Berardius bairdii, Stejneger, 1883
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publication ID |
https://doi.org/ 10.5281/zenodo.6608481 |
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DOI |
https://doi.org/10.5281/zenodo.6608491 |
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persistent identifier |
https://treatment.plazi.org/id/035387C7-FFC5-FFAB-FF7A-15ABFEDEF3A5 |
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treatment provided by |
Diego |
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scientific name |
Berardius bairdii |
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Baird’s Beaked Whale
French: Baleine-a-bec de Baird / German: Baird-Schnabelwal / Spanish: Zifio de Baird
Other common names: Giant Bottle-nosed Whale, North Pacific Bottlenose Whale, Northern Fourtoothed Whale
Taxonomy. Berardius bairdii Stejneger, 1883 ,
Russia, Commander Islands, “found stranded in Stare Gavan, on the eastern shore of Bering Island.”
This species is monotypic.
Distribution. Cooler waters of the N Pacific Ocean, N limit apparently determined by the relatively shallow waters of the Bering Sea and recorded S to La Paz in Baja California, Mexico (E Pacific Ocean), and S Japan (W Pacific Ocean). The S limit in central N Pacific Ocean remains unclear. View Figure
Descriptive notes. Total length 1000-1200 cm; weight 10,000-12,000 kg. Female Baird’s Beaked Whales may be slightly larger than males, but there is no clear evidence of any major sexual dimorphism. Body is spindle-shaped, with greatest girth around its midpoint. Flukes are wide in relation to body length, and tailstock is compressed laterally. Dorsal fin is small and set approximately two-thirds of the distance between tip of the beak and end of the tail. Coloration is typically dark brown, dark gray, or black; however, bodies of some individuals, especially older ones, can be covered in white linear scars from intraspecific aggression or pale oval scars from attacks by cookiecutter sharks (Isistius spp.). Rostrum and lower jaw form a moderately long beak that is clearly distinct from the melon. Adults have two pairs oftusks in the lower jaw; front pair is larger. Unlike many other species of beaked whales, tusks of Baird's Beaked Whales emerge to become functional in adult males and females. These tusks can become heavily worn in older individuals.
Habitat. Restricted to deeper oceanic waters,typically greater than 1000 m in depth. Nevertheless, there is evidence that Baird’s Beaked Whales move into shallower waters around Japan in summer months.
Food and Feeding. Baird's Beaked Whales consume a range of deep-water squid and deep-waterfish. They are known to consume benthic, bentho-pelagic, and pelagic species, and they may feed at depths of up to 3000 m. Individual foraging dives lasting ¢.30 minutes are common and some may last over an hour.
Breeding. Baird's Beaked Whales become sexually mature at c.10 years of age and physically mature at ¢.20 years. Some individuals may live as long as 80 years. Gestation is thought to be ¢.17 months, after which the female gives birth to a single young. Lactation may last several years. Nothing is known ofthe courtship behavior of Baird's Beaked Whale, but linear scars caused by tusks of conspecifics indicate that at least some interactions between individuals are aggressive.
Activity patterns. There is no specific information available for this species, but if, as is the case in other species of beaked whales, it consumes relatively small prey, it is likely that individuals have to spend a large proportion (60-70%) of their time foraging at great depth.
Movements, Home range and Social organization. There is no specific information available for this species, but these whales occur in larger groups than most species of beaked whales, and there may be as many as 100 individuals in the largest groups. Groups are likely to contain multiple adult males and females, as well as dependent offspring. Nothing is known about possible substructuring within these groups.
Status and Conservation. CITES Appendix I. Classified as Data Deficient on The [UCN Red List. There are no estimates of global population size of Baird's Beaked Whales. In the waters around Japan, it has been estimated that there may be ¢.7000 individuals. Estimates for the eastern North Pacific are ¢.1100 individuals. In general, beaked whales are difficult to detect, and it is likely that the techniques used to calculate these values underestimate the actual population size of Baird's Beaked Whales. In the past, the main conservation issue for Baird’s Beaked Whale was whaling, particularly in Japanese waters, and a small number of individuals are still taken each year. Baird’s Beaked Whale may be at risk of bycatch and impacts associated with anthropogenic noise, but these do not now appearto represent a major threat to its conservation status. As a species restricted to cooler waters with a limited ability to shift its distribution northward in response to changes in water temperature (because of the shallow waters of the Bering Sea), Baird's Beaked Whale may be at risk of distributional contractions due to climate change, but the likelihood, extent, and conservation implications of such changes remains unknown.
Bibliography. Balcomb (1989), Macleod (2006, 2009), MacLeod & D’Amico (2006), MacLeod et al. (2006), Rice (1998).
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