Berardius
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The four-toothed whales or giant beaked whales are beaked whales in the genus Berardius. They include Arnoux's beaked whale (Berardius arnuxii) in cold Southern Hemispheric waters, and Baird's beaked whale (Berardius bairdii) in the cold temperate waters of the North Pacific. A third species, Sato's beaked whale (Berardius minimus), was distinguished from B. bairdii in the 2010s.<ref name=nat_name>Template:Cite journal</ref>
Arnoux's and Baird's beaked whales are so similar that researchers have debated whether or not they are simply two populations of the same species. However, genetic evidence and their wide geographical separation has led them to be classified as separate.<ref name="Dalebout" /> Lifespan estimates, based on earwax plug samples, indicate male whales can live up to 85 years, while females can have a lifespan of 54 years.<ref name=":11">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite news</ref> It is estimated that the length at birth is ~Template:Convert. Growing up to ~Template:Convert, these are the largest whales belonging to the family Ziphiidae.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Sato's beaked whale is much smaller, with adult males having a length of ~Template:Convert.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
While Berardius arnuxii and Berardius bairdii are considered least concern by the IUCN,<ref name="IUCN1">Template:Cite iucn</ref><ref name="IUCN2">Template:Cite iucn</ref> Berardius minimus is labeled as near threatened Template:As of.<ref name="IUCNminimus">Template:Cite iucn</ref>
This article currently largely treats four-toothed whales as monospecific, due to a lack of species-specific information.
Species overviewEdit
Berardius was once classified as containing only two species: Arnoux's beaked whale (Berardius arnuxii) in the Southern Hemisphere waters, and Baird's beaked whale (Berardius bairdii) in the North Pacific.<ref name=Balcomb>Template:Cite book</ref> Arnoux's beaked whale was described by Georges Louis Duvernoy in 1851. The genus name honors admiral Auguste Bérard (1796–1852), who was captain of the French corvette Le Rhin (1842–1846), which brought back the type specimen to France where Duvernoy analyzed it; the species name honors Maurice Arnoux, the ship's surgeon who found the skull of the type specimen on a beach near Akaroa, New Zealand.<ref>Beolens, Bo, Michael Watkins, and Michael Grayson. 2009. The eponym dictionary of mammals. Baltimore: Johns Hopkins University Press, p. 38, 54.</ref> Baird's beaked whale was first described by Leonhard Hess Stejneger in 1883 from a four-toothed skull he had found on Bering Island the previous year. The species is named for Spencer Fullerton Baird, a past Secretary of the Smithsonian Institution.<ref>Sharks and Whales (Carwardine et al. 2002), p. 356.</ref>
Researchers have debated over whether the northern and southern populations represent distinct species or whether they are simply geographic variants.<ref name=McCann>Template:Cite journal</ref> Several morphological characters have been suggested to distinguish them, but the validity of each has been disputed;<ref name=Kasuya>Template:Cite journal</ref><ref name=McLachlan>Template:Cite journal</ref><ref name=Slipp>Template:Cite journal</ref> currently, it seems that there are no significant skeletal or external differences between the two forms, except for the smaller size of the southern specimens known to date.<ref name=Rice>Template:Cite book</ref><ref name=Ross>Template:Cite journal</ref> The morphological similarity gave rise to the hypothesis that the populations were sympatric as recently as the last Pleistocene Ice Age, approximately 15,000 years ago,<ref name="Balcomb"/><ref name=Davies>Template:Cite journal</ref> but subsequent genetic analyses suggest otherwise.<ref name=Dalebout>Template:Cite thesis</ref> Phylogenetic analyses of the mitochondrial DNA control region (D-loop) revealed that Baird's and Arnoux's beaked whales were reciprocally monophyletic — lineages from each of the species grouped together to the exclusion of lineages from the other species. Diagnostic DNA substitutions were also found. These results are consistent with the current classification of Baird's and Arnoux's beaked whales as distinct species. Further, the degree of differentiation between the northern and southern forms of Berardius suggest that the species may already have been separated for several million years.<ref name="Dalebout"/>
It is speculated that the Baird's and Arnoux's whales separated from one another after their common ancestor separated from the kurotsuchi;<ref name=mystery/>Template:Better source however, this is not certain.<ref name=nat_name/> The Berardius sp. are deep divers that can spend long periods of time submerged below the surface of the water and thus are difficult to study.<ref name=":4">Template:Cite journal</ref><ref>Template:Cite journal</ref>
Possible speciesEdit
Sightings during whale watching tours and studies of stranded individuals suggest the possibility of another form of Berardius in the Sea of Okhotsk inclusive of the coast of northern Hokkaido especially around Shiretoko Peninsula and off Abashiri,<ref>*Kitano S., 2013. DNAで未知の鯨種に挑む－日本近海のツチクジラについて－. Cetoken Newsletter No.32. Retrieved on 26 January 2014
- Shiretoko Nature Cruise. 2013. 羅臼の海大集合！ 知床ネイチャークルーズ ニュース Template:Webarchive Retrieved 26 January 2014
- Uni Y., Koyama K., Nakagun S., Maeda M., 2014. Sighting Records of Cetaceans and Sea Birds in the Southern Okhotsk Sea, off Abashiri, Hokkaido Template:Webarchive. Bulletin of the Shiretoko Museum 36: pp.29–40. Retrieved on 30 May 2014</ref> or to Sea of Japan off Korean Peninsula and north pacific and Bering Sea off Alaska.<ref>Irish Whale and Dolphin Group, 2016, New species of beaked whale_or is it ? Template:Webarchive</ref> These whales are generally much smaller than known species (Template:Convert), darker in color, and inhabit shallow waters closer to coastal areas, enough to be trapped within fixed nets for salmon.<ref>Uni Y., Photos from Abashiri Nature Cruise Template:Webarchive</ref> Local whalers had called them "kurotsuchi" (= black Berardius)<ref>the term "tsuchi" is used for the whole genus</ref><ref name=nat_name/> or "karasu" (= ravens); it is not known whether these terms are synonyms or identify two separate species.<ref name=nat_name/> Genetic studies indicate that kurotsuchi are Berardius minimus, recognized as a distinct species in the 2010s.<ref name=nat_name/><ref name=mystery>Template:Cite news</ref>
"Bottlenose whales in the Sea of Okhotsk" had been reported since the time of the Soviet Union's whaling,<ref>Uni Y.,2006 Whales, Dolphins and Porpoises off Shiretoko Template:Webarchive. Bulletin of the Shiretoko Museum 27: pp.37-46. Retrieved on 26 January 2014</ref> and an unknown type of beaked whale resembling Baird's beaked whales having four tusks on upper and lower jaws has also been recorded by traditional whalers in Japan.<ref>T. Kasuya, 2011. イルカ―小型鯨類の保全生物学. University of Tokyo Press. Retrieved on 26 January 2014</ref> It is unknown whether these records correspond with this new form.
An unknown type of large beaked whale of similar size to fully grown Berardius bairdii have been reported to live in the Sea of Okhotsk, somewhat resembling Longman's beaked whale. The "Moore's Beach monster", an initially unidentified carcass found in 1925 on Moore's Beach on Monterey Bay, was identified by the California Academy of Sciences as a Baird's beaked whale.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite journal</ref> There have been claims that records of strandings of these whales exist along the areas within and adjacent to Tatar Strait in the 2010s.<ref>Template:Cite news</ref>
Physical descriptionEdit
The two established species, Baird's and Arnoux's beaked whales, have very similar features and would be indistinguishable at sea if they did not exist in disjoint locations.<ref name=":0">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Both whales reach similar sizes, have bulbous melons, and long prominent beaks. Their lower jaw is longer than the upper, and once sexual maturity is reached the front teeth are visible even when the mouth is fully closed.<ref name=":0"/><ref name=":1">Template:Cite news</ref><ref name=":11" /> The Baird's and Arnoux's beaked whales are the only whales in the Ziphiidae family where both sexes have erupted teeth.<ref name=":5">Template:Cite book</ref> The teeth in the Ziphiidae are presumed to be used by the males for fighting and competition for females. Ziphiidae has the most prevalent and pronounced markings caused by teeth scaring among the cetaceans.<ref name=":5" /> Front-facing teeth may be covered in barnacles after many years.<ref name=":1" />
Baird's and Arnoux's beaked whales have similarly shaped small flippers with rounded tips, and small dorsal fins that sit far back on their body.<ref name=":1" /> Adult males and females of both species pick up numerous white linear scars all over the body as they age, and these may be a rough indicator of age.<ref name=":5" /> These traits are similar in both sexes, as there is little sexual dimorphism in either species.<ref name=":0" /><ref name=":1" /> Among the observed differences in the sexes is their size: female Baird's and Arnoux giant beaked whales are slightly larger than the males.<ref name=":5" />
Although fairly similar, there exist some differences between the species. Baird's beaked whales are around Template:Convert when born, and can reach lengths of Template:Convert as adults, making them the largest members of the beaked whale family. Members of the Baird's species have fairly narrow body shapes despite their large size, and have dorsal fins that are rounded at the tips. Their coloration is fairly uniform and can range from brown to grey.<ref name=":1" /> Arnoux's beaked whales are around Template:Convert long as calves and can reach lengths up to Template:Convert as adults.<ref name=":0" /> Their bodies are not as narrow as the Baird's, and resemble a spindle. Unlike the Baird's beaked whale, Arnoux's have slightly hooked dorsal fins.<ref name=":0" /> Arnoux's beaked whales have a dark coloration that ranges from brown to orange due to a buildup of algae on its body.<ref name=":0" />
A third species, B. minimus, (known by the Japanese common name "kurotsuchi", which means "black Berardius") was formally named in 2019,<ref name="nat_name" /><ref>"tsuchi" is also used to describe the entire genus, including Arnoux's, not just Baird's as suggested by the research paper.</ref> after being distinguished in 2016, based on differences in haplotypes from mtDNA.<ref name="morin">Template:Cite journal</ref> It generally has a short beak (~4% body length). While other four-toothed whales are generally grey with scars, kurotsuchis usually have few linear scars, so that the dark, smooth skin contrasts highly with round, white scars of about 5 cm diameter (from cookiecutter shark bites).<ref name=":6" /> The tip of the rostrum is also white. The kurotsuchi is shorter than other four-toothed whales, around Template:Convert long at maturity, hence the species name, B. minimus (="smallest"). No females of this species have yet been described in the research literature.<ref name="nat_name" />
Population and distributionEdit
The total population is not known for two of the three species. Estimates for Baird's are of the order of 30,000 individuals. Nothing is known at all about the population size of the third species of Berardius, first scientifically described in the 2010s.<ref name=":6">Template:Cite journal</ref><ref name=nat_name/> Baird's and Arnoux's beaked whales have an allopatric (non-overlapping) antitropical distribution;<ref name="ReferenceA"/> kurotsuchis are known to live in the North Pacific.<ref name=nat_name/>
Arnoux'sEdit
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Arnoux's beaked whales inhabit great tracts of the Southern Ocean. Large groups of animals, pods of up to 47 individuals, have been observed off Kemp Land, Antarctica.<ref name="ReferenceA">Template:Cite journal</ref> Beachings in New Zealand and Argentina indicate the whale may be relatively common in the Southern Ocean between those countries and Antarctica; sporadic sightings have been recorded in polar waters, such as in McMurdo Sound.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It has also been spotted close to South Georgia and South Africa, indicating a likely circumpolar distribution. The northernmost stranding was at 34 degrees south, indicating the whales inhabit cool and temperate, as well as polar, waters. There is no stock report for the Arnoux's beaked whale to date by NOAA.
Baird'sEdit
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Baird's beaked whale is found in the North Pacific Ocean, the Sea of Japan and the southern part of the Sea of Okhotsk.<ref name=":7" /> They appear to prefer seas over steep cliffs at the edge of the continental shelf, but are known to migrate to oceanic islands and to near shore waters where deep cliffs locate next to landmasses such as at Rishiri Island and in Tsugaru Strait, Shiretoko Peninsula, Tokyo Bay, and Toyama Bay.<ref name=":1" />
The continental shelf was reported in the Alaska stock report as the whales migrate to the shelf in the summer months during when the water temperature are at the highest.<ref name=":8">Template:Cite journal</ref> According to the California/Oregon/Washington NOAA stock assessment report the Baird's beaked whales can be found in the deep waters along the continental slopes of the North Pacific Ocean.<ref name="Balcomb" /><ref name=":9" /><ref name=":10">Template:Cite journal</ref> They are often seen along the slope between late spring to early fall.
Specimens have been recorded as far north as the Bering Sea and as far south as the Baja California Peninsula.<ref name=":3" /><ref name=":9">MacLeod, Colin D., et al. "Known and inferred distributions of beaked whale species (Cetacea: Ziphiidae)." Journal of Cetacean Research and Management 7.3 (2006): 271-286.</ref> They are also found on the east side and the southern islands (Izu and Bonin Islands) of Japan on the west although it is unclear whether records at these islands are of Berardius bairdii. Southern limits of historical occurrences in east Asian were unclear, while there had been either a stranding or a catch in East China Sea at Zhoushan Islands in the 1950s,<ref name="ZhoushanStranding">Template:Cite journal</ref><ref name="Kasuya2017">Kasuya T.(jp). 2017. Small Cetaceans of Japan: Exploitation and Biology Template:Webarchive. "13.3.2 Regional distribution and population structure". CRC Press. Retrieved on 25 September 2017</ref> and was a disentanglement at Kamae, Ōita.<ref>Hirano K.. 第四章 哺乳動物 Template:Webarchive (pdf). Retrieved on 27 February 2017</ref> Whales off the east coast of North America seems to approach coasts less frequently than in the western North Pacific, but they may travel further south than in Japan. Historical distributions of southward migrations or vagrants in Asian waters are unknown as the whales wintering from Bōsō Peninsula and in Tokyo Bay to Sagami Bay and around Izu Ōshima have been severely depleted or nearly wiped out by modern whaling (recently whalers shifted their major hunting grounds from Bōsō Peninsula to further north due to the very small numbers of whales still migrating to the former habitats). Within the Sea of Japan, the first scientific approaches to the species were made in Peter the Great Gulf, and the whales can widely distribute more on Japanese archipelago from west of Rebun Island to west of Oki Islands on unknown regularities, and major whaling grounds were in Toyama Bay and Oshima Peninsula.<ref name="Nishimura1970">Template:Cite journal</ref><ref name="Kasuya2017" />
Baird's beaked whales are not found in southern Chinese waters because they prefer cooler waters, but may be seasonal in colder northern waters.<ref name="AMB12">Template:Cite journal</ref> Capture records by Japanese whalers suggest that there may have been historical migrant groups of Baird's beaked whales that once regularly reached the Yellow and Bohai Seas, especially around the island of Lingshan off Jiaozhou Bay and off Dalian, <ref>Template:Cite journal</ref> This may have included regions at least as far south as the Zhoushan archipelago.<ref name="ZhoushanStranding" /> 12 individuals were caught as by-catch along the east coasts of the Korean Peninsula between 1996 and 2012.<ref name="EastSea">Template:Cite book</ref> Canada; Japan; Korea, Democratic People's Republic of Korea; Mexico; Russian; United States, (Taylor et al. 2008). Endemic to the North Pacific Ocean and the adjacent seas. There are two different stocks of Baird beaked whales that the National Oceanic and Atmospheric Administration (NOAA) keeps track of for management of the species, the Alaska stock and the California-Oregon-Washington stock. (NOAA website). According to the Alaska 2017 stock report, the range of the Baird's beaked whale is north of the Cape Navarn (62o N) and Central Sea of Okhotsk (57o N) that spans to St. Matthew Island, the Pribilof Islands, and the northern Gulf of Alaska. (Alaska Stock assessment report and Balcomb 1989).
The seasonal distribution can be observed when the Baird's beaked whales spend the summer months in the Sea of Okhotsk and the Bering Sea between April–May to October. (Tomilin 1957, Kasuya 2002, Alaska Stock assessment report 2017). The wintering habitats is assumed to be located in the northern Gulf of Alaska which was determined by using acoustic detection, (Baumann-Pickering et al. 2012b. and Alaska Stock assessment report 2017.)
Sato'sEdit
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B. minimus is currently known to reside in only the central and western North Pacific Ocean. The species' range includes portions of Japan, Russia, and Alaska, between 40°N and 60°N and 140°E and 160°W. However, this distribution is based primarily on data collected from stranded specimens, and its range may extend further.<ref name=nat_name/><ref name=":6"/><ref name=IUCNminimus/>
BehaviorEdit
Little is known about the behavior of Arnoux's beaked whale, but it is expected to be similar to that of Baird's. Distinctions between the two species are so slight that they are speculated to be the same, although genetic makeup and geographic distribution offer evidence otherwise.<ref name="Dalebout" /> Baird's beaked whales generally move in pods of 5 to 20 individuals, with groups of 50 observed in rarer circumstances.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Congregating groups of Baird's whales are led by a single large male. Scarring among males indicate competition for this leadership position that must entail more breeding opportunities and gives evidence that the species' behaviors portray sexual selection.<ref name=":2">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Potentially one of the deepest diving cetaceans, they can dive for an hour at a time, predating on deep-water and bottom-dwelling fish, cephalopods, and crustaceans. When not diving, they drift along the surface.<ref name=":4" /> The deep diving whales can dive to depths of Template:Convert, and when feeding, they generally prefer deep waters near the continental shelf or around seamounts, where high biological activity is present in shallower waters.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The deepest recorded dive is Template:Convert.<ref name=plosone-2014/><ref name=NatGeoDeepest>Template:Cite magazine</ref>
Diel variation in behavior suggests that beaked whales spend less time at the surface during the day than they do at night, so as to avoid surface predators like sharks and killer whales.<ref>Template:Cite journal</ref> Considering the extent of whaling on the Baird's species, the pod's uninfluenced structure is not well known. To date, two-thirds of the whales caught have been male, despite the fact that females are somewhat larger than males and would be thought to be the preferred targets for whalers.<ref name=":5" /> They are listed as least concern under the IUCN Red List<ref name="IUCN1"/> and not listed as depleted under the MMPA.<ref name=":10" /> They are not being hunted for research due to Japan pulling out of the whaling commission in 2018/2019.
Observations of Arnoux's beaked whales in Doubtful Sound, New Zealand in the same seasons in 2009<ref>Matthews Z., Whales at Doubtful Sound, Fiordland Kindergarten-Blog of Fiordland Nature Discovery, 28 April 2009, {{#invoke:citation/CS1|citation |CitationClass=web }}., Retrieved 4 May 2014</ref> and in 2010<ref>Department of Conservation, April 2011, Fiordland Coastal Newsletter - Conservation for prosperity – Tiakina te taiao, kia puawai, http://www.fiordlandhelicopters.co.nz/wp-content/uploads/2011/05/Fiordland-Coastal-Newsletter-April-2011.pdf Template:Webarchive., Retrieved 4 May 2014</ref> indicate that this species may possess a form of bond to locations similar to those of other species such as right whales. Another 4 or 5 sightings have been recorded in the Doubtful Sound between 2007 and in 2011.<ref>Rockwell D.H., 2009, When in Rome, Do as the Whales Do! Template:Webarchive</ref><ref>Hudgins J., Bachara W., 2014. Multiple Opportunistic Observations of Arnoux’s beaked whales in Doubtful Sound (Patea). SC/65b/SM19. Retrieved 14 May 2014</ref> Underwater recordings, made in the austral summer in the Antarctic of a large group of 47 Arnoux's beaked whales showed that they were highly vociferous animals at this time. The whales produced clicks, click trains, and frequency modulated pulses and whistles which gives their vocalizations a characteristic warbling aural impression.<ref name="ReferenceA" /> The group swam in coordinated positions along the ice edge, some of them splitting and reassembling.<ref name="ReferenceA" />
ReproductionEdit
Mating in Baird's beaked whales happens in the months of October and November and calving occurs in March and April after a 17-month gestational period.<ref name=":2" /> Scarring among males indicate competition for leadership position that must entail more breeding opportunities and gives evidence that the species' behaviors portray sexual selection.<ref name=":2" /><ref name=":5" /> The sex ratio seems to be skewed in favor of males from observational data; with some observations indicating as high is 3:1.<ref>Omura, Hideo, Kazuo Fujino, and Seiji Kimura. "Beaked whale Berardius bairdi of Japan, with notes on Ziphius cavirostris." Scientific Reports of the Whales Research Institute 10 (1955): 89-132.</ref> Males are recorded to live longer. Males live 39 years longer than females with the adult sex ratio strongly biases toward males and the female's exhibit high annual ovulation.<ref name=":5" /> It is possible that these results are seasonal abundances of different sexes in the region studied. They exhibit a slight reverse sexual dimorphism with females tending to be larger than males in size. The females have no post-reproductive stage.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=":5" /> Cetaceans in general have an interbirth interval which is the time between births of new calves. The mysticetes tend to have two or three years or relative to body size intervals whereas the odontocete interbirth intervals are more varied.<ref name=":5" /> Baird beaked whales have interbirth intervals similar to mysticeti to their size than they do with other odontocetes.<ref name=":5" /> In July 2006, in the Sea of Cortez, Mexico, there was summer stranding event of 10 males of mixed age composition that was highly suggestive of male alloparental care.<ref>Template:Cite journal</ref><ref name=":3">Urban, Jorge & Cárdenas Hinojosa, Gustavo & Gomez Gallardo Unzueta, Alejandro & González-Peral, U & Del Toro-Orozco, Wezddy & Brownell Jr, RL. (2007). Mass stranding of Baird's beaked whales at San Jose Island, Gulf of California, Mexico. Latin American Journal of Aquatic Mammals. 6. 83-88. 10.5597/lajam00111.</ref> Females are slightly larger than the males and exhibit high annual ovulation and pregnancy rates. Males live about 30 years longer than the females with this sex ratio biased toward males it is speculated that the males provide alloparetnel care to offspring which in turn allows the females to have a shorten birth interval frequency.<ref name=":5" />
FeedingEdit
Baird's beaked whale has a diet that consists primarily of deep sea fish and cephalopods found at its preferred dive depths (1000–1777m).<ref name=plosone-2014>Template:Cite journal</ref><ref name=NatGeoDeepest/> On rare occasions, it has been known to eat octopus, lobster, crab, rockfish, herring, starfish, pyrosomes and sea cucumbers.<ref name=":7">Template:Cite journal</ref> Baird's beaked whales in the southern Sea of Okhotsk diet consists of deep-water gadiform fishes and cephalopods.<ref name=":7" /> The species has a mean dive time of about 1 hour, which suggests a long search and handling time.<ref name=":8" /><ref name=":7" /> Its generalist feeding strategy may be reflective of limited prey availability at such depths or regions, as mammals become more general feeding strategists as prey diversity decreases. It may also explain the species' migrational patterns around the North Pacific.<ref name=":7" /> In summer months, Baird's beaked whale can be found off the Pacific coast of Japan where demersal fish are abundant.<ref name=":7" /> Stomach content analysis's found that Baird's beaked whale feeds in benthic zones both day and night. This behavior differs from its other Odontocete relatives (namely the common dolphin and Dall's porpoise) who feed in mesopelagic regions during the day when the light can penetrate the water column.<ref>Ohizumi, H. , Isoda, T. , Kishiro, T. and Kato, H. (2003), Feeding habits of Baird's beaked whale Berardius bairdii, in the western North Pacific and Sea of Okhotsk off Japan. Fisheries Science, 69: 11-20. doi:10.1046/j.1444-2906.2003.00582.x</ref> This suggests that Baird's beaked whale does not rely as much on its sense of sight and has evolved to navigate and hunt competently with echolocation.<ref>Shingo Minamikawa, Toshihide Iwasaki and Toshiya Kishiro, Diving behaviour of a Baird's beaked whale, Berardius bairdii, in the slope water region of the western North Pacific: first dive records using a data logger, Fisheries Oceanography, 16, 6, (573–577), (2007)</ref> There is little information on the foraging behavior of Baird's beaked whales and their ecological role in the marine ecosystem.<ref name=":7" />
ConservationEdit
Arnoux's beaked whale has rarely been exploited, and although no abundance estimates are available, the population is not believed to be endangered. Arnoux's beaked whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU).<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Baird's beaked whale is listed by the Mammalogical Society of Japan as rare in Japanese coastal waters. The Baird's beaked whale is listed on Appendix II<ref name="Appendices">"Appendix II Template:Webarchive" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009.</ref> of the convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II<ref name="Appendices"/> as it has an unfavorable conservation status or would benefit significantly from international co-operation organised by tailored agreements. It is considered Least Concern by the IUCN.<ref name="IUCN1"/> They are not listed as "threatened" or "endangered" under the endangered species act nor depleted under the MMPA.<ref name=":10" /> There is preliminary evidence of the Baird's beaked whale being sensitive to anthropogenic aquatic noise pollution, as other odontocete species are.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Anthropogenic sound sources such as military sonar and seismic testing. The testing of military sonar has been recorded to effect the diving behavior of beaked whales. This implication on the whales effects their ability to decompress upon surfacing and results in the whales suffering the bends, increase nitrogen gas bubbles in the blood.<ref name=":4" /><ref name=":10" />
In the 20th century, Baird's beaked whales were hunted primarily by Japan and to a lesser extent by the USSR, Canada and the United States. The USSR reported killing 176 before hunting ended in 1974. Canadian and American whalers killed 60 before halting in 1966. Japan killed around 4000 individuals before the 1986 moratorium on whaling (about 300 were killed in the most prolific year, 1952). Baird's beaked whales are not protected under the International Whaling Commission's moratorium on commercial whaling, as Japan argues they are a 'small cetacean' species, despite being larger than minke whales, which are protected. Each year, 62 Baird's beaked whales are hunted commercially in Japan, with the meat sold for human consumption. A landing and processing of a Baird's beaked whale was filmed<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> by the Environmental Investigation Agency on 7 August 2009. Meat and blubber food products of the whales have been found to contain high levels of mercury and other pollutants, such as polychlorinated biphenyls (PCBs).
Population statusEdit
Estimates of the abundance of populations are unavailable.<ref name=":10" /> They are not listed as "threatened" or "endangered" under the endangered species act nor depleted under the MMPA.<ref name=":10" />
ThreatsEdit
The Baird's beaked whale is hunted by Japan. As of 2019, Japan pulled out of the International Whaling Commission (IWC) to continue harvesting whales commercially.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The California large mesh drift gillnet fishery has known to interact with the CA-OR-WA population. There are habitat concerns for the Alaska stock, in areas with oil and gas activities or shipping and military activities are high.<ref name=":10" /> For the Baird's beaked whale.Template:Clarify<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Anthropogenic sound sources such as military sonar and seismic testing. The testing of military sonar has been recorded to effect the diving behavior of beaked whales. This implication on the whales effects their ability to decompress upon surfacing and results in the whales suffering the bends, increase nitrogen gas bubbles in the blood.<ref name=":4" /><ref name=":10" />
Common namesEdit
- B. arnuxii is known as Arnoux's beaked whale, southern four-toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale, and southern porpoise whale. In Japanese it is known as minami-tsuchi (ミナミツチ), literally "Southern hammer (i.e. Berardius)".
- B. bairdii is known as Baird's beaked whale, northern giant bottlenose whale, North Pacific bottlenose whale, giant four-toothed whale, northern four-toothed whale, and North Pacific four-toothed whale. In Japanese, it is called tsuchi-kujira (ツチクジラ), where tsuchi means "hammer", in reference to the way the head vaguely resembles a traditional Japanese hammer or mallet, and kujira means "whale".<ref name="auto">1995, {{#invoke:Lang|lang}} (Daijisen) (in Japanese), Tōkyō: Shogakukan, Template:ISBN</ref>
- The newly described species, B. minimus, is traditionally known to Japanese whalers as kuro-tsuchi (黒ツチ),<ref name=nat_name/> where kuro means "black" and tsuchi means "hammer".<ref name="auto"/> The Society for Marine Mammalogy lists Sato's beaked whale as an additional common name for B. minimus.<ref name="sato">{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
SpecimensEdit
- MNZ MM002654 B. arnuxii Arnoux's beaked whale, collected Riverton, near Invercargill, New Zealand, 27 January 2006
See alsoEdit
ReferencesEdit
- "Giant Beaked Whales" in the Encyclopedia of Marine Mammals pages 519-522 Teikyo Kasuya, 1998. Template:ISBN
- National Audubon Society Guide to Marine Mammals of the World Reeves et al., 2002. Template:ISBN.
- Whales, Dolphins and Porpoises Carwardine, 1995. Template:ISBN
- An image of a Baird's Beaked Whale at monteraybaywhalewatch.com
External linksEdit
- The Environmental Investigation Agency
- Whale & Dolphin Conservation Society (WDCS)
- Baird's Beaked Whale - ARKive bio
- Arnoux's Beaked Whale - ARKive bio
- Template:Usurped
- Template:Usurped
- Rare whale gathering sighted - BBC News
- Species Convention on Migratory species page on Baird's Beaked Whale
- Voices in the Sea - Sounds of the Baird's (Giant) beaked Whale Template:Webarchive