Whale populations were drastically reduced in the 20th century from intensive whaling, which lead to a moratorium on hunting by the International Whaling Commission in 1982.[7] Smaller cetaceans are at risk of accidentally getting caught by fishing vessels using, namely, seine fishing, drift netting, or gill netting operations.[8]
The following is a list of currently existing (or, in the jargon of taxonomy) 'extant' species of the infraordercetacea (for extinct cetacean species, see the list of extinct cetaceans). The list is organized taxonomically into parvorders, superfamilies when applicable, families, subfamilies when applicable, genus, and then species. In tabular form, seven descriptors are given for each species: the common name; the scientific name; the IUCN Red List status; a global population estimate; a global map with its range; its weight with an image of its shape, and its size relative to a human; and a photograph.
Where available, the global population estimate has been listed. When not cited or footnoted differently, these are from the IUCN Red List of Threatened Species (v. 2014.3; data current at 20 January 2015).[9]
The baleen whales, also called whalebone whales or great whales, form the parvorder Mysticeti. Baleen whales are characterized by having baleen plates for filter feeding and two blowholes.[10]
The family Balaenidae, the right whales, contains two genera and four species. All right whales have no ventral grooves; a distinctive head shape with a strongly arched, narrow rostrum, bowed lower jaw; lower lips that enfold the sides and front of the rostrum; and long, narrow, elastic baleen plates (up to nine times longer than wide) with fine baleen fringes.[11]
Rorquals are the largest group of baleen whales, with eleven species in three genera. They include the largest animal that has ever lived, the blue whale. They take their name from a Norwegian word meaning "furrow whale"; all members of the family have a series of longitudinal folds of skin running from below the mouth back to the navel (except the sei whale, which has shorter grooves). They allow the mouth to expand immensely when feeding.[14] All rorquals have these unique folds.[11]
Subfamily Balaenopteridae – one genus, nine species
The pygmy right whale shares several characteristics with the right whales, with the exception of having a dorsal fin. Also, pygmy right whales' heads are no more than one quarter the size of their bodies, whereas the right whales' heads are about one-third the size of their bodies.[11] The pygmy right whale is the only extant member of its family.
The toothed whales (parvorder Odontoceti), as the name suggests, are characterized by having teeth (rather than baleen). Toothed whales are active hunters, feeding on fish, squid, and in some cases other marine mammals.[20]
Oceanic dolphins are the members of the family Delphinidae. As the name implies, they tend to be found in the open seas, unlike the river dolphins, although a few species such as the Irrawaddy dolphin are coastal or riverine.
The Delphinidae are characterized by having distinct beaks (unlike the Phocoenidae), two or more fused cervical vertebrae and 20 or more pairs of teeth in their upper jaws. None is more than 4m long.[11]
The dwarf and pygmy sperm whales resemble sperm whales, but are far smaller. They have blunt, squarish heads with narrow, underslung jaws; the flippers are set far forward, close to the head and their dorsal fins are set far back down the body.[23]
The family Lipotidae contains only the baiji. DNA evidence suggests it separated from oceanic dolphins about 25 million years ago.[24] The species was declared functionally extinct in 2006 after an expedition to estimate the population found none.
The Monodontidae lack dorsal fins, which have been replaced by tough, fibrous ridges just behind the midpoints of their bodies and are probably an adaptation to swimming under ice, as both do in their Arctic habitat. The flippers are small, rounded and tend to curl up at the ends in adulthood. All, or almost all, the cervical vertebrae are unfused, allowing their heads to be turned independently of their bodies.[11]
Porpoises are small cetaceans of the family Phocoenidae. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen. The most obvious visible differences between the two groups are that porpoises have a less pronounced beak, and have spade-shaped teeth as opposed to conical.[25]
Porpoises, divided into seven species, live in all oceans. They span from species that live almost exclusively coastal and in rivers (finless porpoises) to species that are entirely oceanic (spectacled porpoise).
The sperm whale characteristically has a large, squarish head one-third the length of its body; the blowhole is slightly to the left hand side; the skin is usually wrinkled; and it has no teeth on the upper jaw.
The Platanistidae were originally thought to hold only one species (the South Asian river dolphin), but, based on differences in skull structure, vertebrae and lipid composition, it was split into two separate species in the early 1970s, before being demoted back to subspecies in 1988.[30] However, more recent studies support them being distinct species.[31]
The La Plata dolphin is the only species of the family Pontoporiidae and genus Pontoporia. These dolphins are known for their long beak in relation to their relatively small body size. They have a small geographic range and are mainly found in the waters along the east coast of South America. La Plata dolphins are exclusively marine organisms, however, they are grouped with river dolphins due to the fact that they reside in the La Plata River which is a salt-water estuary. With their white or sometimes pale brown coloration, fishermen tend to call them "the white ghost", as they also tend to stray away from any human interaction.[34]
A beaked whale is any of at least 22 species of whale in the family Ziphiidae. Several species have only been described in the last two decades. Six genera have been identified.
They possess a unique feeding mechanism among cetaceans known as suction feeding. They are characterized by having a lower jaw that extends at least to the tip of the upper jaw, a shallow or non-existent notch between the tail flukes, a dorsal fin set far backwards, three of four fused neck vertebrae, extensive skull asymmetry and two conspicuous throat grooves forming a 'V' pattern (which aid in sucking).[11]
↑ The Society for Marine Mammalogy considers Eden's whale a smaller morph of the more widespread Bryde's whale based on current research.[15]
↑ Population estimated to be in the low thousands at the highest.
↑ There are estimated to be at least several million common dolphins worldwide, but several large portions of its range have not been surveyed.
↑ The only population estimate is of 38,900 individuals in the eastern tropical Pacific Ocean.
↑ Total population is not known. There are estimated to be in excess of 200,000 in the Southern Ocean. The North Atlantic population is not known.
↑ Total population not known. There are 150,000 individuals in the eastern tropical Pacific Ocean. There are estimated to be more than 30,000 animals in the western Pacific, off the coast of Japan.
↑ The population around the continental shelf of the United States has been recorded to be in excess of 60,000. In the Pacific, a census recorded 175,000 individuals in eastern tropical waters and 85,000 in the west. No global estimate of population exists
↑ There are estimated to be at least 320,000 Fraser's dolphins worldwide, but several large portions of its range have not been surveyed
↑ The genus Lagenorhynchus is under revision and likely to be split into several different genera
↑ Estimates of various stocks throughout the North Atlantic give an overall value into the high tens or low hundreds of thousands
↑ Total population unknown but thought to be locally common – it is the most common dolphin found around the Falkland Islands
↑ Varying population estimates for areas around California and the North Pacific give a total of up to 400,000
↑ Surveys suggest this is the most common dolphin off of Chilean waters
↑ Local estimates include 70–80,000 in the Antarctic, 8,000 in the tropical Pacific (although tropical waters are not the orca's preferred environment, the sheer size of this area — 19 million square kilometres — means there are thousands of orcas), up to 2,000 off Japan, 1,500 off the cooler northeast Pacific and 1,500 off Norway
↑ Estimates for eastern tropical Pacific are 45,000 and another recent survey estimates population to be 1,200 for the eastern Sulu Sea, no global estimate is known
↑ The total population is unknown. The eastern Pacific was estimated to have in excess of 40,000 individuals and is probably the home of the largest grouping
↑ Population estimated to be in the low tens of thousands
↑ As of November 2021, the Araguaian river dolphin is not recognized by the Society for Marine Mammalogy, which cites small sample size[15]
↑ No global population estimates have been made. One survey estimated a population of about 11,000 in the eastern Pacific
↑ No global population estimates have been made. One survey estimated a population of about 11,000 in the eastern Pacific
↑ A survey from November–December 2006 failed to find any individuals. Another survey, from 1997, counted only 13 individuals. In 1986, surveys estimated the number to be at about 300
↑ There are estimated to be 40,000 individuals in the Beaufort Sea, 25,000 in Hudson Bay, 18,000 in the Bering Sea and 28,000 in the Canadian High Arctic. The population in the St. Lawrence estuary is estimated to be around 1000
↑ There is not enough data to place finless porpoises on the endangered species list
↑ There are no good estimates of the animals' abundance. However a comparison of two surveys, one from the late 1970s and the other from 1999/2000 shows a decline in population and distribution.
↑ In China, they are endangered. Their propensity for staying close to shore places them in great danger from fishing.
↑ Nothing is known of the abundance of this porpoise. It was the most commonly encountered species during preliminary beach surveys undertaken on Tierra del Fuego.
↑ The most recent estimate for the North Pacific and Bering Sea is 1,186,000.
↑ The total number of sperm whales throughout the world is unknown. Crude estimates, obtained by surveying small areas and extrapolating the result to all the world's oceans, range from 200,000 to 2,000,000 individuals
↑ Arnoux's beaked whales seem to be relatively abundant in Cook Strait during summer
↑ Virtually nothing is known about the abundance of Baird's beaked whales, except they are not rare as was formerly thought
↑ Nothing is known about the relative abundance of this species or its population composition
↑ Because of the difficulty of identifying the species the total global population is unknown
↑ Total population is unknown but likely to be of the order of 10,000
↑ A 2002 survey estimates there are 766 animals around Hawaii. No other population estimates exist for other locales
Related Research Articles
Cetacea is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver.
Porpoises are small dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.
The white-beaked dolphin is a marine mammal belonging to the family Delphinidae in the suborder Odontoceti.
Dall's porpoise is a species of porpoise endemic to the North Pacific. It is the largest of porpoises and the only member of the genus Phocoenoides. The species is named after American naturalist W. H. Dall.
The four-toothed whales or giant beaked whales are beaked whales in the genus Berardius. They include Arnoux's beaked whale in cold Southern Hemispheric waters, and Baird's beaked whale in the cold temperate waters of the North Pacific. A third species, Sato's beaked whale, was distinguished from B. bairdii in the 2010s.
Arnoux's beaked whale, also called the southern four-toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale and southern porpoise whale is one of the species of Berardius. Arnoux's and Baird's beaked whales are so similar that researchers debated whether or not they are simply two populations of the same species, until genetic evidence and their wide geographical separation led them to be classified as separate. Little is known about their behavior due to infrequent encounters with live individuals.
Fraser's dolphin or the Sarawak dolphin is a cetacean in the family Delphinidae found in deep waters in the Pacific Ocean and to a lesser extent in the Indian and Atlantic Oceans.
The northern right whale dolphin is a small, slender species of cetacean found in the cold and temperate waters of the North Pacific Ocean. Lacking a dorsal fin, and appearing superficially porpoise-like, it is one of the two species of right whale dolphin.
The hourglass dolphin is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage but has a circumpolar distribution.
The pantropical spotted dolphin is a species of dolphin found in all the world's temperate and tropical oceans. The species was beginning to come under threat due to the killing of millions of individuals in tuna purse seines. In the 1980s, the rise of "dolphin-friendly" tuna capture methods saved millions of the species in the eastern Pacific Ocean and it is now one of the most abundant dolphin species in the world.
The dwarf sperm whale is a sperm whale that inhabits temperate and tropical oceans worldwide, in particular continental shelves and slopes. It was first described by biologist Richard Owen in 1866, based on illustrations by naturalist Sir Walter Elliot. The species was considered to be synonymous with the pygmy sperm whale from 1878 until 1998. The dwarf sperm whale is a small whale, 2 to 2.7 m and 136 to 272 kg, that has a grey coloration, square head, small jaw, and robust body. Its appearance is very similar to the pygmy sperm whale, distinguished mainly by the position of the dorsal fin on the body–nearer the middle in the dwarf sperm whale and nearer the tail in the other.
Cetacean bycatch is the accidental capture of non-target cetaceans such as dolphins, porpoises, and whales by commercial fisheries. Bycatch can be caused by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets.
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 southern bottlenose whale is a species of whale, in the ziphiid family, one of two members of the genus Hyperoodon. Seldom observed, the southern bottlenose whale is resident in Antarctic waters. The species was first described by English zoologist William Henry Flower in 1882, based on a water-worn skull from Lewis Island, in the Dampier Archipelago, Western Australia. They live in deep ocean waters over 1000 meters.
William F. Perrin was an American biologist specializing in the fields of cetacean taxonomy, reproductive biology, and conservation biology. He is best known for his work documenting the unsustainable mortality of hundreds of thousands of dolphins per year in the tuna purse-seine fishery of the eastern tropical Pacific. This work became a primary motivation for the U.S. Marine Mammal Protection Act (1972). His work on cetacean taxonomy was acknowledged in 2002 when a newly recognized species of beaked whale, Perrin's beaked whale, which was named in his honor.
Cetaceans form an infra-order of marine mammals. In 2020, approximately 86 species of cetaceans had been identified worldwide. Among these species, at least 35 have been sighted in the wider Caribbean region with very widespread distribution and density variations between areas. Caribbean waters are a preferred breeding site for several species of mysticeti, who live further north the rest of the year. The tucuxi and the boto live at the southern periphery of the Caribbean region in the freshwaters of the Amazon River and surrounding drainage basins.
↑ Agnarsson, I.; May-Collado, LJ. (2008). "The phylogeny of Cetartiodactyla: the importance of dense taxon sampling, missing data, and the remarkable promise of cytochrome b to provide reliable species-level phylogenies". Mol Phylogenet Evol. 48 (3): 964–985. doi:10.1016/j.ympev.2008.05.046. PMID18590827.
↑ Price, SA.; Bininda-Emonds, OR.; Gittleman, JL. (2005). "A complete phylogeny of the whales, dolphins and even-toed hoofed mammals – Cetartiodactyla". Biol Rev Camb Philos Soc. 80 (3): 445–473. doi:10.1017/s1464793105006743. PMID16094808. S2CID45056197.
↑ Karlsen, K. (1962). "Development of tooth germs and adjacent structures in the whalebone whale (Balaenoptera physalus)". Hvalrådets Skrifter: Scientific Results of Marine Biological Research. 45: 1–56.
↑ Miyashita, T; Kato, H (1998). "Recent data on the status of right whales in the NW Pacific Ocean". International Whaling Commission. Cambridge, UK.{{cite web}}: Missing or empty |url= (help)
↑ Huggenberger, S.; Leidenberger, S.; Oelschläger, H. H. A. (December 13, 2016). "Asymmetry of the nasofacial skull in toothed whales (Odontoceit)". Journal of Zoology. 302 (1): 15–23. doi:10.1111/jzo.12425.
↑ Bjorge, Arne; A Tolley, Krystal (2008). "Harbor porpoise Phocoena phocoena". In William F. Perrin; Bernd Wursig; J. G.M. Thewissen (eds.). Encyclopedia of Marine Mammals. pp.530–532.
Rice, Dale W. (1998). Marine mammals of the world: systematics and distribution. Society of Marine Mammalogy, Special Publication No. 4. ISBN1891276034.
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