Gervais's beaked whale | |
---|---|
Size compared to an average human | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Artiodactyla |
Infraorder: | Cetacea |
Family: | Ziphiidae |
Genus: | Mesoplodon |
Species: | M. europaeus |
Binomial name | |
Mesoplodon europaeus (Gervais, 1855) | |
Gervais's beaked whale range |
Gervais's beaked whale (Mesoplodon europaeus), sometimes known as the Antillean beaked whale, Gulf Stream beaked whale, or European beaked whale (from which its scientific name is derived) is the most frequently stranding type of mesoplodont whale off the coast of North America. It has also stranded off South America and Africa.
Sometime between 1836 and 1841, a captain of one of the ships of the French merchant and armorer Abel Vautier came across a large animal floating at the entrance to the English Channel, its body covered by swarming gulls. He cut the head off and transported it to Caen, where he presented it to Vautier. Vautier in turn offered it to the anatomist Deslongchamps. The specimen somehow made its way to the French scientist Paul Gervais, who described it as a new species in 1855.
For several decades this remained as the only known specimen of this species, with many disregarding its specific status and claiming it merely represented an aberrant adult Sowerby's beaked whale. [3]
The species’ identity was confirmed by the discovery of two specimens from New Jersey, an immature male captured near Atlantic City in 1889 and an adult female found stranded at North Long Branch in 1905. [4]
This species is the largest of the mesoplodonts and rather gracile, elongated, and laterally compressed compared with the others. The mouthline is remarkably straight, even in males, and the two teeth of the male erupt towards the tip of the beak, and are hardly noticeable. [5] The head is overall small and tapering in outline. The melon only bulges very slightly. The coloration is dark gray on top and lighter gray on bottom. Females sometimes have lighter spots near the genitals and face, with a dark circle remaining around the eyes. Juveniles start off with a lighter coloration, but soon darken. [5] Males are 4.5 meters (15 feet) in length and females are at least 5.2 meters (17 feet) and probably weigh more than 1,200 kg (2,600 lb). Calves are believed to be 2.1 meters (6.9 feet) in length. One beached specimen may have been 48 years old. [5]
Judging by strandings, the whales occur in small groups. They probably feed on squid.
A sighting made in 1998, west of the island of Tenerife, involved three whales swimming over waters 1500 meters deep. Another small group was seen south of the island of Gran Canaria.
Although timid, the whales allowed close photos. They surfaced for a short time, and their dives lasted for around an hour. [6]
In September 2008, northeast of the island of Lanzarote, some Gervais' beaked whales were photographed breaching out of the water. [7]
On May 5, 2011, one juvenile female specimen was found dead and beached at Playa Larga in Maunabo in southeastern Puerto Rico. The juvenile had her stomach filled with (10 pounds) of plastic bags. [8]
On July 10 of the same year, one specimen was found dead in the Yucatán Peninsula, México. Further investigation is being performed to confirm the species in this case. [9]
The species is believed to be naturally rare, and no population estimates have been attempted. [5]
Since the discovery of the type specimen, it has been found off the eastern coast of the United States, Ireland, the Canary Islands, western Africa, and Ascension Island.
In August 2001, a specimen was found off São Paulo, Brazil, the southernmost specimen found to date. [10]
Although this species frequently strands, until 1998 no one had made a confirmed sighting of the species. [11] Sightings remain rare. [12]
There had been a possible stranding of this species in Israel.[ citation needed ]
The species has not been hunted and only very infrequently gets tangled in fishing nets. Gervais's beaked whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS) [13] and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS). [14] The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia. [15]
Risso's dolphin is a marine mammal and dolphin, the only species of the genus Grampus. Some of the most closely related species to these dolphins include: pilot whales, pygmy killer whales, melon-headed whales, and false killer whales. These dolphins grow to be about 10 ft in length and can be identified by heavy scarring that appears white. They are located worldwide in cold to temperate waters, but most typically found along continental shelves due to their eating habits. Risso's dolphins have a diet that contains primarily cephalopods. They are able to search for prey at various depths due to their ability to reach depths of almost 600m. Individuals typically travel in pods ranging anywhere from 10 to 50 dolphins, with which they form tight social bonds.
Andrews' beaked whale, sometimes known as the deep-crest beaked whale or splay-toothed whale, is one of the least known members of a poorly known genus. The species has never been observed in the wild, and is known only from specimens washed up on beaches.
Sowerby's beaked whale, also known as the North Atlantic or North Sea beaked whale, is a species of toothed whale. It was the first mesoplodont whale to be described. James Sowerby, an English naturalist and artist, first described the species in 1804 from a skull obtained from a male that had stranded in the Moray Firth, Scotland, in 1800. He named it bidens, which derives from the two teeth present in the jaw, now known to be a very common feature among the genus.
Hubbs' beaked whale was initially thought to be an Andrews' beaked whale when discovered by ichthyologist Carl Hubbs; however, it was named in his honor when it was discovered to be a new species. This species has the typical dentition found in the genus, but its main outstanding features are a white "cap" on the head and very extensive scarring. The species is known from 31 strandings, a few at-sea sightings, and observations of two stranded whales that were kept in captivity for 16–25 days.
Blainville's beaked whale, or the dense-beaked whale, is believed to be the widest ranging mesoplodont whale. The French zoologist Henri de Blainville first described the species in 1817 from a small piece of jaw — the heaviest bone he had ever come across — which resulted in the name densirostris. Off the northeastern Bahamas, the animals are particularly well documented, and a photo identification project started sometime after 2002.
The ginkgo-toothed beaked whale is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical-looking species, but is notable for the males not having any scarring.
Gray's beaked whale, sometimes known as Haast's beaked whale, the scamperdown whale, or the southern beaked whale, is one of the better-known members of the genus Mesoplodon. This species is fairly gregarious and strands relatively frequently for a beaked whale. In the Māori language, this species is called hakurā or iheihe.
The strap-toothed beaked whale, also known as Layard's beaked whale, is one of the largest members of the Mesoplodon genus, growing to 6.2 m (20 ft) in length and reaching up to 1,300 kg (2,900 lb). The common and scientific name was given in honor of Edgar Leopold Layard, the curator of the South African Museum, who prepared drawings of a skull and sent them to the British taxonomist John Edward Gray, who described the species in 1865.
True's beaked whale is a medium-sized whale in the genus Mesoplodon. It is native to the northern Atlantic Ocean. The common name is in reference to Frederick W. True, a curator at the United States National Museum.
The tropical bottlenose whale, also known as the Indo-Pacific beaked whale or Longman's beaked whale, was considered to be the world's rarest cetacean until recently, but the spade-toothed whale now holds that position. As of 2010, the species is now known from nearly a dozen strandings and over 65 sightings. This is the only species in the genus Indopacetus.
The pygmy beaked whale, also known as the bandolero beaked whale, Peruvian beaked whale and lesser beaked whale, is the smallest of the mesoplodonts and one of the newest discoveries. There were at least two dozen sightings of an unknown beaked whale named Mesoplodon sp. A before the initial classification, and those are now believed to be synonymous with the species. The species was formally described in 1991, based on ten specimens obtained from Peru between 1976 and 1989, including a 3.72 m (12.2 ft) adult male as the type specimen. A specimen that stranded at Paracas, Peru in 1955 has since been identified as a pygmy beaked whale. Since 1987, there have been an additional 40 sightings of the species, for a total of 65.
Stejneger's beaked whale, also known as the Bering Sea beaked whale or the saber-toothed whale, is a relatively unknown member of the genus Mesoplodon inhabiting the North Pacific Ocean. Leonhard Hess Stejneger collected the type specimen on Bering Island in 1883, from which Frederick W. True provided the species' description in 1885. In 1904, the first complete skull was collected, which confirmed the species' validity. The most noteworthy characteristic of the males is the very large, saber-like teeth, hence the name.
Cuvier's beaked whale, goose-beaked whale, or ziphius is the most widely distributed of all beaked whales in the family Ziphiidae. It is smaller than most baleen whales—and indeed the larger toothed cetaceans —yet it is large among the beaked whales and smaller cetaceans, appearing somewhat like a bigger and stockier bottlenose dolphin. Cuvier's beaked whale is pelagic, generally inhabiting waters deeper than 300 m (1,000 ft), though it has been observed closer to shore on occasion. In these offshore waters, Cuvier's beaked whale executes some of the deepest, longest recorded dives among whales, and extant mammals, at 2,992 m (9,816 ft), for 222 minutes. While likely diving to forage and hunt prey, such as cephalopods, and potentially evade predators, the frequency and exact reason for these extraordinary dives is unclear. Despite its deepwater habitat, it is one of the most frequently-spotted beaked whales when surfacing.
The northern bottlenose whale is a species of beaked whale in the ziphiid family, being one of two members of the genus Hyperoodon. The northern bottlenose whale was hunted heavily by Norway and Britain in the 19th and early 20th centuries. It is one of the deepest-diving mammals known, reaching depths of 2,339 m (7,674 ft) and capable of diving for up to 130 minutes.
Perrin's beaked whale is part of the toothed whale suborder and is one of over 90 known cetaceans in existence today. Beaked whales are part of the family Ziphiidae, which are the second most diverse group out of all marine mammals with over 20 species currently recognized. Although diverse, little is understood about these timid, deep divers that can dive for up to two hours. The whales are partially named after their beak shaped jaw, which extends from their small head. The genus name Mesoplodon comes from the Greek meanings of meso- (middle), - hopla (arms), - odon (teeth), and may be translated as 'armed with a tooth in the center of the jaw'.
The Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic Area, or ACCOBAMS, is a regional international treaty that binds its States Parties on the conservation of Cetacea in their territories. The Agreement aims is to reduce threats to Cetaceans in the Mediterranean and Black Seas, as well as in the contiguous Atlantic area west of the Straits of Gibraltar.
Deraniyagala's beaked whale is a species of mesoplodont whale closely related to the ginkgo-toothed beaked whale.
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Natacha Aguilar de Soto is a Spanish marine biologist at the University of La Laguna (ULL), Tenerife, Canary Islands. She is a Ramón y Cajal research and teaching fellow at ULL and has been a Marie Skłodowska-Curie Research Fellow at ULL and at the Center for Research in Ecological Modeling (CREEM) of the University of St. Andrews (SMRU). She is the director of cetacean research within ULL's BIOECOMAC.
An unusual mortality event (UME) is a term in United States environmental law that refers to a set of strandings, morbidities, or mortalities of marine mammals that are significant, unexpected, and demanding of an immediate response. While the term is only officially defined in a statute in the US, it has been employed unofficially by cetacean conservation agencies and organizations internationally as well.