Baird's beaked whale
Baird's beaked whale (scientific name: Berardius bairdii ) is is one of 21 species of beaked whales (Hyperoodontidae or Ziphiidae), medium-sized whales with distinctive, long and narrow beaks and dorsal fins set far back on their bodies. They are marine mammals within the order of cetaceans.
Baird's beaked whale is very closely related to Arnouxs beaked whale, the other member of the genus Berardius. In fact, some reserach have suggested that they are the same species with differences in size and range. However, analysis of "mitochondrial and nuclear intron sequence data has however revealed multiple fixed genetic differences, confirming that these species are reproductively isolated and valid taxonomic entities (Dalebout 2002)." (IUCN)
Baird’s beaked whale is the longest species of the Ziphiidae, which is a family of medium-sized whales. The name "beaked whale" comes from the way the long snout, or rostrum, tapers to a tip. From above, the rostrum looks like the neck of a bottle, and another common name for the species is giant bottlenose whale.
Berardius has four teeth in the lower jaw. Two of the teeth project from the jaw and may be used for fighting: it is common for the skin of both males and females to be heavily covered in tooth-scars all over the body.
The whales feed in deep water, diving for as long as an hour at a time to eat squid, octopus, skates, and other species that are found 2000 m below the surface.
Fifty or more whales often travel together, occasionally breaching and slapping their flippers.
They are medium to large sized whales and often grouped with the great whales. They are the largest of the Ziphiidae family, with body mass of up to 14,200 kilograms.
The average length of Baird's beaked whale is 10.3 meters for males and 11.2 meters for females, with maximum lengths of 11.9 and 12.8 meters for males and females respectively. Calves are about 4.5 meters at birth.
Their bodies are long and cylindrical with a characteristic beak where the lower jaw extends about 10 centimeters beyond the tip of the the upper jaw. Their blow hole is low and wide. Their heads are angled backwards when they breathe so that their front teeth and beaks are visible (Minasian et al. 1984; Watson 1981).
Baird's beaked whales have two pairs of teeth, the first pair protruding nine centimetres from the extended lower jaw. The second pair is roughly 20 centimetres behind the first and grow to about five centimetres. The teeth of the female are slightly smaller than those of the male.
Baird's beaked whale are a blueish grey color, often with a brown tinge. Their undersides are usually lighter with three patches of white on the throat, between the flippers, and near the navel and anus. These spots range in size from barely visible to an almost continuous stripe across the belly. Two grooves run along the underside of the jaw in a wishbone shape. Females tend to be lighter in color than males, who often have tooth scars on their beaks.
Berardius bairdii have trangular fins about 30 centimeters tall and set far back on the body (Minasian et al. 1984, Watson 1981). (Minasian et al., 1984; Watson, 1981)
Overview physical features are: endothermic; homoiothermic; bilateral symmetry.
Key species behaviours are: natatorial; motile; social; dominance hierarchies. Baird's beaked whales travel in small groups ranging from six to thirty members. These breeding groups are led by one large male. The scars on the beaks and backs of males suggest aggression and rivalry for this leadership position (Watson, L. 1981).
They usually rise three to four times at 10-20 second intervals before diving for 20 minutes or longer. They have been known to stay underwater for over an hour. These whales are fairly elusive and shy of ships, though they sometimes bask at the surface until startled (Watson, L. 1981).
Baird's beaked whales have natural parasites such as ship barnacles, acorn barnacles, and whale lice. Oval sucker scars caused by parasite crustaceans (Livoneca ravnaudi) can be seen on many individuals. They are sometimes found stranded (Watson, L. 1981).
The average lifespan is about 70 years, with a maximum recorded lifespan in the wild of 84 years. These animals reach sexual maturity in about 10 years but they only reach physical maturity after about 20 years (Ronald Nowak 1999).
Most Baird's beaked whales reach sexual maturity when they are about 9.4 meters long for males and 10 meters long for females. They mate in mid-summer in warm waters near Japan and California.
The gestation period is thought to be approximately ten months, though pregnancies of up to 17 months have been reported. Calves are born between late November and early May. A mother will usually produce one calf every three years. (Minasian,S.,K Balcomb, III and L Foster, 1984. Watson, L. 1981).
Key Reproductive Features: Iteroparous; Seasonal breeding; Gonochoric/gonochoristic/dioecious (sexes separate); Sexual; Viviparous
Distribution and Movements
Baird's beaked whales have a limited range within the northern Pacific ocean. They can be found in waters near Japan and southern California and as far north as the Bering Sea. They prefer deeper water, beyond the 1000 meter line (Minasian, S.,K Balcomb, III and L Foster, 1984. Watson, L. 1981).
From June to August, Baird's beaked whaless can be found in warm waters near Japan and California and near British Columbia in September.
In the fall, the whales migrate north towards the Bering Sea and spend their winters in cold water near the Aleutian islands. This may be due to seasonal distribution of squid. They prefer deep water, beyond the 1000 meter line (Minasian,S.,K Balcomb, III and L Foster, 1984. Watson, L. 1981).
These whales are deep divers and feed most often on squid, particularly Gonatus fabricii. They also consume mollusks, octopus, lobster, crab, rockfish, and herring. Occasionally they eat starfish and sea cucumbers (Watson, L. 1981).
Killer whales (Orcinus orca) occasionally prey on Baird's beaked whales.
Economic Importance for Humans
These whales have been a long time resource for Japanese coastal whaling industries. In the 1950's, due to new fishing technologies, up to 382 whales were taken each year. With declining numbers and emphasis on other species, the number of Berardius bairdii caught has diminished (Watson, L. 1981).
Threats and Conservation Status
The IUCN Red List notes:
Three subpopulations of Baird’s beaked whales are recognized in the western North Pacific (Sea of Japan, Okhotsk Sea, and Pacific Ocean), where these whales have been exploited for centuries. There are an estimated 1100 Baird’s beaked whales in the eastern North Pacific, including about 228 (CV=51%) off the US west coast (Barlow et al. 2006, Caretta et al. 2006). Abundance in Japanese waters has been estimated at about 7,000 individuals (5,029 off the Pacific coast, 1260 in the eastern Sea of Japan, and 660 for the southern Okhotsk Sea – Miyashita 1986; Kasuya 2002; Barlow et al. 2006). These are likely underestimates because visual survey methods often do not account for the fact that the whales dive for long periods and are inconspicuous when they surface (Barlow 1999). There is no information on trends in the global abundance of this species.
Baird’s beaked whales are one of the few species of ziphiids to be commercially hunted (Kasuya 2002; Kasuya and Ohsumi 1984). Small numbers have been hunted by the Soviets, Canadians and Americans, whereas hunts by Japan have been major. The Japanese fishery started in the early 1600s and underwent several expansions and declines. At its peak, after World War II, over 300 whales were killed annually. Now the industry operates with a quota of 8 for the Sea of Japan, 2 for the southern Okhotsk Sea and 52 for the Pacific coasts (Kasuya 2002).
Incidental catches have been recorded, but are generally not common. Some Baird's beaked whales have been caught in Japanese salmon driftnets (Reeves and Mitchell 1993).
This species, like other beaked whales, is likely to be vulnerable to loud anthropogenic sounds, such as those generated by navy sonar and seismic exploration (Cox et al. 2006)
There has been no agreement in the IWC on whether or not it has the competence to classify or set catch limits for this species, even though it is included in the IWC definition of "bottlenose whale" (the only species so regulated is the northern bottlenose whale, Hyperoodon ampullatus). At the 2000 annual meeting of the IWC Scientific Committee, Japan explicitly expressed its unwillingness to subject its research and management program for this species to international scrutiny (IWC 2001).
Although the IWC does not control the annual quota of Baird's beaked whales, some assume that the present catch levels over a short period would not affect the subpopulation, but research is needed to obtain information that will allow a full assessment of its status. The species is listed on CITES Appendix I.
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