grayi in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 6 Dec 2013 02:58:20 +1100.