Harbor seal
Harbor seal | |
---|---|
A harbor seal off Lismore, Scotland | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Clade: | Pinnipedia |
Family: | Phocidae |
Genus: | Phoca |
Species: | P. vitulina
|
Binomial name | |
Phoca vitulina | |
Subspecies | |
P. vitulina concolor (DeKay, 1842) | |
Range of Phoca vitulina |
The harbor (or harbour) seal (Phoca vitulina), also known as the common seal, is a
Harbor seals are brown, silvery white, tan, or gray, with distinctive V-shaped nostrils. An adult can attain a length of 1.85 m (6.1 ft) and a mass of up to 168 kg (370 lb). Blubber under the seal's skin helps to maintain body temperature. Females outlive males (30–35 years versus 20–25 years). Harbor seals stick to familiar resting spots or haulout sites, generally rocky areas (although ice, sand, and mud may also be used) where they are protected from adverse weather conditions and predation, near a foraging area. Males may fight over mates under water and on land. Females bear a single pup after a nine-month gestation, which they care for alone. Pups can weigh up to 16 kg (35 lb) and are able to swim and dive within hours of birth. They develop quickly on their mothers' fat-rich milk, and are weaned after four to six weeks.
The global population of harbor seals is 350,000–500,000, but the freshwater subspecies Ungava seal in Northern Quebec is endangered.[1] Once a common practice, sealing is now illegal in many nations within the animal's range.
Description
Individual harbor seals possess a unique pattern of spots, either dark on a light background or light on a dark. They vary in colour from brownish black to tan or grey; underparts are generally lighter. The body and flippers are short, heads are rounded. Nostrils appear distinctively V-shaped. As with other true seals, there is no
Population
There are an estimated 350,000–500,000 harbor seals worldwide.
Seals in the United Kingdom are protected by the 1970
Subspecies
The five proposed subspecies of Phoca vitulina are:
Image | Subspecies | Common Name | Distribution |
---|---|---|---|
P. v. vitulina (L., 1758) | Eastern Atlantic common seals | Europe and western Asia. | |
P. v. concolor (DeKay, 1842) | Western Atlantic common seals | inhabit eastern North America. The validity of this subspecies is questionable, and not supported by genetic evidence. They might be part of the Eastern Atlantic subspecies.[6] | |
P. v. mellonae (Doutt, 1942) | Ungava seals (Lacs des Loups Marins seals) | found in eastern Canada in fresh water | |
P. v. richardsi (Gray, 1864) | Pacific common seals | western North America. | |
Phoca vitulina stejnegeri (J. A. Allen, 1902) | Insular seals | Eastern Asia. Currently not recognised as a separate subspecies, but part of P. v. ricardsi[7] |
Habitat and diet
Harbor seals prefer to frequent familiar resting sites. They may spend several days at sea and travel up to 50 km in search of feeding grounds, and will also swim more than a hundred miles upstream into fresh water in large
Behavior, survival, and reproduction
Harbor seals are solitary, but are gregarious when hauled out and during the breeding season, though they do not form groups as large as some other seals. When not actively feeding, they
Birthing of pups occurs annually on shore. The timing of the pupping season varies with location,[14] occurring in February for populations in lower latitudes, and as late as July in the subarctic zone. The mothers are the sole providers of care, with lactation lasting 24 days.[15] The single pups are born well developed, capable of swimming and diving within hours. Suckling for three to four weeks, pups feed on the mother's rich, fatty milk and grow rapidly; born weighing up to 16 kilograms, the pups may double their weight by the time of weaning.
Harbor seals must spend a great deal of time on shore when molting, which occurs shortly after breeding. This onshore time is important to the life cycle, and can be disturbed when substantial human presence occurs.[16] The timing of onset of molt depends on the age and sex of the animal, with yearlings molting first and adult males last.[17] A female mates again immediately following the weaning of her pup. Harbor seals are sometimes reluctant to haul out in the presence of humans, so shoreline development and access must be carefully studied in known locations of seal haul out.[citation needed]
In comparison to many pinniped species, and in contrast to otariid pinnipeds, harbor seals are generally regarded to be more vocally reticent. However, they do utilize non-harmonic vocalizations to maintain breeding territories and to attract mates during specified times of year,[18] and also during mother and pup interactions.[19]
Annual survival rates were calculated at 0.91 for adult males,[11] and 0.902 for adult females.[20] Maximum age for females was 36 and for males 31 years.[11]
In North America
Pacific Coast
The California population of subspecies P. v. richardsi amounted to about 25,000 individuals as of 1984. Pacific harbor seals or California harbor seals are found along the entire Pacific Coast shoreline of the state. They prefer to remain relatively close to shore in subtidal and
Considerable scientific inquiry has been carried out by
Although some of the largest harbor seal pupping areas are found in California, they are also found north along the Pacific Coast in Oregon, Washington, British Columbia and Alaska. Large populations move with the season south along the west coast of Canada and may winter on the islands in Washington and Oregon. Pupping is known to occur in both Washington and Oregon as of 2020. People are advised to stay at least 50m away from harbor seals that have hauled out on land, especially the pups, as mothers will abandon them if there's too much human activity nearby.[30]
Atlantic Coast
Historically, the range of the harbor seal extended from the mouth of the St. Lawrence River and Greenland to the sandy beaches of North Carolina, a distance of well over a thousand miles (greater than 1600 km.) Evidence of their presence in these areas is consistent with both the fossil record as well as a few landmarks named for them during colonization: Robbin's Reef, off of Bayonne, New Jersey, gets its name from the Dutch word robben, meaning "seals". On the border between Canada and the US is an island known as Machias Seal Island, a place where today the harbor seal will occasionally visit but is now a sanctuary for puffins. Over the course of hundreds of years, however, the seal was wiped out steadily by being shot on sight by fishermen and by massive pollution. The evidence for this is found in documents all along the coast of New England which put a bounty on the head of every seal shot, as well as the accounts of harbormasters. New York City, when it was founded in the 1640s, was founded on top of an enormous estuary teeming with life that included the harbor seal. Oil in the 1800s started the process of pollution that was later compounded by even more toxic 20th century chemicals that included PCB's and dioxin. By the time of the 1972 Clean Water Act, New York Harbor was almost dead-almost no living thing could survive in it.[31] Approximately 300 miles to the north, Boston Harbor was equally polluted. Raw sewage had been dumped in the harbor since the late 1800s and the stench of fecal matter in the Charles River was overpowering, as evidenced by the song "Dirty Water" by the Standells, written in 1966. Flatfish, abundant in the area, had enormous tumors in their livers by the 1980s and the harbor seal was long gone, shot to oblivion.[32]
As of 2020, however, the seals have returned. They never were extirpated from Canada and certain pockets of the Maine coast, and thus an important mother population was created from whence the species could reclaim the home of their ancestors. Currently, they are sighted as far south as the barrier islands of North Carolina on a regular basis,[33] with Massachusetts being the southernmost point of known pupping areas along the Atlantic Coast.[34] Harbor seals move south from eastern Canadian waters to breed along the coast of Maine, Cape Cod, and the South Shore in Massachusetts in May and June, and return northward in fall. Others will head south from these areas to "vacation" in warmer waters, particularly young seals unable to compete with adults for food and territory; they do not return north until spring.
One park ranger in New York City, which is dead center of its West Atlantic range, says that "New York is like their Miami resort."
Notable individuals
- Andre, rescued and trained by his owner Harry Goodridge, he became an iconic figure in his hometown of Rockport, Maine.
- Hoover, also rescued from a Maine harbor. Hoover became famous for his ability to imitate human speech, something not observed in any other mammal.
- Popeye, the official seal of Friday Harbor, Washington, notable for her common sightings up until 2019, when she was presumed to have died. She was identified and named for her cloudy left eye. There is a statue of her in the Port of Friday Harbor.
- Freddie, a seal pup commonly spotted along the Thames in central London. Named after Freddie Mercury due to his bushy whiskers and playfulness. Freddie was known to travel unusually far into London from the Thames Estuary, and was often sighted as far west as Hammersmith. On 21 March 2021 he had to be put down after he was violently mauled by an out-of-control dog.[41]
See also
- Conservation of Seals Act 1970 (in the UK)
- Marine Mammal Protection Act (in the United States)
- Wadden Sea Agreement(in the Netherlands, Germany and Denmark)
References
Footnotes
- ^ . Retrieved 12 November 2021.
- ^ Linnæus, Carl (1758). Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I (in Latin) (10th ed.). Holmiæ (Stockholm): Laurentius Salvius. p. 38. Retrieved 23 November 2012.
- ISBN 978-0-7894-7764-4.
- S2CID 84812505.
- ^ "Seals". GOV.UK. Retrieved 2022-02-08.
- .
- ^ Society for Marine Mammalogy (13 November 2016). "Committee on Taxonomy. List of marine mammal species and subspecies". Society for Marine Mammalogy. Retrieved 6 September 2021.
- ^ Photographic evidence
- ^ Burns, J.J. (2002). Harbor seal and spotted seal Phoca vitulina and P. largha. In: W.F. Perrin, B. Wursig and J.G.M. Thewissen (eds), Encyclopedia of Marine Mammals Academic Press. pp. 552–560.
- ^ "Harbour seal kills and eats duck" Archived 2017-10-22 at the Wayback Machine, Tetrapod Zoology, 6 march 2008.
- ^ ISSN 0078-5326.
- .
- doi:10.1139/z02-088.
- ^ Temte, J. L. (1994). Photoperiod control of birth timing in harbour seal (Phoca vitulina). Journal of Zoology (London) 233: 369–384.
- JSTOR 1312894
- ^ Patrick Sullivan, Gary Deghi and C.Michael Hogan, Harbor Seal Study for Strawberry Spit, Marin County, California, Earth Metrics file reference 10323, BCDC and County of Marin, January 23, 1989.
- S2CID 25505946.
- PMID 28372144.
- doi:10.1139/z88-138.
- .
- ^ Newby, T.C. (1978). Pacific Harbor Seal pp 184–191 in D. Haley, ed. Marine Mammals of Eastern North Pacific and Arctic Waters, Pacific Search Press, Seattle WA.
- ^ "Pinniped Management Plan" (PDF). File.lacounty.gov. Retrieved March 21, 2022.
- ^ "How to safely spot sea lions and seals along the Southern California coast". Scpr.org. August 22, 2011.
- ^ "Santa Barbara - Stranded Marine Mammals". Santabarbaraca.gov. 6 June 2022.
- ^ "Why sharks and seals are coming to Los Angeles and Long Beach ports". Presstelegram.com. December 11, 2016.
- ^ "Harbor Seals: At Home in the Bay". Baykeeper.org. August 2013.
- ^ "Forget Pier 39: Harbor seals find spot in East Bay". Mercurynews.com. August 9, 2016.
- herpesvirus-1 in rehabilitating and free-ranging Pacific harbor seals (Phoca vitulina) in California. Veterinary Microbiology; 103:131–141.
- ^ "The Marine Mammal Center". The Marine Mammal Center. Retrieved 2019-07-02.
- ^ "Public urged to refrain from approaching seal pups on local beaches". Chinookobserver.com. 21 May 2020.
- ^ a b "Why These Seals Left New York—and Why They Came Back | Lenora Todaro". Catapult.co. March 20, 2019.
- ^ Moore, Michael (14 January 2019). "Boston "Harbor of Shame" Successfully Ends 30-Year Cleanup". Inverse.com. Retrieved 21 March 2022.
- ^ Horan, Jack (February 17, 2016). "Seals Swim to NC, Visit the Outer Banks". News and Observer. Retrieved October 6, 2020.
- ^ "Cape Cod Seals". Coastalstudies.org.
- ^ Spitznagel, Eric (2019-08-10). "Why New York harbor is the cleanest it's been in 110 years". New York Post. Retrieved 2020-10-06.
- ^ Newman, Andy (March 25, 2006). "Swimmers from the North Delight Scientists and Sightseers". The New York Times.
- ^ Archived at Ghostarchive and the Wayback Machine: "Seals Making A Comeback In NYC Waters". YouTube.
- ^ "What To Do If You See An Adorable Seal Wandering Around NYC". Gothamist.com. 2020-01-15. Retrieved 2020-10-06.
- ^ "Hundreds of seals are now calling the waters around NYC home". Ny1.com. Retrieved 2020-10-06.
- ^ "A Vision for Menhaden: Supporting Anglers, Wildlife, and Businesses From Florida to Maine". Pew.org. 9 November 2017. Retrieved 2020-10-06.
- ^ "Freddie the seal death: Dog owner sought by police after Thameside attack". BBC News. March 23, 2021. Retrieved August 10, 2022.
Bibliography
- van den Toorn, Jaap (1999-09-21). "Harbor seals". Jaap's Marine Mammal Pages. Archived from the original on 2006-03-11. Retrieved 2006-06-26.
- California Wildlife, Volume III, California Department of Fish and Game, Apr., 1990.
- CRC Handbook of ISBN 0-8493-0839-9
- Hewitt, Joan (2002). A Harbor Seal ISBN 1-57505-166-4
External links
- "Phoca vitulina". Integrated Taxonomic Information System. Retrieved 23 March 2006.
- Harbor Seals at Stanford University
- Images and movies of the Harbor seal—ARKive
- photos of harbor seal haulouts from Japan to France—SealWatch archive
- Harbor Seal—Marine Mammal Center
- North American Mammals: Phoca vitulina—Smithsonian Institution