Mammal Species of the World
- Original description: Zimmermann, E.A.W., 1783. Geographische Geschichte des Menschen, und der allgemein verbreiteten vierfüssigen Thiere, nebst einer hieher gehörigen zoologischen Weltcharte. Dritter Band. Weygandschen Buchhandlung, Leipzig, (3rd volume) p. 277.
Ribbon seals are found in coastal areas of the north Pacific Ocean and in the seas bordering Alaska and Russia. The largest populations are in the Bering or Okhotsk seas.
Biogeographic Regions: arctic ocean (Native ); pacific ocean (Native )
- Burns, J. 1994. "Alaska Department of Fish and Game," (On-line). Accessed November 22, 1999 at http://www.state.ak.us/local/akpages/FISH.GAME/notebook/notehome.htm.
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Mainly pack ice from Hokkaido and the Sea of Okhotsk to northern Alaska and the Aleutian Islands; from late winter to early summer concentrated in ice-covered parts of the Chukchi, Bering, and Okhotsk seas and adjacent straits and bays (Nowak 1991). Most common in the Bering and Okhotsk seas; apparently relatively few summer in the Chukchi Sea (Reeves et al. 1992). Okhotsk Sea population may move into the Bering Sea for the summer.
The common name "ribbon seals" reflects the markings of their coat. The adult coat of a ribbon seal is most easily described as a dark background with four light colored stripes running in a circle around the animal. One stripe encircles the neck, another encircles the mid-posterior portion of the seal's body, and the other two stripes start ventrally and encircle the fore flippers on either side. Although this is the general pattern for all ribbon seals, there can be great individual variability as to the shade and precise location of the stripes. Males tend to be darker than females. Newborn and juvenile ribbon seals do not have this striped pattern; as newborns are completely white, while juvenile seals are dark anteriorally and dorsally, and grayish posteriorly and ventrally. Other ribbon seal traits include large eyes and small teeth. An adult will grow to about 1.6 m and weigh 70 kg, and has a lifespan of about 20 years.
Range mass: 70 to 80 kg.
Range length: 1.6 (high) m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
Length: 150 cm
Weight: 90000 grams
Size in North America
Range: 1.6-1.7 m
Range: 70-80 kg
Differs from other northern phocids by the unique color pattern and in having a relatively longer and more flexible neck, a shorter rostrum, and more widely spaced teeth (Nowak 1991).
Habitat and Ecology
Ribbon seals are solitary for much of their lives. Pups are born on ice floes from early April to early May. Clean, white, broken pack ice is preferred over solid ice sheets and ice with sediment or algae. Ribbon seals maintain access holes in ice up to approximately 15 cm thick, and can often be seen in the middle of large floes. Ribbon seals are able to move rapidly on ice, using slashing side-to-side motions. They also extend their necks to peer at sources of disturbance, but are fairly approachable by boat. They are rarely encountered, because of the remote and inhospitable nature of their habitat.
Diet varies by area and age of the seal. Ribbon seals in the Okhotsk and Bering seas are known to take 35 different species of fish and invertebrates (Frost and Lowry 1980, Bukhtiyarov 1986). Young ribbon seals feed on euphausiids after weaning and until about age one when they switch to feed predominantly on shrimp for a year. As two-year-olds they take up the adult diet, which includes a variety of fishes, squids, and octopuses. Bukhtiyarov (1986) has determined that diet biomass of ribbon seals in the Sea of Okhotsk contains 69% of pollock, while in the Bering Sea 67% was squid and octopuses.
Females are mature when they are 2-4 years old and males when they are 3-5 years (Burns 1981). The annual pregnancy rate of adult females is 85%. Gestation lasts 9 months after 2-2.5 months of delayed implantation. Ribbon seals may live up to 26-27 yrs. First year mortality is 44% and the annual mortality rate for older age classes averages 11%.
Ribbon seals are restricted to the cold waters of the northern Pacific. In winter and spring they forage and raise offspring on coastal ice flows, the summer months are spent in the open ocean.
Habitat Regions: temperate ; polar ; saltwater or marine
Terrestrial Biomes: icecap
Aquatic Biomes: pelagic ; coastal
- Meston, D. 1997. "Seal Conservation Society" (On-line). Accessed November 22, 1999 at http://www.greenchannel.com/tec/main.htm.
Habitat Type: Marine
Comments: Associated with sea ice during late winter, spring, and early summer; prefers to haul out on moderately thick, clean ice, generally on ice floes well out to sea (Nowak 1991). Rarely hauls out on shore-fast ice and almost never on land. Gives birth on moderately thick, clean sea ice (Nowak 1991), generally far offshore (except when ice edge is near St. Matthew and St. Lawrence islands).
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.
At least some migrate northward and southward with the receding and advancing ice edge.
Ribbon seals eat primarily fish, taking fish species depending on their relative abundance in the area. Ribbon seals also eat squid, shrimp, and crabs. Juvenile seals have been reported to eat a lare proportion of crustaceans.
Animal Foods: fish; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Comments: Feeds opportunistically on crustaceans, fishes (important species include walleye pollock and arctic cod), and cephalopods. Food intake is reduced during spring molt.
Usually solitary, though scattered individuals may assemble on favorable ice flows (Nowak 1991). Mortality during the first four years of life is nearly 58% (Reeves et al. 1992).
Life History and Behavior
Communication and Perception
Communication Channels: acoustic
Perception Channels: visual ; acoustic
Ribbon seals live about 20 years in the wild.
Status: wild: 20 (high) years.
Lifespan, longevity, and ageing
Males have a well-developed air sac extending from the posterior trachea. The function is unknown but it is likely to be used in underwater vocalizations that may be to attract females and compete for mates.
Mating System: polygynous
Adult females become pregnant once a year, giving birth sometime in April or May. Typically ribbon seals give birth to one pup with the birthing occurring on ice flows. Nursing lasts up to a month, a time during which the weight of the pup will double. As soon as the pups are weaned, adults will mate again. Ribbon seals employ a delayed implantation of two or three months, this is most likely to assure the presence of ice at the time of birth. After weaning, pups spend a lot of time practicing diving and learning how to move on the ice.
Average number of offspring: 1.
Average gestation period: 11 months.
Average weaning age: 1 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous
- Burns, J. 1994. "Alaska Department of Fish and Game," (On-line). Accessed November 22, 1999 at http://www.state.ak.us/local/akpages/FISH.GAME/notebook/notehome.htm.
Apparently polygynous mating system. Mating occurs about the same time as weaning. Gestation, including a period of delayed implantation, lasts about 11 months. Births of single pups occur in April and early May (mainly early to mid-April). Young are weaned in 3-4 weeks, remain mostly on the ice for a few more weeks. Females becomes sexually mature at 2-4 years; many do not produce a pup until 4-5 years old; thereafter, almost all adult females give birth annually. Males are sexually mature at 3-5 years. Most probably do not live beyond 20 years.
Molecular Biology and Genetics
Barcode data: Phoca fasciata
There are 3 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Phoca fasciata
Public Records: 3
Specimens with Barcodes: 3
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
IUCN Evaluation of the Ribbon Seal, Histriophoca fasciata
Prepared by Pinniped Specialist Group
A. Population reduction Declines measured over the longer of 10 years or 3 generations
A1 CR > 90%; EN > 70%; VU > 50%
Al. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are clearly reversible AND understood AND have ceased, based on and specifying any of the following:
(a) direct observation
(b) an index of abundance appropriate to the taxon
(c) a decline in area of occupancy (AOO), extent of occurrence (EOO) and/or habitat quality
(d) actual or potential levels of exploitation
(e) effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.
The generation time of Ribbon Seals is probably about 10 years. The most recent population abundance estimate, based on aerial surveys conducted in 1979, was between 450,000 and 500,000 with an increasing trend. No reliable surveys have been conducted since 1979 and current abundance and trend are unknown. A decline in Ribbon Seals in the Bering Sea was observed in mid-late 1960s due to overharvesting. After reduction of harvest effort the population recovered rapidly. Large scale commercial harvests of ribbon seals in the Russian Far East ceased in 1994.
A2, A3 & A4 CR > 80%; EN > 50%; VU > 30%
A2. Population reduction observed, estimated, inferred, or suspected in the past where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
A population reduction of Ribbon Seals has not been observed, estimated, inferred, or suspected in the past 30 years.
A3. Population reduction projected or suspected to be met in the future (up to a maximum of 100 years) based on (b) to (e) under A1.
A population reduction of Ribbon Seal is suspected in the future due to global warming and rapid reduction of sea ice habitat essential for pupping and moulting. If global warming continues it is likely that the population of ribbon seals will decline by at least 30% within next 30 years which qualifies the species for listing as vulnerable under criterion A3c.
A4. An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years) where the time period must include both the past and the future, and where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under Al.
The cause of the Ribbon Seal decline in the 1960s-1970s was understood and reversible. No other population reduction of ribbon seal has been observed, estimated, inferred, or suspected in the past.
B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence (EOO): CR < 100 kmÂ²; EN < 5,000 kmÂ²; VU < 20,000 kmÂ²
The EOO of Ribbon Seal is > 20,000 kmÂ².
B2. Area of occupancy (AOO): CR < 10 kmÂ²; EN < 500 kmÂ²; VU < 2,000 kmÂ²
The AOO of Ribbon Seal is > 2,000 kmÂ².
AND at least 2 of the following:
(a) Severely fragmented, OR number of locations: CR = 1; EN < 5; VU < 10
(b) Continuing decline in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals.
(c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (iv) number of mature individuals.
C. Small population size and decline
Number of mature individuals: CR < 250; EN < 2,500; VU < 10,000
The number of mature ribbon seals is > 10,000.
AND either C1 or C2:
C1. An estimated continuing decline of at least: CR = 25% in 3 years or 1 generation; EN = 20% in 5 years or 2 generations; VU = 10% in 10 years or 3 generations (up to a max. of 100 years in future)
C2. A continuing decline AND (a) and/or (b):
(a i) Number of mature individuals in each subpopulation: CR < 50; EN < 250; VU < 1,000
(a ii) % individuals in one subpopulation: CR = 90â100%; EN = 95â100%; VU = 100%
(b) Extreme fluctuations in the number of mature individuals.
D. Very small or restricted population
Number of mature individuals: CR < 50; EN < 250; VU < 1,000 AND/OR restricted area of occupancy typically: AOO < 20 kmÂ² or number of locations < 5
The number of mature Ribbon Seals is > 1,000. AOO is > 20 kmÂ² and the number of locations is > 5.
E. Quantitative analysis
Indicating the probability of extinction in the wild to be: CR > 50% in 10 years or 3 generations (100 years max.); EN > 20% in 20 years or 5 generations (100 years max.); VU > 10% in 100 years
There has been no quantitative analysis conducted on probability of extinction of Ribbon Seals.
Listing recommendation â Ribbon Seals have an unknown mortality in salmon nets and bottom-set gill nets. This species is likely to be seriously, negatively impacted by reductions in the extent and seasonal coverage of sea ice throughout their range. However, it is not possible to evaluate the current situation for this species as the most recent estimates are almost two decades old. This species must be considered Data Deficient at this time.
It is thought that the number of ribbon seals in the wild is increasing due to decreased hunting pressure. However, no surveys of ribbon seal populations have been completed since the mid 1970's. The largest human-created problem facing ribbon seals is the occasional accidental netting of individuals in Pacific fishing areas. (Burns, 1994; Meston, 1997; "World Conservation Monitoring Centre" website, 1999)
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: data deficient
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
The Bering Sea population appears to have declined shortly after the beginning of commercial hunting in 1961. The average age of harvested animals declined from 9.8 years in 1961, to 6.9 in 1962, and 4.9 in 1963. During the same period, the number of ribbon seals killed per day dropped regardless of hunting conditions (Heptner 1976). After the harvest was limited, abundance of the species quickly recovered.
Interactions between ribbon seals and fisheries are not well documented. There were no mortalities recorded in required logbooks or by voluntary reports from 1990 to 1995 in fisheries monitored by the United States. Estimated mortality from 1999 to 2003 was 1 ribbon seal in the Bering Sea pollock trawl fishery, and 1 observed and 3 estimated mortalities in the Bering Sea/Aleutian Islands Pacific cod longline (Anglis and Outlaw, 2005). During seven years (1993-1999) of monitoring the offshore salmon gill net fishery in Russian Far East, accidental mortality of ribbon seal was estimated to be 1,079 individuals (154 per year), mostly juveniles (Burkanov and Nikulin 2001). Some mature animals die in a bottom gill net halibut fishery in the Sea of Okhotsk, but information is very limited.
Reduction in late winter and spring sea ice cover in the Sea of Okhotsk, or the central and southern Bering Sea could be problematic for ribbon seal reproduction as this species depends on the availability of offshore pack ice. Disruption or alteration of the patterns of Arctic primary productivity and abundance of key marine mammal prey species such as Arctic cod could also have detrimental effects on ice dependent seals (Tynan and DeMaster 1997). Pollock are an important spring ribbon seal food in the central and south central Bering Sea (Frost and Lowry 1980) and in the Sea of Okhotsk (Bukhtiyarov 1986). The effect of pollock harvesting on ribbon seals in the Bering Sea has not been examined, but competition with fisheries has been suggested as a possible limiting factor on population growth, or a threat that could result in declines (Reijnders 1993).
Comments: Some drown in commercial gill nets in the Bering Sea and North Pacific. Soviet commercial harvest in the Bering Sea in the 1960s resulted in a population decline there, probably from about 80,000-90,000 to around 60,000; later, a reduced harvest resulted in a population increase. In addition to commercial hunting from ships, potential threats include industrial offshore development and overharvesting of prey species (Reeves et al. 1992).
Relevance to Humans and Ecosystems
Economic Importance for Humans: Positive
Presently, very few are taken yearly, with those being taken for subsistence purposes by natives of the areas in which the seal lives. From the 1950's until the 1980's Russian fisheries killed large numbers of ribbon seals for their pelts, meat, and oil. Recently commercial hunting has been abandoned. (Meston, 1997)
Comments: Due to remote habitat, not regularly hunted by native peoples (but small subsistence harvest continues). Seal's lack of caution on the ice makes it vulnerable to commercial pelagic sealers. In the 1960s, the annual Soviet catch averaged about 13,000 and the population began to decline; lower quotas later resulted in a population increase (Nowak 1991).
The ribbon seal (Histriophoca fasciata) is a medium-sized pinniped from the true seal family (Phocidae). A seasonally ice-bound species, it is found in the Arctic and Subarctic regions of the North Pacific Ocean, notably in the Bering Sea and Sea of Okhotsk. It is distinguished by its striking coloration, with two wide white strips and two circles against dark brown or black fur.
Adult seals are recognizable by their black skin, which carries four white markings: a strip around the neck, one around the tail and a circular marking on each body side, which encloses the front fins. The contrast is particularly strong with the males, while with females the difference in color between bright and dark portions is often less conspicuous. Newborn ribbon seal pups have white natal fur. After moulting their natal fur, their color changes to blue-grey on their backs and silvery beneath; after some years some portions become darker and others brighter, and only at the age of four years does the typical design show.
The ribbon seal has a large inflatable air sac that is connected to the trachea and extends on the right side over the ribs. It is larger in males than in females, and it is thought that it is used to produce underwater vocalizations, perhaps for attracting a mate. The ribbon seal can grow about 1.6 m (5.2 ft) long, weighing 95 kg (209 lb) in both sexes.
The ribbon seal lives in the Arctic parts of the Pacific Ocean. During winter and spring, it hauls out on pack ice to breed, molt, and give birth. During this time, it is found at the ice front in the Bering and Okhotsk Seas. During the summer and autumn, the ribbon seal lives in open water, though some move north as the ice recedes with warmer temperatures. Little is known about its habit during this time, as it is so far from land and human observation. The ribbon seal almost never comes to land.
Thus far, there have been only two acknowledged instances where ribbon seals have been found as far south as Seattle, Washington and even further south at Morro Bay, California. There was nothing to suggest that illness was the cause of either seals appearance at either place, as both appeared to be healthy.
The diet of ribbon seal consists almost exclusively of pelagic creatures: fish like pollocks, eelpouts, the Arctic Cod and cephalopods such as squid and octopus; young seals eat crustaceans as well. The ribbon seal dives to depths of up to 200 m in search of food; it is solitary and forms no herds. Females reach sexual maturity at 2 to 5 years and males reach sexual maturity at 3 to 6 years, and an individual may reach twenty to twenty-five years of age. Mating takes place from late April to early May. Young animals are born on the ice in April and May. They are fed for four weeks on their mother's milk, then leave their mother. They remain on the ice for a few more weeks, in which they lose their dense white fur and lose a drastic amount of weight. After this period, they are able to dive and hunt by themselves.
Young ribbon seals look like young harp seals, and like these, they were hunted for their fur. Since they do not form herds, ribbon seals were more difficult to catch than harp seals. Since the Soviet Union limited the hunt on ribbon seals in 1969, their population has recovered. The current population is around 250,000.
In March 2008 the US government agreed to study Alaska's ribbon seal population and considered adding it to the endangered species list. However, in December 2008, the US government decided that sea ice critical to the seals' survival will not be endangered by global warming, and declined to list the species. Instead, it became a U.S. National Marine Fisheries Service Species of Concern. The US Government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service (NMFS), has some concerns regarding status and threats of some species, for which insufficient information is available to list them under the US Endangered Species Act.
- Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Burkanov, V. & Lowry, L. (2008). Histriophoca fasciata. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 29 January 2009.
- Berta, A. & Churchill, M. (2012). "Pinniped Taxonomy: evidence for species and subspecies". Mammal Review 42 (3): 207–234. doi:10.1111/j.1365-2907.2011.00193.x.
- Peter Saundry. 2010. Ribbon seal. Encyclopedia of Earth. C.Michael Hogan (Topic Editor). Cutler J. Cleveland, ed. National Council for Science and the Environment, Washington DC
- SCS: Ribbon Seal (Phoca fasciata)
- Rare sea creature appears on Seattle woman's dock.
- Govt: Ribbon seals not endangered. Associated Press. 23 December 2008
- Boveng, P.L. et al. (2008). Status Review of the Ribbon Seal (Histriophoca fasciata). Seattle, WA: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center.
Names and Taxonomy
Comments: Placed in the genus Histriophoca by Muizon (1982), Rice (1998), Baker et al. (2003), and some other authors, but regarded (with the nominal genera Pagophilus and PUSA) as a member of the genus Phocain other recent literature on pinnipeds (e.g., King 1983; Riedman 1990; Nowak 1991; Reeves et al. 1992; Wozencraft, in Wilson and Reeder 1993).
A cladistic analysis of mtDNA data yielded three clades among northern seals: Phoca-Pusa-Halichoerus, Cystophora-Pagophilus, and Erignathus (Perry et al. 1995). Each clade may be regarded as a tribe of the subfamily Phocinae. The magnitude of the differences among Phoca, Pusa, and Halichoerus was on the same order as that between species and subspecies within the genus Odocoileus. Because Cystophora is the closest relative of Pagophilus, the latter cannot be regarded as congeneric with Phoca; the differences between the two are great enough to justify placing them in separate genera (Perry et al. 1995).
Mouchaty et al. (1995) examined the cytochrome b gene and found a close phylogenetic relationship between Pagophilus groenlandicus and Histriophoca fasciata, consistent with earlier studies.