RINGED SEAL } Pusa hispida
DESCRIPTION: Ringed seals, the most widespread Arctic marine mammal, have plump bodies decorated with prominent gray-white rings scattered across a light or dark gray coat. Adults vary widely in size but in Alaska, males average four feet in length and females average 3.6 feet. The average weight of adult Alaska ringed seals is 110 pounds, although pregnant females may exceed 220 pounds.
HABITAT: Ringed seals depend on sea ice to give birth, nurse pups, and haul out to complete the annual molt of their fur. Sea ice and snow also afford protection from polar bear and Arctic fox predators and provide insulation and shelter from extreme Arctic temperatures.
RANGE: Ringed seals have a wide circumpolar distribution in the seasonally and permanently ice-covered waters of the Northern Hemisphere, northward to the North Pole. In the North Pacific, they extend southward to the Bering Sea and southern Okhotsk Sea. In the North Atlantic, they extend southward to Newfoundland to the west and the Baltic Sea to the east.
MIGRATION: In winter to early summer, adult ringed seals occupy breeding areas primarily on stable landfast ice over the continental shelf along Arctic coasts, bays and inter-island channels. Younger seals usually occupy the outer, less-stable ice areas. As the sea ice retreats in late spring and summer, ringed seals in many regions move northward. During summer and fall when the sea-ice extent is at a minimum and has disappeared from many regions, ringed seals of all ages occur along the edge of the permanent pack ice, on near-shore ice remnants, or in open water.
BREEDING: Females give birth to a single pup in a snow lair on the landfast ice or pack ice during March and April and nurse their pups for five to seven weeks. Mating generally occurs in the water one month after females have given birth. Gestation lasts until the next spring, when another pup is born.
LIFE CYCLE: Female seals reach sexual maturity at four to eight years of age, while males do so at five to seven years. Average life expectancy is 15 to 20 years, though seals can live at least 43 years. Ringed seals’ delayed maturity, low reproductive rates, high adult survival and high longevity make them slow to recover from population declines.
FEEDING: Ringed seals primarily eat fishes of the cod family (especially Arctic and saffron cod), krill, shrimp and other small crustaceans. The Arctic cod is the dominant prey in most localities.
THREATS: The primary threat to the ringed seal is global warming, which melts the sea ice it depends on for giving birth, nursing pups, resting and molting, and which depletes its prey through ocean acidification. Global warming exacerbates other threats to the ringed seal, including oil and gas development, shipping activities, fishery bycatch mortality, oil spills, ocean noise pollution, hunting, ocean contamination and human disturbance.
POPULATION TREND: Ringed seals are the most abundant Arctic seal and are thought to number more than one million individuals. Population trends for ringed seals are difficult to detect because there are few repeated or reliable abundance estimates. However, population declines have occurred in populations for which trends have been analyzed. Ringed seals in the Canadian Arctic are suffering reproductive failures, higher pup mortality, and decreased body condition due to earlier snow melt and breakup of sea ice.