|Graph of Leatherback populations in the Eastern Pacific over time (Data from Las Baulas National Park, Costa Rica).|
Eastern Pacific Leatherbacks Face Extinction Without Focused, Effective Conservation
It's hard to believe the stories told by old-timers who have lived for decades near Playa Grande, Costa Rica. According to the people living in the area during the 1970s and 1980s, there were so many leatherbacks nesting on Playa Grande and the adjacent beaches Playa Langosta and Playa Ventanas that the locals referred to them as 'hormigas,' or ants. Try to imagine so many leatherbacks, with their expansive flipper-span of 8-10 feet and weight of half a ton, that people compared them to multitudinous, industrious insects.
What makes this hard to believe is that since that time during which the beaches resembled leatherback "anthills," the number of nesting leatherbacks has declined more than 90%. Put another way, more than a hundred individual turtles would nest on a given night during the peak of the nesting season twenty years ago; in contrast, the total number of nesting females in an entire five-month season has exceeded 100 only four times in the past decade. Unfortunately, this population decline has not been confined to Pacific Costa Rica; the same precipitous drop has been observed in the Mexican leatherback nesting population as well. Significant steps must be taken to address threats to leatherbacks in the region to avoid extinction of this population.
What caused the collapse?
It is clear now that a combination of environmental variability and unsustainable human-caused (termed "anthropogenic") impacts have resulted in the population decline. Unmitigated and often lethal interactions between leatherbacks and fishing gear throughout their vast geographic range likely resulted in high rates of leatherback mortality. In addition, almost complete egg harvest – i.e. greater than 90 percent of eggs laid were sold for human consumption – occurred for the better part of two decades.
Underlying these human impacts is a strong environmental influence. Resource (i.e. food) availability in the eastern Pacific is less predictable and abundant than in other ocean areas where other populations of leatherbacks feed. Thus, environmental variability in the eastern Pacific has made leatherbacks more vulnerable to anthropogenic threats, which has resulted in a swift and simultaneous decline in leatherbacks along the entire coast of the Pacific Americas.
PUBLICATION: Variations in Leatherback Turtles
As if leatherbacks weren't already facing immense challenges to their survival, the specter of coastal development now looms dark over Playa Grande and adjacent beaches, their preferred nesting sites. There is currently an intense struggle between conservation groups and developers over the fate of the beachfront land backstopping the most important stretch of beach for leatherbacks in the entire region.
Parks and Research Provide Hope for Leatherbacks
Although the situation might look bleak for leatherbacks, there are glimmers of hope for their future. Playa Grande, Playa Ventanas, and Playa Langosta were designated as Las Baulas (Spanish word for leatherbacks) National Marine Park in 1995, and full protection by Park Rangers and biologists has virtually eliminated egg harvest at these sites. The Park also attracts thousands of national and international tourists each year, bringing new sources of revenue into the local communities as well as into the Costa Rican national park system.
In addition, a population monitoring project has been in place since the late 1980s, which has become a fixture in the local, national, and scientific communities. Satellite tracking studies have described a persistent migratory pattern demonstrated by leatherbacks, which greatly informs regional conservation strategies for managing fisheries.
IN DEPTH: Learn more about this satellite tracking research.
In addition, biologists have recently observed a sizeable proportion of 'new' turtles each season, which indicates that conservation efforts to protect nesting leatherbacks and their beach habitat are beginning to pay off.
One non-governmental organization, The Leatherback Trust, has been engaged in leatherback conservation from the nesting beach to the halls of Costa Rican government. The Leatherback Trust, with bases in both the U.S. and Costa Rica, has been working for more than seven years to ensure protection of the beachfront land within the National Park and to support the on-the-ground conservation efforts of the biologists and the Park Rangers.
Undoubtedly, the situation for leatherbacks in the eastern Pacific is dire. Meaningful, swift conservation action is critical to secure a future for leatherbacks in this region. While the future remains unclear, the situation for leatherbacks at Las Baulas National Park, and the rest of the eastern Pacific, depends on how the groups involved respond to the challenges and opportunities. In light of the long history of humans and leatherbacks in the eastern Pacific, conservation efforts are underway to ensure that future generations of people and turtles will continue to call the area home.
LEARN MORE: Find out why leatherback sea turtles are a record-setting species.