Reason for Ocean Optimism
Marine mammals, sea turtles listed under Endangered Species Act are recovering, study finds
Twenty years ago I started my scientific career as a college freshman in Cuba, collecting data to support sea turtle conservation. I was full of optimism. I was just learning about the threats that thousands of marine species and their habitat were facing due to human actions, and I still had hope that conservation measures laid out in my textbooks would help them.
On remote, protected beaches on the southeast coast of this Caribbean island, we camped for weeks during the summers, fighting voracious mosquitos and waiting for the arrival of nesting sea turtles. In just one nesting season we counted and measured hundreds of green and loggerhead sea turtles and recorded thousands of eggs and hatchlings.
These sea turtle populations were nesting in one of the most pristine coastal ecosystems of the island, and they were thriving. Reef fish, sharks and corals of the adjacent fringing coral reefs were also doing spectacularly — a dreamy seascape free from human impacts, further protected by national park status. Conservation was working.
Nowadays good news in marine conservation is rare or underreported. That’s why I’m so excited to be able to reveal that most marine mammals and sea turtles protected by the U.S. Endangered Species Act are recovering. Our study, which we released today as a preprint, found conservation measures helped boost the populations of marine species once headed for extinction.
It’s easy to get discouraged by stories of corals dying at unprecedented rates in the Great Barrier Reef. But wildlife population recoveries, after drastic declines, are great examples of success stories as marine species face growing threats from climate change, overfishing, pollution and other human activities.
Our findings are remarkable. The best available population data for 23 marine mammals and nine sea turtles shows that 78 percent of them — including most large whales, Florida manatees, California sea otters and green sea turtles — experienced substantial population increases after being protected by America’s landmark federal conservation law.
We did this. Working together, scientists, federal officials and members of the public created management plans, protected critical habitat, and set forth a series of crucial conservation measures to promote the recovery of these species.
Today people can see many more humpback and gray whales migrating along the West Coast. After many decades humpbacks and sperm whales have even been observed in the Salish Sea.
Southern sea otters are thriving in California coastal waters at record numbers. Nesting numbers of green, loggerhead and leatherback sea turtles across Florida have also broken estimated population records in the past few years.
Sharing good conservation stories give us hope. I’ve been studying and diving on coral reefs all my adult life, and I’ve experienced the decline of an entire, fragile planetary ecosystem. But there are still bright spots where corals and fish are thriving that we need to highlight.
The capacity of marine mammals and sea turtles to recover from threats is cause for hope. While sailing last year looking for killer whales in the Salish Sea, I was lucky enough to see one of the first humpback whales cruising around the San Juan Islands. I have seen leatherbacks laying hundreds of eggs in the beaches of Puerto Rico and Hawaiian monk seals swimming in the waters of West Hawaii.
The Endangered Species Act works. Our analysis shows we can still save whales and other endangered species if we just make the effort. In our study we found that species protected by the Act for more than 20 years were more likely to be recovering than recently listed species — a sign the Act is effective if federal officials follow its mandates.
Conservation measures triggered by the Act include habitat protections, science-based management measures and recovery planning. The Endangered Species Act has required devices that allow sea turtles to escape from fishing nets, protected whales from deafening sonar and reduced disorienting lighting from sea turtle nesting beaches, among other protections.
Although most marine mammals and sea turtles within U.S. waters are on the path to recovery, several species haven’t yet rebounded. Three species of marine mammals and two species of sea turtles remained unchanged after listing, which may indicate population stability.
Other marine mammals continue to struggle after years of protection. Southern Resident killer whales continue to decline after being listed due to prey reduction, marine noise and toxic pollutants. North Atlantic right whales have been declining recently, after years of population increases, due to entanglement in fishing gear and vessel strikes.
The Act works well when officials effectively use the tools it provides. Threats can be addressed, and substantially reduced, if we effectively support and fund conservation measures highlighted in recovery plans. Critically endangered Hawaiian monk seals, in decline over the past few decades, have recently increased in population abundance, likely due to stronger conservation measures across Hawaii.
We conservation scientists need to do more to highlight what’s working in marine conservation, even as we continue to report the gloom and doom stories flooding the scientific literature. We need to remain optimistic as we study and tackle the threats marine species are facing.
We’ve got to share #OceanOptimism stories.
