Caribbean Monk Seal: Gone but Not Forgotten

Caribbean monk seal.

Credit: Henry W. Elliott

by Kyle Baker

On October 28, 2008, the National Marine Fisheries Service (NMFS) confirmed the extinction of the Caribbean monk seal (Monachus tropicalis) and removed it from the federal list of endangered and threatened wildlife. This makes it the first species of seal to go extinct as a direct result of human activities.

It was the only seal native to the wider Caribbean region, including Florida and the Gulf of Mexico. Until recently, reports of seal sightings within the species’ range led to hope that some monk seals may have persisted around remote reefs in the Caribbean. To resolve any lingering doubts, NMFS launched a formal status review. Completed in March 2008, the status review considered sighting reports, surveys, and marine mammal stranding data. Although some sightings from the late 1950s to the 1970s may have been solitary Caribbean monk seals, we have found that reported seal sightings in recent decades were all extra-limital (out of normal range) occurrences of hooded seals (Cystophora cristata), feral California sea lions (Zalophus californianus), misidentified manatees (Trichechus manatus), and other species.

It is remarkable how the Caribbean monk seal population, which likely numbered between 233,000 and 338,000 individuals among 13 major colonies, became extinct so rapidly following European colonization. Vulnerable due to their hauling-out behavior and abundant numbers, Caribbean monk seals were hunted as a readily available source of oil by European colonizers, and they were killed in lesser numbers for food. Intensive exploitation led to a rapid decline in seal numbers, extirpation of colonies, and population fragmentation. As the species became rare in the late 1800s and early 1900s, remaining seal colonies were targeted by expeditions to obtain dead specimens for scientific study and live animals for captive display. Expeditions of collectors to the Triangle Keys region of the Yucatan Peninsula in the early 1900s led to the extirpation of what may have been the last remaining large colony in the wild. Ironically, the hundreds of seals killed during this period due to scientific interest in the species may have sealed its fate.

A captive Caribbean monk seal at the New York Aquarium in 1910. Four specimens were purchased in 1909 from a dealer in Mexico who captured the animals from islands or reefs off the Yucatán Peninsula.

Photo Credit: New York Zoological Society

We cannot be certain when the Caribbean monk seal vanished, but the last confirmed sighting was of a small colony on an isolated reef at Serranilla Bank (a group of small uninhabited islands in the southern Caribbean) in 1952. Many efforts were made to locate remaining seals in the wild, but their occurrence was never again confirmed, and all captive specimens died long ago.

Hunting and collection of Caribbean monk seals was never regulated in time to save the species. The locations of any remaining seals were unknown by the time conservation actions were finally considered. Very little is known of the seal’s life history, ecology, and behaviour. However, we believe that, as human settlement expanded in areas inhabited by this species, persistent hunting reinforced evasive seal behaviors, and avoidance of humans likely caused seals to abandon historic haul-out sites.

Lessons Learned

We hope the extinction of the Caribbean monk seal marks the end of the era when unbridled hunting and collection can endanger a species in the wild. The Caribbean monk seal is not the only seal species that was decimated by overhunting in the past. After only about 50 years of commercial hunting for their blubber in the 1800s, northern elephant seals (Mirounga angustirostris) nearly became extinct. Fortunately, the northern elephant seal population recovered remarkably well following an international hunting ban in 1911. In retrospect, we know that proper management and enforcement of sealing and whaling could have prevented the depletion of many marine mammals that are threatened and endangered today, and in the worst cases, the extinction of several species.

Currently, two species of monk seals remain—the Hawaiian monk seal (Monachus schauinslandi) and the Mediterranean monk seal (Monachus monachus). Both are listed under the Endangered Species Act (ESA) and are in serious decline. Other seals listed under the ESA are the Steller sea-lion (Eumetopias jubatus), Guadalupe fur seal (Arctocephalus townsendi), and Saimaa seal (Phoca hispida saimensis). NMFS completed a status review of ribbon seals (Histriophoca fasciata) in December 2008, and is currently reviewing the status of three other species: bearded seals (Erignathus barbatus), ringed seals (Phoca fasciata), and spotted seals (Phoca largha).

The scarcity of information and lack of management leading to the extinction of Caribbean monk seals spotlights the need for continued support of monitoring programs, research, and cooperation among stakeholders in the recovery of seal populations today. We know that conserving seals is no longer as simple as ending overharvesting. We face new conservation challenges associated with habitat loss, global climate change, overfishing, human interactions, and the cumulative effects of many factors affecting ecosystems. The overall health of ecosystems is crucial to the survival of these species, and monitoring and adaptive management strategies, as well as enhanced partnerships, are integral components of recovery plans.

The conspicuous absence of monk seals from tropical reef ecosystems in the wider Caribbean region is a permanent reminder of the tough research and management challenges we are certain to face in the future. Our ability and willingness to meet these challenges will determine if we are able to save our remaining species from the fate of the Caribbean monk seal.

Kyle Baker, a fishery biologist on the marine mammal team in the NMFS Southeast Regional Office, can be reached at 727-824-5312 or kyle.baker@noaa.gov.