Guadalupe Fur Seal
About the Species
Guadalupe fur seals are members of the “eared seal” family, Otariidae. Their breeding grounds are almost entirely on Guadalupe Island, off the Pacific coast of Mexico, with recent re-colonization off the San Benito Archipelago. A small number of Guadalupe fur seals have also been reported on the northern Channel Islands off California.
Commercial sealers heavily hunted Guadalupe fur seals in the 1700s to the 1800s until they were thought to be extinct in the early 1900s. Dr. Hubbs and Dr. Bartholomew from the University of California rediscovered them breeding in a cave on Guadalupe Island in 1954. The Guadalupe fur seal population has continued to increase from the small remnant group on Guadalupe Island due to protection by the Mexican Government. Guadalupe fur seals are listed as threatened under the Endangered Species Act and depleted under the Marine Mammal Protection Act.
NOAA Fisheries and its partners (including researchers and conservation managers in Mexico) are dedicated to conserving and promoting the recovery of the Guadalupe fur seal population. Researchers use innovative techniques to study and protect this species. For example, they use satellite telemetry to assess movement patterns and foraging activities, interactions between Guadalupe fur seals and fisheries, and their vulnerability to oil spills. This work helps reduce harm from human activities (e.g. fishing) through management based on sound science, public input, and outreach and education.
The Guadalupe fur seal population has been growing at approximately 10 percent between 1955 and and 2010. Based on surveys conducted between 2008 and 2010 was estimated at approximately 20,000 animals, thanks to protection under Mexican and U.S. laws.
- Throughout Its Range
- Throughout Its Range
- Throughout Its Range
Guadalupe fur seals have narrow, flat heads with pointed, narrow, long snouts. Their fore-flippers are broad, with some hair, reaching past their wrists and forming a "V" on the foreflipper. Their coloration is dark brown. Adult males have tan or yellow hairs on the back of the mane. Adult males are considerably longer and larger-bodied than adult females.
Behavior and Diet
Guadalupe fur seals are generally solitary, are thought to be non-social animals when at sea. They primarily feed at night on coastal and pelagic squid, and small pelagic fish (e.g., mackerel,sardine, and lanternfish) by diving to average depths of 65 feet with maximum depths of about 250 feet.
They rest in the water with their heads below water and their hind-flippers jutting out.
Where They Live
Guadalupe fur seals live in the waters off southern California and the Pacific coast of Mexico. During the breeding season, they are found in coastal rocky habitats and caves. Little is known about their whereabouts during the non-breeding season.
Guadalupe fur seals generally do not migrate, although they have been documented traveling great distances from their breeding grounds. Their breeding grounds are almost entirely on Guadalupe Island, Mexico, although there are small populations off Baja California on San Benito Archipelago and off southern California at San Miguel Island. It is the only species of the Arctocephalus genus that occurs north of the equator.
Guadalupe fur seals are not common along the West Coast of the United States, but immature animals commonly strand on beaches as far north as Washington State. Over the last several years, a few pups have been born on San Miguel Island in the Channel Islands off southern California.
From archeological findings Guadalupe fur seals were historically found as far north as the northwest Washington coast.
Lifespan & Reproduction
Guadalupe fur seals' breeding season extends from June through August. Adult males return to the colonies during early June. They set up territories that they defend through aggression and vocalizations when challenged or threatened by other males. Breeding Guadalupe males are polygamous and may mate with up to 12 females during a single breeding season. Adult females arrive to the colonies in early June, giving birth a few days later. Pups are born from early June through early July, with a peak in late. Pups are born from early June through early July, with a peak in late June.
An adult female will mate about a week after giving birth to her pup. Weaning occurs around 9 months.
We have very limited data on the incidental bycatch of Guadalupe fur seals in fishing gear, although some pups and juvenile seals have been documented as entangled, through strandings or fisheries observations. If a fur seal becomes entangled in fishing gear, the animal risks either swimming off with the gear attached or becoming anchored. Once entangled, Guadalupe fur seals may drag and swim with gear attached for long distances, ultimately resulting in fatigue, compromised feeding ability, or severe injury, which may lead to reduced reproductive success and death.
Guadalupe fur seals are affected by military activities off the U.S. west coast, including readiness training for personnel and their associated fleets and battalions, and construction and maintenance of land-based and island-based facilities. Some of the military training exercises include the use of mid-frequency active sonar for submarine detection, placement and detection of small explosives in coastal waters, open-ocean target practice using high powered guns, ship-shock tests, and other more small-scale exercises. These activities threatened Guadalupe fur seals through increased ocean noise and vessel strikes.
Fur seals rely on their thick layer of fur to insulate their bodies from the cold marine environment. Oil spills pose a threat to this species by affecting the ability of their fur to keep them warm. Guadalupe fur seals rarely strand in southern California, and only recently have we received reports of stranded yearlings, with most of them emaciated or dead. Based on a review of our stranding reports over the last 30 years, there have been no reports of Guadalupe fur seals that have ingested oil or have an oiled pelage.
Noise associated with coastal development (e.g., pile driving, dredging, and vessels transporting personnel) could disturb Guadalupe fur seals and cause them to avoid areas temporarily, and may even cause temporary or permanent hearing loss.
The Guadalupe fur seal was listed as threatened throughout its range in December 1985, under the Endangered Species Act of 1973. It is also protected under the Marine Mammal Protection Act of 1972, as amended, which also designates the species as strategic and depleted, due to their listing as threatened under the ESA. In 1928, the government of Mexico declared Guadalupe Island a pinniped sanctuary and in 1967 banned the hunting of Guadalupe fur seals.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings. 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.
Reducing Interactions with Fishing Gear
Guadalupe fur seals can become incidentally entangled in fishing gear, which may cause injury and possibly death. NOAA Fisheries is working to better understand and characterize the frequency, geographic extent, and magnitude of these interactions. We are also working with scientists to research potential solutions to safely and effectively reduce these interactions.
Educating the Public
NOAA Fisheries aims to increase public awareness and support for Guadalupe fur seal conservation through education, outreach, and public participation. We regularly share information with the public about the status of fur seals, as well as our research and efforts to promote their recovery.
The Guadalupe fur seal was listed as threatened throughout its range in December 1985, under the Endangered Species Act of 1973; it is also protected under the Marine Mammal Protection Act of 1972, as amended.
In 1975, the government of Mexico declared Guadalupe Island a pinniped sanctuary.
NOAA Fisheries has classified the U.S. Guadalupe fur seal stock as a “strategic” stock.
Regulatory Actions & Documents
NOAA Fisheries researches the biology, behavior, and ecology of the Guadalupe fur seal. We use the results to inform management decisions and recovery efforts for this threatened species.
Determining the number of Guadalupe fur seals in their population—and whether a stock is increasing or declining over time—helps resource managers assess the success of conservation measures. Our scientists collect information and present these data in annual stock assessment reports.
Unusual Mortality Events
To understand the health of Guadalupe fur seal populations, scientists study unusual mortality events (UMEs). Marine mammal UMEs are important because they can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare. Since 2015, an elevated number of strandings of Guadalupe fur seals have occurred along the entire coast of California. Strandings in January 2015 were eight times higher than the historical average. They have remained well above the average through 2017. This ongoing event was declared a UME in 2015.