About the Species
The spotted seal gets its name from its coat pattern, which is usually a light-colored background with dark spots. Spotted seals are widely distributed on the continental shelf of the Beaufort, Chukchi, southeastern East Siberian, Bering, and Okhotsk Seas; south through the Sea of Japan; and into the northern Yellow Sea. From late fall through spring, spotted seal habitat use is primarily associated with seasonal sea ice. Most spotted seals spend the rest of the year making periodic foraging trips from haulout sites onshore or on sea ice. Spotted seals are unusual among true seals in that they annually form "family" groups consisting of a female, a male, and a pup during breeding season.
Spotted seals rely on sea ice during reproduction and to some extent during molting. As such, they are sensitive to changes in the environment that affect the annual timing and extent of sea ice formation and breakup.
Spotted seals, like all marine mammals, are protected under the Marine Mammal Protection Act. There is one recognized stock of spotted seals in U.S. waters: the Alaska stock. One distinct population segment of spotted seals outside U.S. waters (the southern DPS)—with breeding concentrations in the Yellow Sea and the Sea of Japan—is listed as threatened under the Endangered Species Act. Because of its listed status, this DPS is also designated as depleted under the MMPA.
No accurate range-wide abundance estimates exist for spotted seals. Based on crude estimates available in historic literature, the worldwide population of spotted seals is estimated to be more than 500,000 individuals.
There is one recognized stock of spotted seals in U.S. waters: the Alaska stock. Abundance estimates for this stock are provided in the stock assessment report.
Historically, subsistence harvest of spotted seals has been moderately low and is not anticipated to increase significantly. While the United States does not allow the commercial harvest of marine mammals, such harvests are permitted in some other portions of the species’ range. Based on available data, these harvests are not thought to have been high enough historically to cause significant reductions in abundance and appear to be generally limited.
ESA Threatened - Foreign
- Southern DPS
- Throughout Its Range
- Southern DPS
Spotted seals have a round head, narrow snout, and small body, as well as narrow, short flippers. Adult spotted seals are silvery-gray to light gray with dark spots scattered densely on their body. Pups are born with a white coat that is usually shed at the time of weaning and replaced with a coat that is rather similar to adults. Spotted seals grow to average lengths of 5 feet, with weights ranging from 140 to 250 pounds. Males and females are generally similar in appearance. Spotted seals are closely related and often confused with harbor seals in areas where you can find both, such as in Bristol Bay, Alaska.
Behavior and Diet
Spotted seals prefer arctic or sub-arctic waters and are often found within the outer margins of shifting ice floes. They rarely inhabit areas of dense pack ice. During breeding season, spotted seals primarily haul out on ice floes, whereas during the summer months they can be found in the open ocean or hauled out on shore.
Spotted seals consume a broad variety of mostly fishes and some crustaceans and cephalopods. While regional differences in the diet of spotted seals are noted among studies, some prey items are important across almost the entire range of the species. Pacific herring and crustaceans are major prey in all locations except the central Bering Sea, and walleye pollock is important in all regions except the Chukchi Sea. Overall, younger animals predominantly consume crustaceans, and older seals mainly eat fish. Spotted seals are not deep divers and feed almost exclusively over the continental shelf in waters less than 650 feet deep.
Where They Live
Spotted seals live in the waters of the North Pacific Ocean. They are widely distributed on the continental shelf of the Beaufort, Chukchi, southeastern East Siberian, Bering, and Okhotsk Seas; south through the Sea of Japan; and into the Yellow Sea.
In U.S. waters, spotted seals migrate south from the Chukchi Sea through the Bering Strait from October to November ahead of advancing sea ice. They spend the winter in the Bering Sea in the annual pack ice over the continental shelf. During spring, they migrate to coastal habitats after the sea ice retreats.
Lifespan & Reproduction
Nearly all spotted seals reach sexual maturity by the time they are 5 years of age. Spotted seal pups are born anytime from January through April, depending on their location. The pupping and nursing season occurs earliest (January through early March) in the Yellow Sea and latest (late March through May) in the Sea of Okhotsk and Bering Sea, with a peak of pup births in the Bering Sea in early to mid-April. Females mate shortly after their pups are weaned. Males are thought to be annually monogamous, and spotted seals form "family" groups consisting of a female, male, and a pup during breeding season. Gestation lasts for just over 10 months. Their maximum lifespan is 30 to 35 years.
Pups are white and weigh 15 to 26 pounds at birth. They are nursed for 3 to 6 weeks, during which time they more than triple in weight. Pups born on the sea ice rarely enter the water until they are weaned and molted. During the first few weeks after weaning, pups remain at least partially dependent on ice while they become proficient at diving and foraging for themselves.
Spotted seals are primarily associated with sea ice during reproduction and molting. As such, spotted seals are sensitive to changes in the environment that affect the timing and extent of sea ice formation and breakup. In particular, loss of sea ice habitat poses a significant threat to the Southern distinct population segment of spotted seals, which breeds in the Yellow Sea and Peter the Great Bay in the Sea of Japan.
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 spotted 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 spotted seals. The most significant risk posed that these activities pose is accidentally or illegally discharging oil or other toxic substances, which would have immediate and potentially long-term effects. Spotted seals could also be directly affected by noise and physical disturbance of habitat associated with such activities.
All marine mammals, including spotted seals, are protected under the Marine Mammal Protection Act of 1972 as amended. The southern distinct population segment of spotted seals, which lives in the Yellow Sea and Sea of Japan, is listed as threatened under the Endangered Species Act and is designated as depleted under the MMPA because of its ESA listing.
Alaska Natives have a long history of self-regulation to ensure a sustainable take of marine mammals for food and handicrafts.
In 1994, the MMPA was amended to section 119, which reads, “The Secretary map enter into cooperative agreements with Alaska Native Organizations to conserve marine mammals and provide co-management of subsistence use by Alaska Natives.” These co-management agreements may be established between NOAA Fisheries or the U.S. Fish and Wildlife Service and Alaska Native Organizations, including (but not limited to) Alaska Native tribes and tribally authorized co-management bodies. Co-management promotes full and equal participation by Alaska Natives in decisions affecting the subsistence management of marine mammals (to the maximum extent allowed by law) as a tool for conserving marine mammal populations in U.S. waters in and around Alaska.
NOAA Fisheries entered into a co-management agreement with the Ice Seal Committee in October 2006. The Ice Seal Committee is an Alaska Native Organization that represents ice seal subsistence users in the five regions of Alaska that harvest ice seals: Bristol Bay (Bristol Bay Native Association), Yukon-Kuskokwim Delta (Association of Village Council Presidents), Bering Sea (Kawerak, Inc.), Northwest Arctic (Maniilaq Association), and the Arctic Slope (North Slope Borough). The Ice Seal Committee is dedicated to conserving ice seal populations, habitat, and hunting and to preserving native cultures and traditions. The Ice Seal Committee co-manages ice seals with NOAA Fisheries by monitoring subsistence harvest and cooperating on needed research, and education programs pertaining to ice seals.
For additional information about ice seals, co-management, and the status of ice seal species under the ESA read the Ice Seals: Frequently Asked Questions (PDF, 2 pages). These FAQs are also available in a larger page layout (PDF, 1 page).
The Ice Seal Committee adopted an Ice Seal Management Plan (PDF, 8 pages) in January 2012 that outlines the members’ management principles and goals.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings including large whales. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health. When stranded animals are found dead, our scientists work to understand and investigate the cause of death. Although the cause often remains unknown, scientists can sometimes identify strandings due to disease, harmful algal blooms, vessel strikes, fishing gear entanglements, pollution exposure, and underwater noise. Some strandings can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.
Declaring an Unusual Mortality Event in Northern Alaska
We declared a disease outbreak in northern Alaska ice seals an unusual mortality event in 2011.
To understand the health of ice seal populations, our scientists work with our stranding network partners to collect data on all marine mammal strandings and investigate UMEs. UMEs can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.
Spotted seals, like all marine mammals, are protected under the MMPA.
On October 20, 2009, NOAA Fisheries announced its completion of a comprehensive status review of the spotted seal (PDF, 169 pages) under the ESA and issued a 12-month finding on a petition to list the species as threatened or endangered under the ESA (PDF, 144 pages). NOAA Fisheries concluded that the spotted seal exists as three distinct population segments: the southern, Okhotsk, and Bering DPSs. As part of its 12-month finding, NOAA Fisheries issued a proposed rule to list the southern DPS of spotted seals, which consists of breeding concentrations in the Yellow Sea and Peter the Great Bay in the Sea of Japan, as threatened under the ESA. We determined that listing the Okhotsk DPS (consisting of breeding populations in the Sea of Okhotsk and Tatar Strait) and the Beringia DPS (consisting of breeding populations in Kariginsky Bay, the Gulf of Anadyr, and the Bering Sea) was not warranted at that time. On October 22, 2010, we published a final rule to list the southern DPS as threatened under the ESA.
Key Actions & Documents
- Final Rule (75 FR 65239)
- Proposed Rule and 12-month Finding (74 FR 53683)
- Notice of Initiation of Status Review (73 FR 16617)
NOAA Fisheries conducts a variety of research on the biology, behavior, and ecology of spotted seals. The results of this research are used to inform management decisions and enhance protection efforts for this species.
Our scientists collect information on spotted seals from various sources and present these data in an annual stock assessment report. Stock assessment reports contain scientific information on a species’ or stock’s geographic range, population structure, abundance, and threats, which helps resource managers assess the success of enacted management and conservation measures.
Ice Seal Surveys
Reliable distribution and abundance estimates for ice-associated seals are vital for developing sound plans for management, conservation, and responses to potential environmental impacts. NOAA Fisheries’ Marine Mammal Laboratory Polar Ecosystems Program designs and conducts surveys and uses the results to develop data products to address this fundamental information need. Additional information about the program’s research is available in recent reports and publications.
Molecular genetic techniques are being applied to a number of taxonomic, evolutionary and demographic questions in all ribbon, ringed, spotted, and bearded seals, including the relationships among the different species and the population structure and dispersal patterns within each species.
NOAA’s Southwest Fisheries Science Center and the Alaska Department of Fish and Game are currently involved in a long-term study of the population structure within spotted seals and the evolutionary and contemporary relationship of this species to the morphologically similar harbor seal. Analysis of variation within their mitochondrial DNA confirmed that these two seals were indeed separate species. More recent research has detected population structure in spotted seals only over very large (>620 miles) distances and has documented several individuals that, although identified as harbor seals in the field, turned out to have the spotted seal genetic signature. NOAA Fisheries recently initiated a collaborative research project with the Alaska Department of Fish and Game to determine whether mitochondrial DNA would help resolve questions of population and stock structure in ringed, bearded and ribbon seals. Initial efforts are revealing high levels of genetic variation in all species.
The Polar Ecosystems Program’s ongoing research on abundance, distribution, migration, and foraging behavior of spotted seals in Alaska helps us to understand their role of spotted seals in the marine ecosystem and inform management decisions for the conservation of this species.
Alaska Region Marine Mammal Stranding Network Newsletter
Alaska Region Marine Mammal Stranding Network Newsletter