Ribbon Seal (Histriophoca fasciata)

	Ribbon Seal (Histriophoca fasciata) Photo: Captain Budd Christman, NOAA Corps

	Did You Know? · While on ice, ribbon seals will run across using alternating front legs and swinging their hindquarters rather than using caterpillar movement like most seals.

Status
Species of Concern - throughout its range
MMPA - Ribbon seals, like all marine mammals, are protected under the MMPA.

Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Phocidae
Genus: Histriophoca
Species: fasciata

Species Description
The ribbon seal is one of nine species of ice seals inhabiting the Arctic and is the only species in the genus Histriophoca.Adult ribbon seals measure, on average, about 5 ft (1.5 m) long and weigh about 175 lbs (80kg). Pups measure about 3 feet (1 m) at birth and weigh about 25 lbs (11 kg). Ribbon seals living in the southern part of the Okhotsk Sea tend to be bigger and heavier than those living elsewhere (Fedoseev 2002).

Ribbon seals consume about 20 lbs (9 kg) of food each day, mainly feeding on pelagic fish and invertebrates, such as shrimp, crabs, squid, octopus, cod, sculpin, pollack, and capelin. Juveniles feed mostly on krill and shrimp.

Ribbon Seal pup with white "lanugo" coat
(Histriophoca fasciata)
Photo: Dave Withrow, NOAA
NOAA Alaska Fisheries Science Center Polar Ecosystems Program research cruise

Pups are born with a wooly white lanugo coat, which they shed after the period of lactation, which lasts for 3-5 weeks. After one year, juveniles begin to develop a dark body and light bands encircling the neck, each front flipper, and hips. These light bands become brighter after another year. Males generally have darker bodies than females.

Ribbon seals alternate their foreflippers and swing their hindquarters to run across ice, rather than using the caterpillar-like movement typically used by most seals. Ribbon seals are also physiologically and anatomically adapted to make deeper dives (up to about 1950 ft (600 m)) and swim faster than other seals (Fedoseev 2002). They have an air sac that may function as a buoyancy device, for air storage during diving, or for "phonation" (Kelly 1988).

Ribbon seals become sexually mature after 3-5 years. Adult ribbon seals produce one offspring per year, and gestation lasts 11 months. They breed in May and give birth the following year between late March and April. Molting occurs annually between March and July; juveniles molt earlier and adults molt after giving birth. On average, ribbon seals live for about 20 years, but can reach up to about 30 years.

unmanned aircraft captured image of a ribbon seal on sea ice

Video: Unmanned Aircraft Sees Ribbon Seal on Ice [mov]
NOAA Alaska Fisheries Science Center Polar Ecosystems Program research cruise

Habitat
Ribbon seals inhabit the North Pacific Ocean, specifically the Bering and Okhotsk Seas, and parts of the Arctic Ocean, including the Chukchi, eastern Siberian, and western Beaufort Seas. They are strongly associated with sea ice for mating, whelping pups and molting from mid-March through June. Most of the rest of the year is spent at sea; they are rarely seen on land. They seem to prefer moderately thick, stable, new, clean, white ice floes with even surfaces. They also avoid areas of thick ice. When the ice recedes and the breeding and molting seasons come to an end, ribbon seals move northward until the ice gets too thick and then remain in the water for the rest of the year. Little is known about the distribution of ribbon seals while they are "pelagic".

Ribbon Seal Range Map
(click for larger view PDF)

Distribution
Ribbon seals inhabit the North Pacific Ocean, specifically the Bering and Okhotsk Seas, and parts of the Arctic Ocean, including the Chukchi, eastern Siberian, and western Beaufort Seas. They are strongly associated with sea ice for mating, whelping pups and molting from mid-March through June. Most of the rest of the year is spent at sea; they are rarely seen on land. They seem to prefer moderately thick, stable, new, clean, white ice floes with even surfaces. They also avoid areas of thick ice. When the ice recedes and the breeding and molting seasons come to an end, ribbon seals move northward until the ice gets too thick and then remain in the water for the rest of the year. Little is known about the distribution of ribbon seals while they are pelagic.

Population Trends
In the 1960s, the population of ribbon seals in the Bering Sea was reduced from about 120,000 to 70,000. The population size increased back to about 130,000 in 1987 after quotas were set to limit harvest to about a fourth of the number of seals hunted previously.

In the latest stock assessment (2007), NMFS estimated a global population size of 240,000 ribbon seals, 90,000-100,000 of which inhabit the Bering Sea. In the Okhotsk Sea, the average number of ribbon seals was 370,000 between 1968 and 1988. The current population trend is unknown, but recent estimates suggest that no catastrophic declines have occurred in recent decades.

Threats
Ribbon seals have been hunted for generations and are still hunted today by Siberia and Alaska natives for subsistence, but the number of seals harvestedhas always been relatively small (less than 100 in Alaska).

In the early 1950s, the USSR began commercially harvesting ribbon seals in the Sea of Okhotsk ; the fishery quickly intensified in the 1960s,with an average of about 13,000 to 20,000 seals harvested per year. Ribbon seals were also hunted in the Bering Sea beginning in 1961, with an annual harvest of nearly 10,000 individuals. As the ribbon seal population declined, annual harvest also fell, dropping to 3,500 in the Sea of Okhotsk and 3,000 in the Bering Sea in the 1980s (Popov, 1982). Harvest continued to fluctuate in relation to ribbon seals abundance and political and economic unrest. Although the Russian governmentquotas recently put in place would allow large annual harvests (18,000), the annual harvest remains relatively low today.

Other human impacts to ribbon seals include growing oil and gas development in the Okhotsk and Bering Seas, oil spills, and incidental take in commercial fisheries. In addition, global warming may affect the frequency of years with extensive ice, the quality of the ice, and the duration its persistence such that the amount of available sea ice habitat for ribbon seals within their historic range is reduced.

NOAA Researchers Weigh an Adult Female Ribbon Seal

Video: NOAA Researchers Weigh a Ribbon Seal [mov]
NOAA Alaska Fisheries Science Center Polar Ecosystems Program research cruise

Conservation Efforts
The National Marine Mammal Laboratory is studying and monitoring ribbon seals to increase our knowledge of the species' abundance, distribution, behavior, population structure, and diet. Currently, the ribbon seal is a species of concern. Like all marine mammals, the ribbon seal is protected under the Marine Mammal Protection Act of 1972.

Regulatory Overview
On December 20, 2007, NMFS received a petition from the Center for Biological Diversity to list the ribbon seal as threatened or endangered under the ESA and to designate critical habitat. NMFS published a finding on March 28, 2008, that the petitioned action may be warranted and initiated a status review of the species. NMFS completed the status review report on December 30, 2008, and determined that the ribbon seal does not currently warrant listing under the ESA.

Key Documents
(All documents are in PDF format.)

Title	Federal Register	Date
Species of Concern Fact Sheet: Detailed	n/a	06/10/2009
Fact Sheet Highlights	n/a	12/30/2008
NOAA Determines Ribbon Seals Should Not be Listed as Endangered	73 FR 79822	12/30/2008
Status Review Report	n/a	12/2008
90-Day Finding on a Petition to List the Ribbon Seal Under the Endangered Species Act; Initiation of Status Review for 3 Other Seals	73 FR 16617	03/28/2008
Stock Assessment Reports	n/a	various

More Information

References

Fedoseev, G. (2002). Ribbon seal Histriophoca fasciata. Pp. 1027-1030 in W. F. Perrin, B. Wursig, and J. G. M. Thiewissen, eds. Encyclopedia of marine mammals. Academic Press.
Kelly, B. P. 1988. Ribbon seal. Pages 95-106 inJ. W. Lentfer, editor. Selected Marine Mammals of Alaska : Species Accounts with Research and Management Recommendations. Marine Mammal Commission, Washington, D.C.
Popov, L. A. 1982. Status of the Main Ice-Living Seals Inhabiting Inland Waters and Coastal Marine Areas of the USSR. Pages 361-381 inMammals in the seas. Vol IV. Small Cetaceans, Seals, Sirenians and Otters. FAO Fisherhies Series.