Distribution and Habitat
Grey seals can be separated into three distinct populations based on their distribution, size and breeding season: Northwest Atlantic (from northern Labrador to Nantucket, Massachusetts), Northeast Atlantic (from northern Norway to the middle of France, and from northern Norway to the White Sea), and Baltic (northeastern Gulf of Finland, off southeastern Sweden, the archipelago separating the Gulf of Bothnia from the Baltic proper and the Soviet Baltic). Most of the Northwest stock gives birth on ice in the Northumberland Strait, and on sandy Sable Island. The majority of Northeast pupping occurs around the British Isles especially off the northeast coast of Scotland. Smaller colonies also exist in France, the Netherlands, Germany, the Faroe Islands, Norway and Russia.
Grey seal males are considerably larger than the females. Of the three populations, the Northwest Atlantic grey seals are the largest, with males measuring up to 2.3 m and weighing 300-350 kg, and females measuring up to 2.0 m and 150-200 kg. The Northeast Atlantic grey seals appear smaller; males average about 2m in length and weigh 170-310kg; females average 1.8 m and 103-180 kg. Male grey seals are characterized by the long, arched, horse-like, or "Roman", nose, heavy shoulders and thick, folded skin of the neck region. The females nose is similar but shorter and narrower. The coat of mature males is dark brown, grey or black with lighter blotches on the neck and flanks. The female is lighter in colour, with dark spots on a grey, tan or yellowish background. In the water, grey seals tend to be solitary or in small groups, but on land they are gregarious and can be found hauled out with harbour seals in areas where the two species coexist. Each population breeds at a different time and variation within the populations also exist. Pups weigh 11-20 kg at birth and are weaned at about 3 weeks of age. At this time, mating occurs between waiting males and receptive females. Grey seals feed on a wide variety of fish, crustaceans and cephalopods. The diet varies with location, season and prey availability. Fasting occurs during the breeding and moulting seasons.
The Northwest Atlantic population is estimated at 85,000-110,000 animals. In1990, the Northeast population consisted of about 102,000 grey seals, 85,000 of them found off the coast of Britain. The Baltic grey seal is thought to number between 2,000 and 3,000 animals.
Threats to the Species
In the past, grey seals have been killed for their skins, meat and oil in the UK, Iceland, Canada and the Baltic. Bounties and cull programs have been initiated by different countries over the last century. Today, grey seals are rarely used as a resource but are considered a pest in certain areas; culling initiatives and directed takes by fishers continue to be initiated because of perceived competition for commercial fish species, gear damage and as hosts of codworm (Pseudoterranova decipiens). Grey seals in the Baltic and White Sea appear to be adversely affected by pollution and entanglement in fishing gear.
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Reeves R.R. et al. 1992. The Sierra Club handbook of seals and sirenians. Sierra Club Books,359pp. San Francisco.