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A comparison between the northern bottle nosed whale and the southern bottle nosed whale

Hyperoodon planifrons Common name: No subspecies are recognised Rice 1998. The name planifrons, meaning 'level browed', was given to this species because the summits of the crests, or shields, on the upper jaw are much lower than those of the Northern Bottlenose Whale, Hyperoodon ampullatus Martin 1990. Genetic analyses show clearly that these taxa are distinct and markedly divergent species, which may well have been separated for five million years.

The Southern Bottlenose Whale has a higher genetic diversity compared with its northern counterpart, perhaps a result of the intense fishery for H. Top Southern Bottlenose Whales are relatively large beaked whales, reaching a maximum of 7. Their body shape is robust and they have a large, bulbous-shaped forehead and a short, dolphin-like beak. The rear half of the mouth-line curves upward and there is a pair of grooves on the throat, typical of beaked whales Martin 1990.

Southern Bottlenose Whales have a falcate sickle-shaped dorsal fin that is set well behind the middle of the back. The colour of Southern Bottlenose Whales is chocolate brown to yellow, being lighter on the flanks and belly. This coloration is believed to be caused by a thin layer of phytoplankton diatoms living on the whales' skin Culik 2003. 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 1999.

The broad tail flukes are un-notched and deeply concave, while the flippers are small and tapered Shirihai 2002. Top The relatively few strandings of Southern Bottlenose Whales are recorded mainly in New Zealand, but at least 14 have occurred in Australia: This species is thought to rarely venture into continental seas. The area of occupancy of the Southern Bottlenose Whale cannot be calculated due to the paucity of records for Australia.

Future expansion of high-seas pelagic gillnet fisheries may result in increased incidental catches, potentially depleting local waters and leading to a decrease in area of occupancy. As such, no distribution fragmentation is anticipated for the Southern Bottlenose Whale in Australian oceanic Antarctic, sub-Antarctic and cold temperate waters.

Species Profile and Threats Database

There are no estimates of Southern Bottlenose Whale population size, either globally or for Australia, so the proportion of the global population in Australian waters is unknown. It is unlikely that Australian Southern Bottlenose Whales are a distinct population, as no subspecies are currently recognised Rice 1998.

Top World-wide, Southern Bottlenose Whales are not well surveyed. Their distribution is primarily assumed from limited incidental sightings, plus beach-cast animals, for all areas other than the Antarctic where whale surveys have been conducted.

  • Hyperoodon planifrons Common name;
  • The back is light-to-mid grey;
  • Based on the topography and bathymetry of the shoreline in southeastern Brazil, this sighting must be considered an unusual record;
  • Mating in Southern Bottlenose Whales may occur in summer and calves are born in spring-early summer, after a gestation period of about 12 months as for H;
  • The major prey item is deep-water squid and dives of over 1,400m have been recorded with animals submerged for up to 2 hours at a time;
  • Retrieved 12 January 2018.

However, these methods are believed to result in reliable distributional information for this species. Top No population size is known, although the Southern Bottlenose Whale is not considered abundant as sightings and strandings are rare. No key localities are known for Southern Bottlenose Whales in Australia. There appears to be some stock differentiation in the Northern Bottlenose Whale between geographic areas within the north-west Atlantic Dalebout et al.

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Until further information is available, all populations should be considered important for the species' long-term survival and recovery to ensure genetic fitness and potential emigration of individuals into populations negatively affected through threatening processes. The Sanctuary includes all Commonwealth waters from the three nautical mile State waters limit out to the boundary of the EEZ out to 200 nm and further in some places. Top Southern Bottlenose Whales are considered an oceanic species.

Sightings of Southern Bottlenose Whales near the Antarctic ice edge have only been made in summer, but this may be biased through seasonal survey effort SOCEP unpublished data. No information is available on whether this beaked whale uses different habitats for different activities.

Top Life history data for the Southern Bottlenose Whale are extremely limited, and information provided in this profile draws on data from southern African, Australian and New Zealand specimens, as well as comparisons with the Northern Bottlenose Whale H. Sexual maturity for Southern Bottlenose Whales is estimated to be attained at nine to 11 years as for H. Male Northern Bottlenose Whales are thought to live for more than 50 years, and the age of females exceeds 37 years.

Similar maximum ages are likely for Southern Bottlenose Whales. A young male Southern Bottlenose Whale specimen from Victoria carried whale lice Platycyamus thompsoni and scars, possibly from bites by the small shark Isistius sp.

The specimen also bore recent tooth rakes possibly caused by a Killer Whale Dixon et al. Both the Northern and Southern Bottlenose Whales exhibit care-giving behaviour for their calves, possibly a defence against attacks by Killer Whales.

Extremely limited reproductive information is available for the Southern Bottlenose Whale.

  • Faroese regulations only allow the killing of bottlenose whales which have beached themselves and cannot be driven out again;
  • If the same patterns observed for H;
  • They are not thought to be highly migratory in nature and in some areas where they have been well-studied, e;
  • The occurrence of the southern bottle-nosed whale in Tasmanian waters;
  • Whales, Dolphins and Porpoises Carwardine, 1995;
  • If seasonal latitudinal movements of southern bottlenose whales effectively occur and they spend considerable time in distinct areas of the ocean basins, another important ecological role as vertical and horizontal vectors for nutrients should be attributed to these ziphiids see ROMAN et al.

Mating in Southern Bottlenose Whales may occur in summer and calves are born in spring-early summer, after a gestation period of about 12 months as for H. No calving areas are known for Australian waters Bannister et al. The calving interval for Southern Bottlenose Whales is unknown, but in beaked whales it is expected to be one calf every few years, leading to a slow reproductive capacity. Top Stomachs of Southern Bottlenose Whale specimens from Antarctic and Subantarctic waters contained the remains of squid and some krill Euphausia superbathe latter possibly ingested incidentally with normal prey items Bannister et al.

The stomach of one South Australian specimen contained a large quantity of squid beaks possibly Polypus variolatus ; the intestine of one South African specimen contained four cephalopod beaks Bannister et al. The stomach of a dependent or recently weaned juvenile from Victoria contained the tunicates Pyrosoma atlantica and Thetys vagina. The stomach contents of an adult male stranded in NSW included numerous beaks from large onychoteuthid squids, other families of cephalopods and numerous large tunicates, providing evidence of deep diving for prey G.

Ross 2006, personal observation. Stomach contents from a female stranded on Heard Island contained both Antarctic south of the Antarctic polar front and subantarctic south of the subtropical convergence cephalopod species. Patagonian toothfish skeletal material was also present Slip et al.

Blubber samples taken from Northern Bottlenose Whales off Newfoundland show that the species feeds mainly on squid of the genus Gonatus Hooker et al.

  • These impacts on beaked whales must be monitored in order to evaluate their magnitude for future management plans;
  • Their distribution is primarily assumed from limited incidental sightings, plus beach-cast animals, for all areas other than the Antarctic where whale surveys have been conducted;
  • If seasonal latitudinal movements of southern bottlenose whales effectively occur and they spend considerable time in distinct areas of the ocean basins, another important ecological role as vertical and horizontal vectors for nutrients should be attributed to these ziphiids see ROMAN et al;
  • Top Stomachs of Southern Bottlenose Whale specimens from Antarctic and Subantarctic waters contained the remains of squid and some krill Euphausia superba , the latter possibly ingested incidentally with normal prey items Bannister et al.

Stones, fish-netting and plastic bags have also been found in stomachs. Only adult male Southern Bottlenose Whales have functional teeth, comprising a single pair located at the tip of the lower jaw.

They appear to be used as weapons in agonistic encounters, leading to heavy scarring of older animals. The massive forehead melon of Southern Bottlenose Whales may be used to concentrate bursts of high-energy sound to acoustically stun prey Bannister et al.

As Southern Bottlenose Whales lack functional gripping teeth, prey may be seized and disabled using the hard edges of the mouth parts before being swallowed Bannister et al. The presence of plastic bags in the stomachs of Bottlenose Whales is of concern, as the apparent feeding habit of sucking in prey, in conjunction with increasing levels of plastic pollution in the oceans, would inevitably result in an increased chance of Southern Bottlenose Whales ingesting plastic and exposing themselves to a threatening process.