Ribbon seal - Photo: NOAA Fisheries
Ribbon seal - Photo: NOAA Fisheries
About the Species
Ribbon seal - Photo: NOAA Fisheries
Ribbon seal - Photo: NOAA Fisheries
Ribbon seals are among the most striking and easily recognizable seals in the world. The ribbon seal gets its name from the distinctive adult coat pattern of light-colored bands or “ribbons” on a dark background.
Ribbon seals inhabit the North Pacific Ocean and adjacent southern parts of the Arctic Ocean. In U.S. waters, they are found off the coast of Alaska in the Bering Sea and in the Chukchi and western Beaufort Seas. Ribbon seals are considered relatively solitary, spending most of their time in the open ocean and forming loose aggregations on pack ice during spring to give birth, nurse pups, and molt. As such, they are sensitive to changes in the environment that affect the timing and extent of sea ice formation and breakup.
Ribbon seals, like all marine mammals, are protected under the Marine Mammal Protection Act.
Population Status
Although it is difficult to accurately estimate the total abundance of ribbon seals, scientists have concluded that the range-wide population likely consists of at least 200,000 to 300,000 seals. The current population trend cannot be determined, but strong upward or downward trends in the recent past seem unlikely based on the available data. Only the Alaska stock of ribbon seals is recognized in U.S. waters.
Historically, subsistence harvest of ribbon seals has been low. While commercial harvest of marine mammals is not allowed in the United States, such harvests are permitted by the Russian Federation. Commercial harvests by Russian sealers have at times been high enough to cause significant reductions in abundance; however, since 1994 harvest levels have remained low.
Appearance
The ribbon seal gets its name from the distinctive pattern exhibited by mature individuals, which consists of light-colored ribbons that encircle the neck, each foreflipper, and hips. Adult males are the most striking, having a dark brown to black coat with white ribbons, while adult females range from silvery-gray to dark brown with paler ribbons. Juvenile ribbon seals typically have indistinct ribbons that gradually develop over 3 years with each successive annual molt. Ribbon seal pups are born with a thick, wooly white coat (lanugo) that is molted after 3 to 5 weeks.
Ribbon seals are medium-sized when compared with the other three species of ice-associated seals in the North Pacific, being larger than ringed seals, smaller than bearded seals, and similar in size to spotted seals. At birth, ribbon seal pups are approximately 34 inches long and weigh about 21 pounds. Adults are about 5 to 6 feet long and weigh about 200 to 330 pounds.
Behavior and Diet
Ribbon seals are considered relatively solitary, spending most of their time in the open ocean and forming loose aggregations in pack ice during spring to give birth, nurse pups, and molt. Unlike most other northern seals, they are relatively unwary of their surroundings while hauled out, which suggests they have not been exposed to the same level of predation (e.g, from polar bears and foxes).
Ribbon seals move across the ice in a way that is distinct from the caterpillar-like movement of other ice seals. They alternate foreflipper strokes to pull themselves forward while moving their head and hips in a side-to-side motion.
Ribbon seals are known to eat a variety of fishes, cephalopods, and crustaceans; however, information about their feeding habits is limited and mostly restricted to the spring when they typically feed less.
Where They Live
Ribbon seals inhabit the North Pacific Ocean and adjacent southern parts of the Arctic Ocean, where they occur most commonly in the Sea of Okhotsk and Bering Sea. In U.S. waters off the coast of Alaska, they are found in the Bering Sea and in the Chukchi and western Beaufort Seas. Ribbon seal breeding occurs in both the Bering Sea and Sea of Okhotsk.
Although ribbon seals are strongly associated with sea ice during the whelping (or birthing), breeding, and molting periods, they do not remain on sea ice after they finish molting. During summer, ice melts completely in the Sea of Okhotsk, and by the time the Bering Sea ice recedes north through the Bering Strait, there are usually only a small number of ribbon seals hauled out on the ice. Significant numbers of ribbon seals are only seen again when the sea ice reforms in winter.
Individual ribbon seals are occasionally sighted along the coasts of Asia and North America, which are not considered part of their normal range, or in unusual habitats within their range. For example, a young adult ribbon seal was observed on several occasions hauled out on docks in the inland waters of Washington state.
World map providing approximate representation of the ribbon seal's range.
Lifespan & Reproduction
The rates of survival and reproduction are not well known, but the normal lifespan of a ribbon seal is probably 20 years, with a maximum of perhaps 30 years. Ribbon seals become sexually mature at 1 to 5 years of age, most likely depending on environmental conditions.
Ribbon seal mothers give birth to a single pup far offshore in seasonal pack ice over a period of about 5 to 6 weeks during April to early May. Most pups are weaned by mid-May, which occurs when the mother abandons the pup. The mother typically breeds again shortly after weaning.
Threats
Climate Change Effects on Sea Ice
Ribbon seals rely on the availability of suitable sea ice as a haul-out platform for giving birth, nursing pups, and molting. As such, ribbon seals are sensitive to changes in the environment that affect timing and extent of sea ice formation and breakup. The 2013 status review of the ribbon seal under the ESA concluded that it is likely that ongoing and projected changes in sea ice (and possible changes to their prey base related to changes in ocean conditions) will result in a gradual decline in seal abundance.
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 ribbon 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 ribbon 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. Ribbon seals could also be directly affected by noise and physical disturbance of habitat associated with such activities.
While commercial harvest of marine mammals is not allowed in the United States, such harvests are permitted by the Russian government. Commercial harvests by Russian sealers have at times been high enough to cause significant reductions in abundance. Although recent quotas put in place by the Russian government would allow large annual harvests, harvest levels have remained low.
Scientific Classification
| Animalia |
Chordata |
Mammalia |
Carnivora |
Phocidae |
Histriophoca |
fasciata |
Last updated by NOAA Fisheries on 10/30/2023
