Harp Seal


Wikipedia Article
Copyright Notice: This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Harp Seal".

The Harp Seal (Phoca groenlandica; syn. Pagophilus groenlandicus) is a species of earless seal native to the northernmost Atlantic Ocean and adjacent parts of the Arctic Ocean.

Features
It is somewhat larger than the Common Seal, growing to 155–220 cm long and with a weight of 115–180 kg; males are distinctly larger than females. Adult males are creamy white overall, with a dark chocolate brown head and a broad dark chocolate brown U-shaped pattern on their back, running across the shoulders and down each flank to near the base of the tail; the pattern is often slightly asymmetrical and irregular, with dark brown spots extending onto the white parts. Adult females have a similar but less distinct pattern, with the brown being paler and greyer. Immatures up to two to three years old are pale grey, variably spotted with darker grey. The flippers are white or pale grey, with five stout claws on each fore flipper. The tail is short, 10–15 cm long. The penis pump on adults is 2 cm long, dense, stiff and velvety; the skin is roughly the same colour as the fur, whitish-grey under the white fur, and dark brown under the brown fur. The vibrissae are numerous on the muzzle, the longest about 12 cm long. The newborn pups are all white except for a black nose and eyes, which helps them blend in with the snow. Puberty is reached at 5–7 years, and the maximum lifespan is more than 30 years.

 
 
Structurally, it resembles the Common Seal closely, and it is now usually included in the same genus Phoca, rather than separated into its own genus Pagophilus as was often done in older texts.

Population
Harp Seals separate into three populations according to their breeding locations; the White Sea, the West Ice between Jan Mayen and Greenland, and the Northwest Atlantic near Newfoundland, Canada. Seals breeding in the Northwest Atlantic represent the largest population and are genetically different from seals breeding in the two other areas, which have not been proven genetically different from each other. They are however visually indistinguishable, and a degree of mixing between the populations occurs.

The Northwest population
There are no reliable estimates of the size of Northwest Atlantic population when commercial hunting began in the early 1800s. Several simulation models estimated virginal populations to be in the 3 to 4 million range. It is considered that the population recovered to about 3 million at the end of World War II, but subsequently declined by 50–66% between 1950 and 1970 due to commercial hunting in Canada. Quotas and other conservation measures since then have enabled the population to nearly triple in size to 5.2 million according to a peer-reviewed survey in 1999.

White Sea and West Ice populations
Mature females usually give birth to one pup in March/April each year. The pups are born within well defined areas in the drift ice in the White Sea or in the area between Jan Mayen and East Greenland (the West Ice population). Harp Seals migrate in search for food over large areas in the Barents Sea, the Norwegian Sea, the Greenland Sea and the Denmark Strait.

The population size in 2000 was estimated to be more than 300,000 in the White Sea and 361,000 in the West Ice.

The annual prey consumption was in 2000 estimated to about 3.5 million tonnes in the White Sea area (Nilssen et al 2000).

Breeding
Each year, mature females (5-6 years old) give birth to a single pup, typically in late February. Pups weigh approximately 10 kg and are 80–85 cm long. Immediately after giving birth, the mother smells her offspring, and from that point on will only ever feed her own pup, whose scent she remembers. Harp Seal milk contains up to 50% fat, so pups gain over 2 kg per day when nursing, which lasts roughly 12 days. During this time the mother does not eat, and will lose up to 3 kg per day of body weight. Weaning is abrupt; the mother simply leaves and never comes back. The stranded pup will cry at first, and then become very sedentary to conserve body fat.

Pups are unable to swim or find food until they are about 25 days old, leaving them very vulnerable to Polar Bears and humans during this time. Due in part to the period of helplessness as infants, and to the long time it takes them to become proficient swimmers, as many as 30% of pups fail to survive their first year. Also, although it is not legal to catch seals using nets, thousands of seals are inadvertently killed in commercial fishing nets every year.

 
 
When the mother weans its pup, mature males (6–7 years old) roam around breeding with the females promiscuously. While courtship begins on the ice, the actual mating takes place in the water. Harp Seals have delayed implantation, meaning the fertilized egg becomes an embryo, but does not implant in the uterus right away. The embryo will float around for about three and a half months before implanting and beginning to grow. This allows all the females to give birth within a very small time window each year, when the ice pack is available for giving birth and raising their young.

Migration and vagrancy
Harp Seals are strongly migratory. The northwest population regularly moves up to 4,000 km northeast outside of the breeding season; one tagged individual of this population was recovered at sea off the north Norwegian coast, 4,640 km east-north-east of its tagging location. Their navigational accuracy is very high, with good eyesight being an important factor.

They are occasionally found as a vagrant south of its normal range. In Great Britain, a total of 31 were recorded between 1800 and 1988, with one subsequently, on Lindisfarne in Northumberland in September 1995.

One recorded in the Shetland Islands in 1987 was linked to a mass movement of Harp Seals into Norwegian waters; by mid-February 1987, 24,000 were reported drowned in fishermen's nets and perhaps 300,000 (about 10% of the world population) had invaded fjords as far south as Oslo. The animals were in an emaciated condition and this was believed to be the result of food shortages, likely due to over-fishing by humans.

Diet
Harp Seals eat a wide variety of fish and other sea creatures, and their diet seems to vary during different stages of life. Since reporting of the stomach contents of killed seals began in 1941, at least 67 species of fish and 70 species of invertebrates have been found to be part of the Harp Seal's diet. After the Canadian cod collapse many French fishermen and politicians blamed Harp Seals for the destruction and hindering the recovery of the North-West atlantic cod population. Although cod is a major contribution to the diet, most of the cod eaten are arctic cod and not the commercial atlantic ones. The ratio is about 36:10 although the total tonnage of cod is around 200,000 tonnes. Although the effect of recorded population levels of Harp Seals on the recovery of the atlantic cod stocks has been disputed, the evidence is enough that most scientists accept that cod populations are now in a seal predator trap. It is widely accepted that Harp Seals did not cause the collapse. However, a strong case can be made that both Harp and Hooded Seals contributed to that collapse, as did other factors such as environmental change and marine community shifts. The main issue with the cod stocks is that if the hunting was to stop, the population would grow and therefore cause total prey consumption to increase. Even with heavy hunting, from 1990 to 1999 there was a 800,000-tonne (32%) increase in fish consumption by seals. If the hunt was to stop, it is believed that the population would sky-rocket and within a few years it would double the consumption rate. The Harp Seal is at the top of its food chain and has few natural predators to keep its population at bay. For more information, view the Northwest Atlantic Harp Seals Stock Status Report 2000 from the Canadian Government.

Predators
Natural predators include Polar Bear, Orca, sharks, and in some areas Walruses.

Seal hunting
All three populations are hunted commercially, mainly by Canada, Norway, Russia and Greenland. In hunting terminology, Harp Seals are often given different names according to their age: In Canada, the season for the commercial hunt is from November 15 to May 15. The majority of sealing, however, 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 is generally what is referred to as the "Canadian Seal Hunt". In 2006, the St. Lawrence seal hunt officially started on March 25. This date was initially uncertain, due to thin ice conditions caused by the year's milder temperatures. Inuit people living in the region hunt them mainly for sport and to a lesser extent, commercial reasons.

In 2003, the three-year quota granted by the Department of Fisheries and Oceans was increased to a maximum of 975,000 animals, with a maximum of 350,000 animals in any two consecutive years. In 2006, 325,000 Harp Seals, as well as 10,000 Hooded Seals and 10,400 Grey Seals were killed. An additional 10,000 animals are allocated for hunting by natives.

The Canadian seal hunt is monitored by the Canadian Government. However, although approximately 70% of Canadian seals killed are killed on "The Front", the vast majority of private monitors focus on the St. Lawrence hunt, due to its more convenient location.

The 2006 St. Lawrence leg of the hunt was officially closed on April 3, 2006. Sealers had exceeded the quota by 1,000 animals by the time the hunt was closed.

 Top
This article is from Wikipedia, a user-contributed encyclopedia.
It may not have been reviewed by professional editors. (Please see the full Wikipedia disclaimer).


Endangered Species of Our Planet



Donate, Adopt, Get Involved

EEC Conservation Directory
Donate

Mailing List

Would you like to receive a notice and link when the new Creature Feature is posted?

Enter your e-mail address below:

 
HTML   Text-only

Coloring

Are you inspired by endangered animals? Check out our coloring pages!
color endangered creatures