Gray Seal
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| Grey Seal[1] | |
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| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Suborder: | Caniformia |
| Superfamily: | Pinnipedia |
| Family: | Phocidae |
| Genus: | Halichoerus Nilsson, 1820 |
| Species: | H. grypus |
| Binomial name | |
| Halichoerus grypus (Fabricius, 1791) |
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| Approximate Gray Seal range (in blue) | |
The Grey Seal (Halichoerus grypus, meaning "hooked-nosed sea pig") is found on both shores of the North Atlantic Ocean. It is a large seal of the family Phocidae or "true seals". It is the only species classified in the genus Halichoerus. Its name is spelled Gray Seal in the US, it is also known as Atlantic Grey Seal and the Horsehead Seal[3].
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[edit] Appearance
It is a medium sized seal, with the bulls reaching 2.5–3.3 m long and weighing up to 300 kg; the cows are much smaller, typically 1.6–2.0 m long and 100–150 kg weight. It is the typical seal of the northern and western coasts, the Common Seal being more often seen off southeastern coasts. It is distinguished from Common Seal by its straight head profile with nostrils that are well apart, and fewer spots on its body. Bull Grays have larger noses and a more convex profile than Common Seal bulls. Males are often darker than females, with lighter patches and often scarring around the neck. Females are silver grey to brown with dark patches.
[edit] Ecology
In Great Britain and Ireland, the Gray Seal breeds in several colonies on and around the coasts; notably large colonies are at Donna Nook (Lincolnshire), the Farne Islands off the Northumberland Coast (about 6,000 animals), North Rona off the north coast of Scotland, Lambay Island off the coast of Dublin and Ramsey Island off the coast of Pembrokeshire.
In the Western North Atlantic, the Grey Seal is typically found in large numbers in the coastal waters of Canada and south to about New Jersey in the United States. In Canada, it is typically seen in areas such as the Gulf of St. Lawrence, Newfoundland and the Maritimes, and Quebec. The largest colony in the world is at Sable Island. In the United States it's found year round off the coast of New England, in particular Maine and Massachusetts, and slightly less frequently in the Middle Atlantic States. Its natural range extends south to Virginia.
During the winter months it can be seen hauled out on the rocks, islands, and shoals not far from shore, like great gray bananas in the sun, and occasionally coming ashore to rest. In the spring the recently weaned pups and yearlings occasionally strand on beaches after becoming "lost."
[edit] Diet
The Grey Seal feeds on a wide variety of fish, mostly benthic or demersal species, taken at depths down to 70 m (230 ft) or more. Sand eels (Ammodytes spp) are important in its diet in many localities. Cod and other gadids, flatfish, herring[citation needed] and skates are also important locally. However, it is clear that the Gray Seal will eat whatever is available, including octopus and lobsters.[citation needed] The average daily food requirement is estimated to be 5 kg (11 lb), though the seal does not feed every day and it fasts during the breeding season.
[edit] Reproduction
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The pups are born in autumn (September to November) in the eastern Atlantic and in winter (January to February) in the west, with a dense, soft silky white fur; at first they are small and shrivelled-looking, but they rapidly fatten up to look like over-filled barrels, from the extremely fat-rich milk they receive from their mothers. Within a month or so, they shed the pup fur and grow the dense waterproof adult fur, and soon leave for the sea to learn to fish for themselves. In recent years, the number of Gray Seals has been on the rise in the west and in Canada there have been calls for a seal cull. However this does not appear to be coming to fruition any time soon.
[edit] Status
In the United States Gray Seal numbers are increasing rapidly. Up until 1962, Maine and Massachusetts had bounties on seals so that only a few isolated colonies of Gray Seals remained in Maine. Then in 1972 Congress passed the Marine Mammal Protection Act that prevented harming or harassing seals, and Gray Seal populations rebounded. For example there is a large breeding colony near Cape Cod, Massachusetts, where pups rebounded from a handful in 1980 to more than 2,000 in 2008. By 2009, thousands of Gray Seals there had taken up residence on or near popular swimming beaches when Great White Sharks started hunting them close to shore.[4] Also Gray Seals are seen increasingly in New York and New Jersey waters, and it's expected that they will establish colonies further south.
In the UK seals are protected under the Conservation of Seals Act 1970, however it does not apply to Northern Ireland. In the UK there have also been calls for a cull from some fishermen, claiming that stocks have declined due to the seals.
[edit] Subspecies
There are two recognized subspeices of this seal:[1]
- Halichoerus grypus grypus
- Halichoerus grypus macrorhynchus
[edit] References
- ^ a b Wozencraft, W. C. (16 November 2005). Wilson, D. E., and Reeder, D. M. (eds). ed. Mammal Species of the World (3rd edition ed.). Johns Hopkins University Press. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=14001036.
- ^ Thomspon, D. & Harkonen, T. (2008). Halichoerus grypus. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 29 January 2009.
- ^ Mowat, Farley, Sea Of Slaughter, Atlantic Monthly Press Publishing, First American Edition, 1984.
- ^ Once again, coastal waters getting seals’ approval Boston Globe, October, 2009.
[edit] External links
- BBC Wales Nature: Grey Seal video clips
- Grey Seals on pinnipeds.org : http://www.pinnipeds.org/species/grey.htm
- ARKive - images and movies of the grey seal (Halichoerus grypus)
- Grey Seal Conservation Society (GSCS) http://www.greyseal.net
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