A flipper is a broad, flattened limb adapted for aquatic locomotion . It refers to the fully webbed , swimming appendages of aquatic vertebrates that are not fish .
67-530: Phoca groenlandica The harp seal ( Pagophilus groenlandicus ), also known as Saddleback Seal or Greenland Seal , is a species of earless seal , or true seal, native to the northernmost Atlantic Ocean and Arctic Ocean . Originally in the genus Phoca with a number of other species, it was reclassified into the monotypic genus Pagophilus in 1844. In Greek, its scientific name translates to "ice-lover from Greenland," and its taxonomic synonym , Phoca groenlandica translates to "Greenlandic seal." This
134-409: A fetal development phase of 8 months. There have been reported cases of twin births, but singletons are vastly more common. The fertilized egg grows into an embryo which remains suspended in the womb for up to three months before implantation, to delay birth until sufficient pack ice is available. Harp seal births are rapid, with recorded lengths as short as 15 seconds in duration. In order to cope with
201-458: A large spherical lens that improves focusing ability. Its mobile pupil helps it adapt to the intense glare of the Arctic ice. Its retina is rod-dominated and backed by a cat -like and reflective tapetum lucidum , enhancing its low light sensitivity. Its cones are most sensitive to blue-green spectra, while its rods help sense light intensity and may provide some color discrimination. Its cornea
268-642: A lesser extent, commerce. In 2019, the Department of Fisheries and Oceans estimated sustainable harvest levels for the next five years. The identified annual Canadian Total Allowable Catch (TAC) levels were 425,000 assuming harvest age structures of 95% young of the year (YOY). In 2016, 66,800 harp seals and 1,612 grey seals were harvested in Atlantic Canada. In 2005, the Independent Veterinarians' Working Group (IVWG) recommended
335-628: A long time underwater between breaths. Air is forced from the lungs during a dive and into the upper respiratory passages, where gases cannot easily be absorbed into the bloodstream. This helps protect the seal from the bends . The middle ear is also lined with blood sinuses that inflate during diving, helping to maintain a constant pressure. Phocids are more specialized for aquatic life than otariids. They lack external ears and have sleek, streamlined bodies. Retractable nipples , internal testicles , and an internal penile sheath provide further streamlining. A smooth layer of blubber lies underneath
402-408: A majority of thrust was produced during the drive phase of the fore flipper stroke cycle. Although previous findings on eared seals suggested that thrust was generated by the initial outward movement of the fore flippers or the terminal drag-based paddling phase, the 2007 study found that little or no thrust was generated during those phases. Swimming performance in sea lions is modulated by changes in
469-472: A metacarpal. In the latter (mysticetes), the first digit ray may have been lost as late as 14 million years ago. Sea turtles evolved in the Cretaceous . Their flippers developed gradually by a series of stepwise adaptations, with the most fundamental traits of flippers appearing in the deepest nodes (the earliest times) in their phylogeny . These initial traits evolved only once among chelonioids , and
536-515: A monophyletic origin for all pinnipeds from a single ancestor, possibly Enaliarctos , most closely related to the mustelids and bears . Monk seals and elephant seals were previously believed to have first entered the Pacific through the open straits between North and South America, with the Antarctic true seals either using the same route or travelled down the west coast of Africa. It
603-561: A more defined dorsal harp marking and a darker head, while some females never develop the marking and remain spotted. Compared to other phocid seals, the harp seal dives from shallow to moderately deep depths. Dive depth varies with season, time of day and location. In the Greenland Sea sub-population, the average dive rate is around 8.3 dives per hour and dives range from a depth of less than 20 to over 500 m. Dive duration ranges from less than two minutes to just over 20 minutes. During
670-439: A short period. This allows the mother to return to the sea in time to replenish her reserves. Lactation ranges from five to seven weeks in the monk seal to just three to five days in the hooded seal . The mother ends nursing by leaving her pup at the breeding site to search for food (pups continue to nurse if given the opportunity). "Milk stealers" that suckle from unrelated, sleeping females are not uncommon; this often results in
737-430: A soft tissue flipper that encases most of the forelimb, and elongated digits with an increased number of phalanges. Hyperphalangy is an increase in the number of phalanges beyond the plesiomorphic mammal condition of three phalanges-per-digit. This trait is characteristic of secondarily aquatic vertebrates with flippers. Hyperphalangy was present among extinct ichthyosaurs, plesiosaurs, and mosasaurs. Cetaceans are
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#1732787482477804-561: A three-step process for hunters to kill the seals with little or no pain for the seals, as long as the process is completed in rapid succession. The process is as follows: In 2009, this process was included in both the 'Conditions of License' for the Canadian hunt as well as the Canadian Marine Mammal Regulations. The Canadian seal hunt is monitored by the Canadian government. Although approximately 70% of
871-694: A total of 31 vagrants were recorded between 1800 and 1988. More recently, they reached Lindisfarne in Northumberland in September 1995, and the Shetland Islands in 1987. The latter was linked to a mass movement of harp seals into Norwegian waters; by mid-February 1987, 24,000 were reported drowned in fishing nets and perhaps 30,000 (about 10% of the world population) had invaded fjords as far south as Oslo . The animals were emaciated, likely due to commercial fishing causing competition for
938-665: A touch sense with labeled line coding, and underwater, also respond to low-frequency vibrations, such as movement. Like most pinnipeds , harp seals are carnivorous . They have a diverse diet including several dozen fish and invertebrate species. The White Sea population migrates northward in the summer to forage extensively in the Barents Sea . Where common prey items include krill , capelin ( Mallotus villosus), herring ( Clupea harengus), flat fish and Gadiform fish. Harp seals prefer some prey, though their diet depends largely on prey abundance. Diet and abundance analysis of
1005-460: Is Noriphoca gaudini from the late Oligocene or earliest Miocene ( Aquitanian ) of Italy . Other early fossil phocids date from the mid-Miocene, 15 million years ago in the north Atlantic. Until recently, many researchers believed that phocids evolved separately from otariids and odobenids ; and that they evolved from otter -like animals, such as Potamotherium , which inhabited European freshwater lakes. Recent evidence strongly suggests
1072-521: Is a fast ice breeder and is believed to have a promiscuous mating system . Breeding occurs between mid-February and April. Courtship peaks during mid-March and involves males performing underwater displays, using bubbles, vocalizations, and paw movements to court females. Females, who remain on the ice, will resist copulation unless underwater. Females mature sexually between ages five to six. Annually thereafter, they may bear one pup, usually in late February. The gestation period lasts about 11.5 months, with
1139-403: Is abrupt; the mother turns from nursing to promiscuous mating, leaving the pup behind on the ice. While courtship starts on the ice, mating usually takes place in the water. After abandonment, in the post-weaning phase, the pup becomes sedentary to conserve body fat. Within a few days, it sheds its white coat, reaching the "beater" stage. This name comes from the sound a beater's tail makes as
1206-469: Is aided by a specialized skull, mandible, and tooth morphology. However, despite morphological specialization, most phocids are opportunistic and employ multiple strategies to capture and eat prey. For example, the leopard seal, Hydrurga leptonyx , uses grip and tear feeding to prey on penguins, suction feeding to consume small fish, and filter feeding to catch krill. [REDACTED] Flipper (anatomy) In animals with two flippers, such as whales ,
1273-437: Is believed to be under −10 degrees Celsius in air. Blubber insulates the harp seal's core but does not insulate the flippers to the same extent. Instead, the flippers have circulatory adaptations to help prevent heat loss. A thick coat of blubber insulates its body and provides energy when food is scarce or during fasting . Blubber also streamlines its body for more efficient swimming. Brown fat warms blood as it returns from
1340-409: Is called the "dorsal fin" and the large cetacean tails are referred to primarily as flukes but occasionally as "caudal fins"; neither of these structures are flippers. Some flippers are very efficient hydrofoils , analogous to wings ( airfoils ), used to propel and maneuver through the water with great speed and maneuverability (see Foil ). Swimming appendages with the digits still apparent, as in
1407-467: Is due primarily to its non-conventional flippers, which have large, irregular looking bumps called tubercles across their leading edges. The tubercles break up the passage of water, maintaining even channels of the fast-moving water, limiting turbulence and providing greater maneuverability. The foreflippers used by the pinnipeds act as oscillatory hydrofoils. Both fore and hind flippers are used for turning. A 2007 study of Steller's sea lion found that
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#17327874824771474-464: Is generally what is referred to as the "Canadian seal hunt". Hunting Canadian whitecoats has been banned since 1987. Since 2000, harp seals that are targeted during the hunt are often found to be less than a year old, known as "beaters". In 2006, the St. Lawrence hunt officially started on March 25 due to thin ice caused by the year's milder temperatures. Inuit living in the region hunt mainly for food and, to
1541-540: Is lubricated by lacrimal glands , to protect the eye from sea water damage. The lack of tear ducts to drain secretions to the nasal passages contribute to the harp seals "eye rings" on land. This can be an indication of the hydration level of the seal. On ice, the mother identifies her offspring by smell. This sense may also warn of an approaching predator . Underwater, the seal closes its nostrils, disabling its sense of smell. Its whiskers, called vibrissae , lie in horizontal rows on either side of its snout. They provide
1608-616: Is now thought that the monk seals , elephant seals , and Antarctic seals all evolved in the southern hemisphere, and likely dispersed to their current distributions from more southern latitudes. Bearded seal Hooded seal Ringed seal Baikal seal Caspian seal Spotted seal Harbor seal Grey seal Ribbon seal Harp seal Weddell seal Leopard seal Crabeater seal Ross seal Southern elephant seal Northern elephant seal Mediterranean monk seal Hawaiian monk seal Caribbean monk seal Otariidae ( eared seals ) Odobenidae ( Walrus ) In
1675-471: Is the only species in the genus Pagophilus . The mature harp seal has pure black eyes. It has a silver-gray fur covering its body, with black harp or wishbone -shaped markings dorsally . Adult harp seals grow to be 1.7 to 2.0 m (5 ft 7 in to 6 ft 7 in) long and weigh from 115 to 140 kg (254 to 309 lb). The harp seal pup often has a yellow-white coat at birth due to staining from amniotic fluid, but after one to three days,
1742-646: Is the preferred prey in both locales. Harp seals spend relatively little time on land compared with time at sea. They are social animals and can be quite vocal in groups. Within their large colonies, smaller groups with their own hierarchies form. Groups of several thousand form during pupping and mating season. Harp seals can live over 30 years in the wild. On the ice, pups call their mothers by "yelling," and "mumble" while playing with others. Adults "growl" and "warble" to warn off conspecifics and predators. Underwater, adults have been recorded using more than 19 types of vocalization during courting and mating. The harp seal
1809-525: Is widespread convergence at the gene level. Distinct substitutions in common genes created various aquatic adaptations, most of which constitute parallel evolution because the substitutions in question are not unique to those animals. When comparing cetaceans to pinnipeds to sirenians, 133 parallel amino acid substitutions occur. Comparing and contrasting cetaceans-pinnipeds, cetaceans-sirenians, and pinnipeds-sirenians, 2,351, 7,684, and 2,579 substitutions occur, respectively. Whales and their relatives have
1876-666: The Marine Mammal Protection Act in the United States . All three populations are hunted commercially, mainly by Canada , Norway , Russia and Greenland . In Canada, commercial hunting season is from November 15 to May 15. Most sealing occurs in late March in the Gulf of St. Lawrence , and during the first or second week of April off Newfoundland , in an area known as "the Front". This peak spring period
1943-1121: The Svalbard population found that this population predominantly eats krill, followed closely by polar cod ( Arctogladus glacialis) . Some individuals from the Greenland Sea sub-population have foraged in the Barents Sea alongside the White Sea sub-population during late summer and fall. Barents Sea harp seals eat mostly herring and polar cod but less krill or amphipods, likely because these seals usually dive deeper than such prey. Western North Atlantic harp seals forage both near and offshore of Newfoundland , most preferring such prey as Arctic cod ( Boreogadus saida) , capelin, Greenland halibut ( Reinhardtius hippoglossoides) and American plaice ( Hippoglossoides platessoides ). As in other populations and foraging areas, diet varies with distance from shore, with arctic cod comprising more of it nearshore and capelin more of it offshore. However, capelin
2010-408: The bauplan was refined through a secondary process of specialization. Evers et al. identified characters related to the pectoral girdle and forelimb that are related to the modification of sea turtle arms and hands into flippers. Key biomechanical features of flippers Fundamental traits for flipper movement Because of the specialization of flippers and their hydrodynamic constraints, it
2077-777: The coast of Labrador and Newfoundland , and the Gulf herd breeds near the Magdalen Islands in the middle of the Gulf of St. Lawrence . A second stock breeds on the " West Ice " off eastern Greenland. A third stock breeds on the "East Ice" in the White Sea , which is off the north coast of Russia below the Barents ea. Breeding occurs between mid-February and April, and varies somewhat for each stock. The three stocks are allopatric and do not interbreed. There are two recognised subspecies: Harp seals are strongly migratory ,
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2144-474: The coat turns white and stays white for 2–3 weeks, until the first molt . Adolescent harp seals have a silver-gray coat spotted with black. Harp seals are considered sexually dimorphic , as the males are slightly larger, and more decorated. Males weigh an average of 135 kg (298 lb), and reach a length up to 1.9 m (6.2 ft), while females weigh an average of 120 kg (260 lb) and reach up to 1.8 metres (5.9 ft). Males generally have
2211-480: The pelvis in such a way that they cannot bring them under their bodies to walk on them. They are more streamlined than fur seals and sea lions, so they can swim more effectively over long distances. However, because they cannot turn their hind flippers downward, they are very clumsy on land, having to wriggle with their front flippers and abdominal muscles . Phocid respiratory and circulatory systems are adapted to allow diving to considerable depths, and they can spend
2278-476: The sea turtles and the now-extinct plesiosaurs , mosasaurs , ichthyosaurs , and metriorhynchids . Usage of the terms "fin" and "flipper" is sometimes inconsistent, even in the scientific literature. However, the hydrodynamic control surfaces of fish are always referred to as "fins" and never "flippers". Tetrapod limbs which have evolved into fin-like structures are usually (but not always) called "flippers" rather than fins. The dorsal structure on cetaceans
2345-459: The tribe Lobodontini . Tribe Miroungini is composed of the elephant seals . The Monk seals ( Monachus and Neomonachus ) are all part of the tribe Monachini. Likewise, subfamily Phocinae (the "northern" seals) also includes three tribes; Erignathini ( Erignathus ) , Cystophorini ( Cystophora) , and Phocini (all other phocines). More recently, five species have been split off from Phoca , forming three additional genera. Alternatively
2412-463: The webbed forefeet of amphibious turtles and platypus , are considered paddles rather than flippers. For all species of aquatic vertebrates, swimming performance depends upon the animal's control surfaces, which include flippers, flukes and fins. Flippers are used for different types of propulsion, control, and rotation. In cetaceans, they are primarily used for control while the fluke is used for propulsion. The evolution of flippers in penguins
2479-571: The 1980s and 1990s, morphological phylogenetic analysis of the phocids led to new conclusions about the interrelatedness of the various genera. More recent molecular phylogenetic analyses have confirmed the monophyly of the two phocid subfamilies ( Phocinae and Monachinae). The Monachinae (known as the "southern" seals), is composed of three tribes; the Lobodontini, Miroungini, and Monachini. The four Antarctic genera Hydrurga , Leptonychotes , Lobodon , and Ommatophoca are part of
2546-409: The body surface as well as providing energy, most importantly for newly weaned pups. Flippers act as heat exchangers, warming or cooling the seal as needed. On ice, the seal can press its fore flippers to its body and its hind flippers together to reduce heat loss. They can also redirect blood flow from the periphery to minimize heat loss. The harp seal's eyes are large for its body size and contain
2613-411: The breeding site to use their stored energy to nurse pups. However, the common seal displays a reproductive strategy similar to that used by otariids , in which the mother makes short foraging trips between nursing bouts. Because a phocid mother's feeding grounds are often hundreds of kilometers from the breeding site, she must fast while lactating . This combination of fasting with lactation requires
2680-701: The course of a seal's lifetime. Young harp seals rely on a lanugo pelt from nursing all the way up to their weaning age. The insulating quality of this fur depends on its ability to keep a layer of air trapped inside or between the hairs. It takes a year for their blubber to develop and for their first-year pelage to grow. This transition from thick lanugo fur to blubber is important because lanugo fur does not insulate well in water. Adult harp seals primarily use blubber for insulation. Harp seals combine anatomical and behavioral approaches to managing their body temperatures, instead of elevating their metabolic rate and energy requirements. Their lower critical temperature
2747-489: The death of the mother's pup, since a female can only feed one pup. The pup's diet is so high in calories that it builds up a fat store. Before the pup is ready to forage, the mother abandons it, and the pup consumes its own fat for weeks or even months while it matures. Seals, like all marine mammals, need time to develop the oxygen stores, swimming muscles, and neural pathways necessary for effective diving and foraging. Seal pups typically eat no food and drink no water during
Harp seal - Misplaced Pages Continue
2814-407: The duration and intensity of movements without changing their sequence. Using criteria based on velocity and the minimum radius of turns, pinnipeds' maneuverability is superior to cetaceans but inferior to many fish. Marine mammals have evolved several times, developing similar flippers. The forelimbs of cetaceans, pinnipeds, and sirenians presents a classic example of convergent evolution . There
2881-444: The estimates from all areas resulted in an estimated total pup production of 746,500 (95% CI, 570,300-922,700). Due to their dependence on pack ice for breeding, the harp seal range is restricted to areas where pack ice forms seasonally. The western North Atlantic stock, which is the largest, is located off eastern Canada . This population is further divided into two separate herds based on the breeding location. The Front herd breeds off
2948-473: The family Phocidae ( / ˈ f oʊ s ɪ d iː / ). They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae . Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals , are mostly confined to polar , subpolar, and temperate climates. The Baikal seal is the only species of exclusively freshwater seal . The earliest known fossil earless seal
3015-479: The flipper refers solely to the forelimbs . In animals with four flippers, such as pinnipeds and sea turtles , one may distinguish fore- and hind-flippers , or pectoral flippers and pelvic flippers . Animals with flippers include penguins (whose flippers are also called wings ), cetaceans (e.g., dolphins and whales ), pinnipeds (e.g., walruses , earless and eared seals ), sirenians (e.g., manatees and dugongs ), and marine reptiles such as
3082-466: The hunt occurs on "the Front", most private monitors focus on the St. Lawrence hunt, due to its more convenient location. The annual quota off the coast of Greenland for 2017–2019 was set at 26,000 1+ animals, where two pups are equivalent to removing one 1+ animal. The total catches of harp seals were 2000 (including 1934 pups) in 2017, 2703 (including 1218 pups) in 2018, and 5813 (including 2168 pups) in 2019. The 2004 West Ice total allowable catch (TAC)
3149-447: The mother does not hunt, and loses up to 3 kilograms (6.6 lb) per day. Harp seal milk initially contains 25% fat (this number increases to 40% by weaning as the mother fasts) and pups gain over 2.2 kilograms (4.9 lb) per day while nursing, quickly thickening their blubber layer . During this time, the juvenile's "greycoat" grows in beneath the white neonatal coat, and the pup increases its weight to 36 kg (79 lb). Weaning
3216-480: The mother to provide large amounts of energy to her pup at a time when she is not eating (and often, not drinking). Mothers must supply their own metabolic needs while nursing. This is a miniature version of the humpback whales ' strategy, which involves fasting during their months-long migration from arctic feeding areas to tropical breeding/nursing areas and back. Phocids produce thick, fat-rich milk that allows them to provide their pups with large amounts of energy in
3283-421: The northwest population regularly moves up to 4,000 kilometres (2,500 mi) northeast outside of the breeding season; one individual was located off the north Norwegian coast, 4,640 kilometres (2,880 mi) east northeast of its tagging location. Their navigational accuracy is high, with good eyesight an important factor. They are occasionally found as vagrants , south of their normal range. In Great Britain ,
3350-733: The order Carnivora . Phocids have fewer teeth than land-based members of the Carnivora , although they retain powerful canines . Some species lack molars altogether. The dental formula is: 2–3.1.4.0–2 1–2.1.4.0–2 While otariids are known for speed and maneuverability, phocids are known for efficient, economical movement. This allows most phocids to forage far from land to exploit prey resources, while otariids are tied to rich upwelling zones close to breeding sites. Phocids swim by sideways movements of their bodies, using their hind flippers to fullest effect. Their fore flippers are used primarily for steering, while their hind flippers are bound to
3417-465: The origin of an early form of hyperphalangy in fully aquatic cetaceans about 35 million years ago. The process continued over time, and a very derived form of hyperphalangy, with six or more phalanges per digit, evolved convergently in rorqual whales and oceanic dolphins , and was likely associated with another wave of signaling within the interdigital tissues. Although toothed cetaceans have five digits, most baleen whales have four digits and even lack
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#17327874824773484-523: The period, although some polar species eat snow. The postweaning fast ranges from two weeks in the hooded seal to 9–12 weeks in the northern elephant seal. The physiological and behavioral adaptations that allow phocid pups to endure these remarkable fasts, which are among the longest for any mammal, remain an area of active study and research. Phocids make use of at least four different feeding strategies: suction feeding, grip and tear feeding, filter feeding, and pierce feeding. Each of these feeding strategies
3551-460: The principal control surfaces of cetaceans (whales, dolphins and porpoises) due to their position in front of the center of mass, and their mobility which provides three degrees of freedom . Flippers on humpback whales ( Megaptera novaeangliae ) have non-smooth leading edges, yet demonstrate superior fluid dynamics to the characteristically smooth leading edges of artificial wings, turbines and other kinds of blades. The whale's surprising dexterity
3618-456: The pups molt again, becoming "bedlamers". Juveniles molt several times, producing a "spotted harp", before the male adults' harp-marked pelt fully emerges after several years. In females, it does not emerge. Seals congregate annually on the ice to molt , pup and breed before migrating to summer feeding grounds. Their lifespan can be over 30 years. Global harp seal population estimates total around 9 million individuals. The number of pups born in
3685-493: The seal learns to swim. Pups begin to feed at 4 weeks of age, but still draw on internal sources of energy, relying first on energy stored in the body core rather than blubber. During this time the ice begins to melt leaving them vulnerable to polar bears and other predators including killer whales and large sharks. This fast can reduce their weight up to 50%. As many as 30% of pups die during their first year, due in part to their early immobility on land. Around 13–14 months old,
3752-511: The seals' prey. Harp seals can strand on Atlantic coasts, often in warmer months, due to dehydration and parasite load . In March 2020, a harp seal was spotted near Salvo, North Carolina . Harp seals often consume snow to stay hydrated, but in mild winters may not have enough available. Several centers are active in seal rescue and rehabilitation, including IFAW , NOAA , and the New England Aquarium . Harp seals are protected by
3819-413: The shock of a rapid change in environmental temperature and undeveloped blubber layers, the pup relies on solar heating, and behavioral responses such as shivering or seeking warmth in the shade or even water. Newborn pups weigh 11 kilograms (24 lb) on average and are 80–85 cm (31–33 in) long. After birth, the mother feeds only her own pup. During the approximately 12-day long nursing period,
3886-432: The skin. Phocids are able to divert blood flow to this layer to help control their temperatures. Unlike otariids, true seals do not communicate by 'barking'. Instead, they communicate by slapping the water and grunting. Phocids spend most of their time at sea, although they return to land or pack ice to breed and give birth. Pregnant females spend long periods foraging at sea, building up fat reserves, and then return to
3953-500: The sole mammals to have evolved hyperphalangy. Though the flippers of modern cetaceans are not correctly described as webbed feet, the intermediate webbed limbs of ancient semiaquatic cetaceans may be described as such. The presence of interdigital webbing within the fossils of semi-aquatic Eocene cetaceans was probably the result of BMP antagonists counteracting interdigital apoptosis during embryonic limb development . Modifications to signals in these tissues likely contributed to
4020-490: The spring and summer when seals forage along the pack ice in the Greenland Sea, most dives are less than 50 m. In the late fall and winter, dive depth has been found to increase, particularly in the Denmark Strait , where the mean dive depth was found to be 141 m. Lactating female harp seals spend about 80% of the time in the water and 20% of the time on the fast ice weaning or near their pups. However, almost half of
4087-400: The three monachine tribes have been evaluated to familiar status, which elephant seals and the Antarctic seals are more closely related to the phocines. Adult phocids vary from 1.17 m (3.8 ft) in length and 45 kg (99 lb) in weight in the ringed seal to 5.8 m (19 ft) and 4,000 kg (8,800 lb) in the southern elephant seal , which is the largest member of
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#17327874824774154-463: The time spent in the water is at the surface, well beyond what is expected to recover from dives. This behavior allows the mother harp seal to conserve energy and avoid the harsh conditions of the fast-ice while remaining near her pup. As with most phocids, she requires vast amounts of energy to ensure sufficient mass transfer to her growing, weaning pup. Harp seals remain within their aerobic dive limit for 99% of dives. Harp seal insulation changes over
4221-432: The traditional pupping area of the southern Gulf of St. Lawrence was greatly reduced, with an estimated pup production of only 18,300 (95% CI, 15,400-21,200 rounded to the nearest hundred). Another 13,600 (95% CI, 7,700-19,500) pups were born in the northern Gulf. An estimated 714,600 (95% CI, 538,800-890,400) pups were born off the northeastern coast of Newfoundland (Front); accounting for 96% of all pupping in 2017. Combining
4288-445: Was 15,000, almost double the sustainable catch of 8,200. Actual catches were 9,895 in 2004 and 5,808 in 2005. The 2004 White Sea TAC was 45,000. The catch was 22,474. Hunting has tremendously affected the population size of harp seals. Over the past 150 years, the harp seal population has fluctuated from over 9 million to as little as 1 million. The current population is estimated to be around 9 million. The Northwest Atlantic populations
4355-584: Was at the expense of their flying capabilities, in spite of evolving from an auk -like ancestor that could 'fly' underwater as well in the air. Form constrains function, and the wings of diving flying species, such as the murre or cormorant have not developed into flippers. The flippers of penguins became thicker, denser and smaller while being modified for hydrodynamic properties. Cetacean flippers may be viewed as being analogous to modern engineered hydrofoils, which have hydrodynamic properties: lift coefficient, drag coefficient and efficiency. Flippers are one of
4422-429: Was found to have decreased by at least 50 percent from 1952 to 1970 but nowadays, seal populations all are hunted under quotas and other restrictions. The Northwest population: The White Sea and West Ice populations: [REDACTED] Phocidae The earless seals , phocids , or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia . All true seals are members of
4489-421: Was thought that they were not used to significantly interact with the environment, unlike the legs of terrestrial tetrapods. However, the use of limbs for foraging is documented in marine tetrapods . Use of the flippers for foraging behavior is observed in marine mammals such as walruses , seals, and manatee, and even in reptiles such as sea turtles. Among turtles, observed behaviors include a green turtle holding
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