Distribution and Habitat
The ringed seal has a circumpolar distribution and is resident in North Pacific, North Atlantic and Arctic waters. There are five subspecies: the nominate subspecies hispida in the Arctic Ocean, Bering Sea and North Atlantic Ocean; botnica in the Baltic Sea including the Gulfs of Bothnia, Finland and Riga; ladogensis in Lake Ladoga, Russia; saimensis in Lake Saimaa, Finland and water bodies connected to it by passable rivers; and ochotensis in the Sea of Okhotsk and the northwestern Pacific Ocean.
Ringed seals use fast ice and sometimes dense pack ice for whelping, and numbers are strongly related to the relative permanence and density of ice in southern parts of their range. Pups are born in snow covered birth lairs, although ringed seals in the Okhotsk Sea regularly give birth on the exposed sea surface. Ringed seals have been seen within 2 km of the North Pole.
Adult ringed seals are 99 - 157 cm in length and weigh 45 - 107 kg. Females are slightly smaller than males. The Baltic and Ladoga Lake subspecies are somewhat larger than the other subspecies. Pups are 55-65 cm in length and weigh 4-5 kg at birth. Pups are born with a long, white (greyish in the Saimaa Lake subspecies) lanugo that is moulted after 4-6 weeks. Adult coat colour is variable among subspecies, with rings on the sides and back. The subspecies hispida is illustrated above. Sexual maturity is attained in 5-7 years, males generally mature somewhat later than females. Breeding takes place in mid to late May. Pregnancy rates exceeding 95% of mature females have been reported. Gestation lasts 10.5-11 months. All subspecies (except P.h. ochotensis) give birth in snow lairs over breathing holes in fast ice, for protection against cold temperatures and predators such as polar bears. Longevity is reported to be 46 years. Diet varies seasonally and among subspecies, and is predominantly small schooling fish and crustaceans.
The world population of ringed seals is estimated to be 6-7 million. The Lake Saimaa subspecies is listed on the IUCN Red List as Endangered. The Lake Ladoga and Baltic subspecies are listed as Vulnerable.
Threats to the Species
Ringed seals (P.h. hispida, and P.h. ochotensis) are hunted legally in the USA, Russia, Canada and Greenland. Maximum sustainable yield is estimated at approximately 7% of total population and the level of hunting being sustained up to 1999 is not believed to pose a threat. The Baltic subspecies was the focus of a hunt which was closed due to overexploitation in 1988, since which time hunting has been banned. Both lake-dwelling subspecies are affected by habitat destruction, disturbance and bycatch in fisheries. All subspecies are considered to be at risk from chemical pollutants, particularly the Baltic and freshwater subspecies.
Reijnders, P. et al. 1993. Seals, Fur Seals, Sea Lions, and Walrus. Status Survey and Conservation Action Plan. IUCN Seal Specialist Group. Gland, Switzerland. 87pp.
Reeves, R. R. 1998. Distribution, abundance and biology of ringed seals (Phoca hispida): an overview. Pages 9-45 in Heide-Jørgensen, M.P. and C. Lydersen (eds.). Ringed seals in the North Atlantic. NAMMCO Scientific Publications Volume 1. 273 pp.
Rice, D.W. 1998. Marine mammals of the world: systematics and distribution. The Society for Marine Mammalogy Special Publication Number 4. 231 pp.