In the Bering Sea and Sea of Okhotsk, adult female Spotted Seals usually weigh 65-115 kg and are 151-169 cm long, while adult males weigh 85-110 kg and are 161-176 cm long (Boveng et al. 2009). Maximum reported length was 182 cm for females and 185 cm for males (Tikhomirov 1968).

In spring, Spotted Seals give birth to a single pup, typically on the surface of sea ice but in some places on shore, particularly in the Bohai Sea, Peter the Great Bay, the South Kuril Islands, the second Kuril Strait, Utashud Island, and the east coast of Kamchatka (Trukhin 2005). Pups are born in a white lanugo coat that is shed at or before weaning, which occurs about four weeks after birth. At birth pups are 75-92 cm long and weigh 7-12 kg, and they grow to 30 kg or more by weaning (Boveng et al. 2009). Mating occurs after pups are weaned. Spotted Seals are annually monogamous and males defend lactating females on ice floes. Groups composed of a female with her pup and a male, called triads, are common during the breeding season (Quakenbush 1988).

In late-spring and summer many Spotted Seals leave the sea ice and haul out on land to rest when they are not foraging. On some haul-out sites in Kamchatka the number of animals on shore may exceed 10,000 individuals (V. Burkanov pers. comm.). As sea ice forms in October-November Spotted Seals again use the ice as their primary feeding and resting habitat (Burkanov 1990; Lowry et al. 1998, 2000). They are generalist feeders that take primarily a variety of fish species (Walleye Pollock, Arctic and Saffron Cod, Rockfish, Herring, Sand Lance, Smelt, Capelin, Eelpout, Salmon, Flatfishes), cephalopods (Squid and Octopus) and crustaceans (Shrimp and Crab) (Burkanov 1990, Quakenbush et al. 2009).

Reported predators include Pacific Sleeper Sharks, Killer Whales, Golden Eagles, Steller’s Sea Eagles, Ravens, Gulls, Polar and Brown Bears, Wolves, Arctic Foxes, Walruses and Steller Sea Lions (Quakenbush 1988).

Spotted Seals breed in the Bering Sea, the Sea of Okhotsk, the Sea of Japan, the Yellow Sea, and the Bohia Sea. They are also found outside the breeding season in the Chukchi and Beaufort seas, ranging north into the Arctic Ocean to about the edge of the continental shelf, west to about 170°E longitude, and east to the Mackenzie River Delta in Canada (Shaughnessey and Fay 1977, Quakenbush 1988). They inhabit the southern edge of the pack ice from winter to early summer. In late summer and fall, Spotted Seals move into coastal areas, including river mouths. They rarely occur in water depths greater than 200 m (Lowry et al. 2000). They breed mostly on sea ice and haul-out on sea ice when it is available, but they also haul out on beaches and sandbars (Burns 1970; Lowry et al. 1998, 2000). There are several sites along the Asian coast where Spotted Seals breed on small remote islands (e.g., in Peter the Great Gulf, the Kuril Islands, and small islands along east coast of Kamchatka; Burkanov 1988, 1990; Trukhin and Katin 2001; Kostenko et al. 2004; Vertyankin and Nikulin 2004).

In the United States the Spotted Seal is generally protected from all but subsistence hunting by Alaska Natives under the Marine Mammal Protection Act of 1972, which also generally prohibits import and export of parts or products from all marine mammals.

Commercial harvesting of Spotted Seals from vessels of the Russian Federation ended in 1994. Small scale commercial and subsistence harvests from small boats and land occurs along the Russian Far East coast, but the size of the harvest is relatively small (V. Burkanov pers. comm.).

Spotted Seals are listed in the Second Category (II) of the State Key Protected Wildlife List in China, listed as Vulnerable in the China Red Data Book of Endangered Animals, and designated a vulnerable species under the Wildlife Conservation Act of China (Wang 1998). However, as of 2004, no “conservation action, public awareness or education programmes have been carried out for the species in this region” (Won and Yoo 2004).

In 2000, Spotted Seals were afforded protected status under the Wildlife Conservation Act of South Korea. Despite this protection, the Liaodong Bay population, shared between China and Korea, has continued to decline (Han et al. 2010).