Harbour seal (Phoca vitulina) COSEWIC assessment and status report: chapter 2

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Executive Summary

Species information

The harbour seal (Phoca vitulina) is a small pinniped species with a variable pelage colouration of mottled brown, black and yellowish-white. In eastern Canada, few individuals exceed 154 cm and 100 kg, and 30 years of age. The subspecies occurring on Canada’s west coast is P. v. richardsi. Harbour seals in eastern Canada comprise two designatable units (DUs) that are different subspecies. One DU, P. v. mellonae, consists of the freshwater seals of the Lacs des Loups Marins area of Québec’s Ungava peninsula, and is endemic to Québec and Canada. The second unit, P. v. concolor, consists of the harbour seals found on the Canadian Atlantic and Arctic coasts and extends into Greenland, St. Pierre and Miquelon, and the United States.

Distribution

Understanding of the current distribution of harbour seals in many areas of eastern Canada is based on anecdotal sightings rather than directed surveys. Harbour seals are still found in a number of locations in the eastern Canadian Arctic including in some rivers. In the past, harbour seals occasionally ascended the St. Lawrence River to the Great Lakes. Harbour seals are found in numerous locations along the St. Lawrence River and Estuary; around the Gulf of St. Lawrence; along the southern shore of Nova Scotia, including Sable Island; in the Bay of Fundy; and in pockets along the coasts of Newfoundland and Labrador. Changes in this distribution over time are unclear.

The inland Québecpopulation has a much more limited distribution. The Cree and Inuit people of Whapmagoostui and Juujjuarapik (Great Whale, Quebec) consider the current range of P. v. mellonae to be Lacs des Loups Marins, Petit Lac des Loups Marins, and Lac Bourdel, with some reports of animals having once been in Lac à l'Eau Claire. Unlike harbour seals that move in and out of freshwater areas in other parts of the species’ circumboreal northern hemisphere range, the balance of evidence indicates long-term, year-round residency in the Lacs des Loups Marins area.

Habitat

P. v. concolorinhabits nearshore waters on Canada’s Arctic and Atlantic coasts and uses both aquatic and terrestrial habitat. They haul out on rocky or sandy substrates, often on isolated rocks and islets. Harbour seals lack elongated front claws and cannot excavate holes in the ice. They therefore rely on areas of permanent open water or spend the winter at the edge of the fast ice. Climate change may open new habitat for harbour seals in the Arctic. P. v. mellonae inhabit a small number of freshwater lakes in Quebec. All harbour seal habitat in Canada, whether aquatic or terrestrial, is under the control of provincial, territorial or federal governments.

Biology

The timing of pupping in P. v. concolor is variable and occurs later at higher latitudes. The estimated mean pupping date of P. v. mellonae is substantially earlier than for other harbour seal populations at similar latitudes, suggesting that P. v. mellonae may be reproductively isolated from P. v. concolor. Published stomach content and scat analyses for northwest Atlantic harbour seals indicate a broad diet, though little has been documented regarding the diet of harbour seals in the Arctic. Stable isotopes (carbon and nitrogen) and fatty acid analyses indicate that the diet of Lacs des Loups Marins seals is of freshwater origin. Harbour seals are often sedentary, exhibiting considerable fidelity to one or a few haulout sites, though they have also been recorded to move great distances. Tracking of P. v. mellonae showed that seals preferred small areas along the lakes’ shoreline and remained in the Lacs des Loups Marins area.

Population sizes and trends

There are no range-wide estimates of the abundance of P. v. concolor or P. v. mellonae in Canada. Only a few portions of the harbour seal’s eastern Canadian range have been recently surveyed, with varying methods and degrees of intensity. Summing the population estimates of the most recent studies of P. v. concolor’s Canadian range yields at least 10,000 animals, which is likely negatively biased. There are no clear trends in abundance. Estimates of the size of the P. v. mellonae population are imprecise, ranging from 100-600 animals. It is clearly a small population, and evidence indicates that it has declined over time.

Limiting factors and threats

Some opportunistic hunting of harbour seals still occurs. It is unknown if this mortality is significant. Harbour seals are also known to be killed incidentally in fishing gear, are easily disturbed by human activity, and may be threatened by environmental contaminants and some diseases. Competition with grey seals and predation by sharks are likely limiting factors on Sable Island. At present, the only known cause of human-induced mortality in P. v. mellonae is occasional hunting by Aboriginal people. Hydroelectric development in northern Québec would likely adversely affect this subspecies.

Special significance of the species

P. v. mellonaeis the world’s only known population of harbour seals that is restricted to freshwater environments. It is the object of reverence by the Cree and Inuit of northern Québec.

Existing protection or other status designations

P. v. mellonaewas listed as Special Concern by COSEWIC in April 1996, as “data deficient” by the IUCN, and as “susceptible to designation as threatened or vulnerable” by the government of Québec. It is ranked N2S1 (N2 “imperiled” in Canada and S1 “critically imperiled” in Québec) by NatureServe. None of the habitat of this population is protected. P. v. concolor was listed as Indeterminate (data deficient) by COSEWIC in April 1999, and as “not ranked” by NatureServe. The management of marine mammals in Canada is regulated by the Marine Mammal Regulations under the Fisheries Act. Current regulations do not allow harbour seal hunting in Atlantic Canada. Some haulout sites are protected from development by both provincial and federal protected areas.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2007)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)^Footnotea

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)^Footnoteb

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)^Footnotec

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.