Ringed Seal

Ringed seals are the smallest and most common Arctic seal. They get their name from the small, light-colored circles, or rings, that are scattered throughout the darker hair on their backs.

Ringed seals are circumpolar and are found in all seasonally ice-covered seas of the Northern Hemisphere and in certain freshwater lakes. Throughout their range, ringed seals have an affinity for ice-covered waters and are well-adapted to occupying heavily ice-covered areas throughout the fall, winter, and spring by using the stout claws on their foreflippers to maintain breathing holes in the ice. Ringed seals remain in contact with the ice most of the year and normally whelp and nurse pups on the ice in snow-covered lairs (snow caves) in late winter through early spring. The ice and snow caves provide some protection from predators, though polar bears spend much of their time on sea ice hunting ringed seals, which are their primary prey. Snow caves also protect ringed seal pups from extreme cold. Loss of sea ice and snow cover on the ice poses the main threat to this species.

Ringed seals, like all marine mammals, are protected under the Marine Mammal Protection Act. There are five currently recognized subspecies of the ringed seal: Arctic ringed seals in the Arctic Basin and adjacent seas, including the Bering and Labrador Seas; Okhotsk ringed seals in the Sea of Okhotsk; Baltic ringed seals in the Baltic Sea; Ladoga ringed seals in Lake Ladoga, Russia; and Saimaa ringed seals in Lake Saimaa, Finland. These subspecies are listed as endangered or threatened under the Endangered Species Act. Because of their listed status, these subspecies are also designated as depleted under the MMPA.

Ringed seals have a small head; a short cat-like snout; and a plump body. Their coat is dark with light-colored rings on their back and sides, and a light-colored belly. Pups are born with a white natal coat (lanugo) which is shed after about four to six weeks. Ringed seals have thick, strong claws on their small foreflippers that they use to maintain breathing holes through 6 feet or more of ice.

Ringed seals grow to an average length of 4 to 4.5 feet with weights ranging from 110 to 150 pounds. The average weight of a ringed seal pup at birth is about 10 pounds.

Ringed seals eat a wide variety of mostly small prey. They rarely prey on more than 10 to 15 species in any specific geographic location, and not more than two to four of these species are considered important prey. Despite regional and seasonal variations in the diet of ringed seals, fishes of the cod family tend to dominate the diet in many areas from late autumn through spring. Crustaceans appear to become more important in many areas during the open-water season and often dominate the diet of young seals. While foraging, ringed seals dive to depths of up to 150 feet or more.

Ringed seals can live in areas that are completely covered with ice. They use their sharp claws to make and maintain their own breathing holes through the ice, which may be 6 feet or more in thickness. In winter through early spring, they also carve out lairs in snowdrifts over their breathing holes. As the temperatures warm and the snow covering their lairs melts during spring, ringed seals transition from lair use to basking on the surface of the ice near breathing holes, lairs, or cracks in the ice as they undergo their annual molt. Ringed seals do not live in large groups and are usually found alone, but they may occur in large groups during the molting season, gathered around cracks or breathing holes in the ice.

Ringed seals are circumpolar and range throughout the Arctic Basin and southward into adjacent seas, including the Bering and Labrador Seas. They are also found in the Sea of Okhotsk and Sea of Japan in the western North Pacific and the Baltic Sea in the North Atlantic. Landlocked populations inhabit Lakes Ladoga (Russia) and Saimaa (Finland).

During winter and spring in the United States, ringed seals are found throughout the Beaufort and Chukchi Seas; they occur in the Bering Sea as far south as Bristol Bay in years of extensive ice coverage. Most ringed seals that winter in the Bering and Chukchi Seas are thought to migrate northward in spring with the receding ice edge and spend summer in the pack ice of the northern Chukchi and Beaufort Seas.

Sexual maturity in ringed seals varies with population status. It can be as early as 3 years for both sexes and as late as 7 years for males and 9 years for females. Ringed seals breed annually, with timing varying regionally. Mating takes place while mature females are still nursing their pups on the ice and is thought to occur under the ice near birth lairs.

In all subspecies except the Okhotsk, females give birth to a single pup hidden from view within a snow-covered birth lair. Ringed seals are unique in their use of these birth lairs. Although Okhotsk ringed seals have reportedly used them, this subspecies apparently depends primarily on the protective sheltering of ice hummocks (rounded hills of ice). Pups learn how to dive shortly after birth. They are nursed for as long as 2 months in stable ice that is fastened to the coastline and for as little as 3 to 6 weeks in moving ice. Pups are normally weaned before the break-up of spring ice.

Climate Change Effects on Sea Ice and Snow

Many aspects of the ringed seal’s life cycle depend directly on the species’ sea ice habitat. As such, the ongoing and anticipated reductions in the extent and timing of ice cover, especially on-ice snow cover, stemming from climate change (warming) poses a significant threat to this species.

Entanglement in Fishing Gear

Arctic ringed seals are seldom caught in fishing gear because their distribution does not coincide with intensive fisheries in most areas. Bycatch likely occurs on some level in the Sea of Okhotsk. Drowning in fishing gear is a significant source of mortality for Saimaa ringed seals (which occur in Lake Saimaa, Finland) and Ladoga ringed seals (which occur in Lake Ladoga, Russia).

Additional Factors of Potential Concern

The continuing decline in summer sea ice in recent years has renewed interest in using the Arctic Ocean as a potential waterway for coastal, regional, and trans-Arctic marine operations, which pose varying levels of threat to Arctic ringed seals depending on the type and intensity of the shipping activity and its degree of spatial and temporal overlap with the seals. Offshore oil and gas exploration and development could also impact ringed seals. The most significant risk that these activities pose is accidentally or illegally discharging oil or other toxic substances, which would have immediate and potentially long-term effects. Ringed seals could also be directly affected by noise and physical disturbance of habitat associated with such activities.