Grey Seal
(Halichoerus grypus)

IUCN STATUS (2010) - LEAST CONCERN

Baltic Sea grey seal - ENDANGERED

 

Distribution and Numbers
Grey seals are found on both sides of the north Atlantic Ocean, separated into three distinct populations. The western Atlantic population is centred in the Canadian Maritime provinces, and is distributed from north Labrador down to New England, individuals occasionally wandering as far south as Virginia. The eastern Atlantic population is found mostly around the coasts of the United Kingdom and Ireland, as well as on the coasts of the Faroe Islands, Iceland, Norway, and northwestern Russia as far as the White Sea. Smaller groups are also found on the French, Dutch and German coasts, and wandering individuals have been found as far south as Portugal. A third population of grey seals, quite distinct from the eastern Atlantic population, is located in the Baltic Sea.		 Halichoerus grypus - Image 1

Photo: Salko de Wolf,
Ecomare
The total number of grey seals in the western Atlantic population is unknown but thought to be at least 150,000, the vast majority of these forming the Sable Island and the Gulf of St. Lawrence populations. There are also currently estimated to be about 130,000-140,000 grey seals in the eastern Atlantic population, and about 7,500 in the Baltic Sea, producing an estimated world-wide total of around 290,000-300,000 grey seals.
Status
Although large-scale commercial hunting of grey seals has not taken place in recent years, it was revealed in 1998 that a sealers' organisation in Nova Scotia had asked the Canadian government for permission to kill 25,000 grey seals a year for the next three years and to market the resulting seal products. The Canadian Fisheries Resource Conservation Council also called in 1999 for an experimental commercial seal hunt of up to 20,000 grey seals on Sable Island. The Canadian government has permitted the killing of a few hundred grey seals per year in areas other than Sable Island since 1999, and has announced that additional proposals for grey seal hunts will be considered. It was also reported that the Norwegian government decided to permit a hunt for 400 grey seals between Lista and Stad on the coast of Western Norway during 2000, even though the authorities do not know how many grey seals there are in the area and it is probable that the numbers vary widely. The Norwegian government commented that the hunt was considered to be an experiment in which interest in hunting the seals would be determined.
There are frequent calls for culls of grey seals, particularly in Canada, the United Kingdom and Ireland, by fishing interests who claim that seal predation is the reason behind reduced fish stocks and that a reduction in the number of grey seals would result in an increase in the amount of commercially landed fish. There is however no scientific evidence to support this argument. Grey seals can act as hosts to the codworm parasite, and calls have also been made to cull grey seals by those who believe that such a cull would reduce the codworm infestation in cod and flatfish stocks. Local culls have taken place and bounties on grey seals have been offered in recent years in several countries such as Canada, Iceland and Norway in an attempt to reduce grey seal numbers. The last organised fisheries-related cull in the United Kingdom took place in 1983, the series of culls in that country being terminated due to public opinion, and the Canadian bounty ended in 1992.
Grey seals on both sides of the Atlantic are killed through fisheries conflicts, the shooting of seals to prevent seal damage to nets, traps and catch being common in both fisheries and fish farming. This form of shooting is legal in most countries within the grey seal's range. Fishermen and fish farmers in the United Kingdom do not need to report the shooting of seals under the "Fisheries Defence Clause" of the Conservation of Seals Act and therefore the scale of such killing in the U.K. is uncertain. Official statistics show that more than 60 grey and harbour seals (Phoca vitulina) were legally shot under licence by Scottish fishery boards during the year 2000, the most in more than a decade. Conservationists however say that the official figures hide the fact that a very large number of both species, estimated by some organisations as totalling several thousand seals, are shot under the Fisheries Defence Clause each year in Scotland. Conservation groups are attempting to promote the development and use of humane non-lethal seal deterrence methods, including effective anti-predator nets on fish farms. Some politicians and fishery interests have called for grey seals to be darted with contraceptives but the general consensus is that this method is fraught with technical and practical difficulties, conservation groups also arguing that it is a smoke screen for underlying issues such as overfishing.
Illegal shooting of grey seals is known to take place throughout their range, a recent much-publicised example being the shooting of 25 whitecoat pups at a breeding rookery in the Scottish Orkney Islands in 1996. Concern has also been expressed about the effects of marine pollution, particularly contaminants such as organochlorines, on the health of grey seals. The species can also be affected by oil spills. Moulting grey seals in Shetland, for example, showed signs of acute respiratory distress, possibly caused by the ingestion of hydrocarbons, after the Braer oil spill in 1993. Frequent oil contamination of grey seals caused by drifting marine pollutants is a severe problem in the Froan breeding area off central Norway, annual surveys there showing that 30-60% of pups become oil-fouled during their first month of life. Disturbance and entanglement in marine debris are additional problems encountered throughout the grey seal's range. Hundreds of grey seals were killed by the epizootic of Phocine Distemper Virus that affected mainly harbour seals in 1988, scientists also noting a 12% reduction in grey seal pup production as a result of the virus. Grey seals have been killed by being trapped in the intake pipes of power plants in the United States.
An average of 75 grey seals are estimated to have been killed each year by entanglement in nets of the U.S. Northeast multispecies sink gillnet fishery in the Gulf of Maine and southern New England between 1994 and 1998. In Canada an unknown number of grey seals are entangled in nets of groundfish gillnet fisheries in Newfoundland and Labrador, the Gulf of St. Lawrence and the Bay of Fundy, and also in nets of the Atlantic Canada salmon gillnet fishery. A number of grey seals have also been entangled in nets of the Spanish deep water trawl fishery off Canada. The overall numbers of seals entangled decreased after the Greenland salmon gillnet and Atlantic Canada cod trap fisheries were ended in 1993. Entanglement of grey seals in the nets of monkfish fishermen in Cornwall, England, is a particular problem affecting the viability of the small population there, one scientist having estimated in 2000 that the annual death toll of grey seals entangled in the area's monkfish nets is higher than the number of grey seals born there each year.
The first few months of 2001 saw reports of a large increase in sightings of various seal species, including grey seals, along the eastern seaboard of the United States, as well as an increase in the number of seals needing rescue and rehabilitation. The cause is as yet unknown but some of the reasons being suggested include larger seal populations due to cleaner habitat and/or reduced hunting, increased commercial fishing in northern waters forcing seals further south to look for food, weather conditions and greater public awareness. Many of the seals requiring assistance were undernourished pups, while others were adults that had been injured, bitten by other seals or weakened by parasites or bacterial infections. In the winter of 2000 it was also reported by rescue centres in Ireland and Wales that they were rescuing record numbers of grey seal pups with conditions such as milky white eyes, mouth ulcers, swelling in the lower jaw and gums, crumbling jaws, brittle bones and flu-like symptoms. Organisations in both countries called on the authorities to investigate the causes of the increased strandings and mortality.
The grey seal is currently listed as a protected species under Annex II and Annex V of the European Community's Habitats Directive and several important sites for grey seals have been proposed in EC member countries as Special Areas of Conservation under the Directive. In August 1999 the Scottish Wildlife Trust purchased the 56-hectare uninhabited island of Linga Holm in the Scottish Orkney Islands, the world's third largest island-based grey seal breeding colony, as a sanctuary for grey seals. The Trust said that it would monitor the seals' progress, counter the threats that face them, including calls from fisheries interests for culls, and work towards greater legal protection for the island's grey seal population. The grey seal is also listed as an Appendix III species under the Bern Convention.
Baltic Sea: The Baltic Sea is thought to have contained about 100,000 grey seals at the start of the 20th century, but their numbers have been reduced drastically by hunting and pollution. Currently the population appears to be recovering in the northern part of the Baltic Sea and the Bay of Bothnia. However there are concerns for the viability of the meagre population in the southern Baltic Sea. The Baltic Sea grey seal population is listed as Endangered on the IUCN Red List, as an Appendix II species under the Bonn Convention and as an Appendix III species under the Bern Convention. The species is also protected through legislation and nature reserves by various countries within its range. The hunting of grey seals was banned throughout the Baltic Sea in 1988 by signatories to the Helsinki Convention. There has recently been mounting pressure however, particularly from Finland and Sweden, for this ban to be lifted in order to re-allow hunting. This pressure exists even though scientific research published in 1997 calculated that the level of hunting that the Baltic grey seal population could sustain was close to zero.
Halichoerus grypus - Image 2

Photo: Orkney Seal Rescue		 The Baltic Sea is one of the most polluted bodies of water in the world and it is thought that illness and lesions found in the grey seals there are connected with chemical pollutants. Particularly implicated are persistent contaminants such as PCBs and other organochlorines which bioconcentrate through the food chain and end up in very high concentrations in grey seal blubber. Individuals have suffered from reproductive failure since the 1950s and although measures have been taken to reduce this problem and the situation is much better today than it was twenty years ago, reproductive problems and other pollution-related illnesses are still affecting Baltic grey seals. Studies have shown that the frequency of severe intestinal ulcers has increased dramatically over the last ten years, even in very young seals.
Disturbance, entanglement in marine debris and illegal shooting of grey seals are all additional threats to the population. Concerns have been expressed about the disturbance to grey seals and possible spills that may occur as a result of the construction of new ports and oil and chemical terminals in the Gulf of Finland.
Problems exist due to the interactions of grey seals and Baltic Sea fisheries. A significant number of grey seals, particularly young seals, die through entanglement in fishing gear and the reported figures are almost certainly understated due to inconsistent reporting between countries. Grey seals are also blamed for damaging fishing gear and catch. In 1997, after pressure from fishing interests, the Swedish authorities shot 16 grey seals near fishing gear as part of a project to determine whether such killing would reduce the amount of damage caused. Concern has been expressed by conservation groups as to the necessity, scientific validity and humaneness of such "scientific" killing, and the development of alternative non-lethal deterrence methods is being actively promoted. The results of the Swedish trial indicated that the shooting had no effect on damages.
Despite the conclusions of the Swedish trial the government in Finland is now allowing the hunting of grey seals to take place, using the argument that such hunting aids the protection of fisheries. The government announced in 2000 that it was extending the grey seal hunting period, granting licences to shoot an extra 40 grey seals in the Gulf of Bothnia before the end of the current hunting season (bringing the total for the 1999-2000 hunting season to 100) and increasing the number of licences for the 2000-2001 hunting season to 120. In addition to the concerns being voiced about the hunting of grey seals in Finland, there are worries that the number of seals shot will be understated, some seals being wounded and killed but not counted in the official statistics. Fishermen and fish farmers in the Iland Islands are also granted permits to shoot grey seals, six such permits to shoot a total of 65 grey seals having been issued as of October 1999 to cover the period of autumn 1999 to the end of 2000.
Lifestyle
Grey seals are gregarious and gather together for breeding, moulting and hauling out. The breeding season varies between populations, taking place from mid-December to early February in Canada, late July to December in the U.K., February to April in the Baltic Sea, and peaking in October in Iceland and Norway. Breeding rookeries are formed on various types of habitat including rocky islands and coasts, caves, sandy islands and beaches, and in some areas of the Gulf of St. Lawrence on land-fast ice or ice floes. In the Baltic Sea pupping takes place mostly on pack ice in the middle of the sea although some seals also pup on land, noticeably in Estonia and on the Stockholm archipelago. This situation can vary if the winter has produced little ice in the Baltic Sea.
Females usually give birth about a day after coming ashore at the rookery. Their pup is born with a creamy-white woolly coat, which it will moult after 2-4 weeks for a shorter adult-like coat. The pup is nursed for about 17-18 days after it is born, gaining 1.2-2kg in weight per day. There appears to be a larger natural mortality of pups during this period in crowded rookeries or on wave-swept beaches. Towards the end of the period spent nursing her pup, the mother mates with one or more males and then after her pup is weaned she leaves it to fend for itself. The pup stays at the rookery until it has fully moulted, living off its blubber reserves, and eventually goes to sea to start feeding, usually about 1-4 weeks after it was weaned. Pups generally disperse in many different directions from the rookery and are known to wander widely, distances over 1,000km not uncommon.
Mating takes place on land, on ice or in the water. Generally the males enter the rookeries at about the time when the females start to pup and try to gain sole access to groups of females. The successful males are able to mate with 2-10 females. In locations however where the females are more spread out, usually on sand or ice, males are usually only able to mate with one female. There is recent evidence to show that the females have a greater degree of choice in their partners than the males. Neither lactating females nor dominant males feed during the breeding season, females usually for about 3 weeks and males sometimes for up to 6 weeks. Sub-dominant males may continue to feed since they remain at the periphery of the colonies. After mating, the seals disperse and wander widely in order to feed, usually in pelagic waters.
Most grey seals prefer exposed areas such as remote islands, rocky coasts and reefs on which to haul out. Grey seals can travel long distances between haulout sites while feeding. Many however feed more locally, foraging just offshore and adopting a regular pattern of travelling between these local sites and their favoured haulouts. Studies have shown that grey seals are very individualistic and that their preferred prey, haulout sites, and feeding locations and techniques differ greatly between individuals. They share much of their range, and some of their haulout sites, with the more coastal harbour seal. Members of the western Atlantic population moult from May-June, while the sexes in the British Isles population moult at different times, females from December-March and the males from March-May. Grey seals in the Baltic Sea moult on land or ice from April-June. Halichoerus grypus - Image 3

Photo: Tom Arnbom,
University of Stockholm
There is a great variety in grey seal coat coloration and shading. Males tend however to have a dark brown-grey coat, sometimes nearly black, with a few light patches, while females are generally light grey-tan coloured, lighter on the front, with dark spots and patches. Adult males, and some older adult females to a lesser extent, have a recognisable long "Roman" nose with wide nostrils, giving the species its name "horsehead" in Canada and its Latin name that translates as "hooked-nose pig of the sea". Grey seals are opportunistic feeders and eat an extremely wide variety of fish, crustaceans and cephalopods with regional and seasonal variations. Sand eels or sand lances are the preferred prey in many areas. Seabirds are also occasionally eaten. Grey seals are known to dive regularly to about 30-70m while feeding. Sharks are known to prey on grey seals in the western Atlantic, while killer whales have also been observed killing the occasional grey seal on both sides of the Atlantic.

Statistics
Adult males in the eastern Atlantic population generally measure 1.95-2.5m in length and weigh 170-310kg, adult females measuring 1.65-2.1m in length and weighing 103-180kg. The western Atlantic grey seals tend to be about 20% heavier. Pups are born measuring 90-105cm in length and weighing 10-18kg, generally at the lower end of this weight range in the Baltic Sea, and at the upper end in the western Atlantic population. The mortality rate for pups in their first year can be as high as 30-55%. Females reach sexual maturity at 3-5 years, males at 4-6 years, although males may not attain territorial status until 8-10 years of age. Grey seals have been known to dive to depths of 300m and stay underwater for up to 20 minutes. Females normally live up to 35 years of age, males up to 25 years, individuals in the western Atlantic population generally living longer. The maximum recorded ages are 46 years for a female, 29 years for a male.