Marine mammals and turtles rebound after endangered species protections

A new study shows broad recovery but doesn’t dive into the problems that remain.

 

In the late 1970s, somewhere between 220,000 and 265,000 Steller sea lions swam, dove and fished in the western part of the Gulf of Alaska and the Bering Sea. But by the turn of the century, fewer than 50,000 remained.

By then, the pinnipeds had been protected under the Endangered Species Act. They were listed as threatened in 1990, and those living in the western gulf and the Bering Sea were later recategorized as endangered. That endangered population of sea lions has started to rebound: Though improvements haven’t been uniform across their range, their numbers grew by about a quarter between 2003 and 2015.

The population of Steller sea lions that lives in southeast Alaska has largely recovered and was delisted in 2013.

Those Steller sea lions are one of the more than 60 marine mammal and sea turtle populations sheltered by the Endangered Species Act since its inception in 1973. Now, new peer-reviewed research conducted by scientists from the Center for Biological Diversity, a conservation-focused nonprofit, suggests that protection has largely been effective, with a paper title that succinctly sums up their findings: “Marine mammals and sea turtles listed under the U.S. Endangered Species Act are recovering.”

To measure the impact of the Endangered Species Act, the researchers analyzed how population numbers shifted after listings. For 31 protected marine mammals and sea turtles — a subset of species that met certain criteria, including living and reproducing mostly in U.S. waters, and for which enough data were available to measure changes — the scientists determined whether the population grew larger, stayed the same, or shrank. They found that about three-quarters of the marine mammal and sea turtle populations increased after listing. “We just need to put our effort into it in order to protect these species,” said Abel Valdivia, the lead author of the study, who now works for RARE, a conservation group based in Arlington, Virginia. “They do have a really high capacity for rebounding if some conservation measures are put in place.”

A wide-ranging look at different animals can be a good way to answer general questions about the impact of conservation measures, said Lorrie Rea, an ecotoxicologist at the University of Alaska Fairbanks who researches Steller sea lions. But, she added, “The difficulty of looking at such a broad sweep is that it’s hard to catch the detail of any of the particular species.”

Take, for example, Steller sea lions. Though the population in the Bering Sea and the western Gulf of Alaska is doing better overall since being listed under the Endangered Species Act, some groups, particularly in the western and central Aleutian Islands, aren’t recovering.

That suggests that the fishing regulations that followed the listing — largely meant to keep fishing vessels from competing with sea lions for the fish they’re both trying to catch, and to protect the animals from the disturbance of loud, exhaust-spewing boats when they’re busy rearing young pups — are not addressing every cause of the sea lion declines. “We think there are other factors at play that are much more difficult to mitigate with regulation,” Rea said, including harmful environmental contaminants like mercury.

Another factor that may be boosting sea lion numbers in some places is natural variation in ocean conditions, which can affect what types of fish are available for them to eat, said Andrew Trites, the director of the marine mammal research unit at the University of British Columbia. In other words, it’s a mistake to assume that every species’ revival is due solely to human actions.

And while most populations improved following protections, a few did not, like coastal Washington’s southern resident killer whales. “(That) tells us that the world doesn’t work as simply as we thought it did,” Trites said. Some conservation measures, for example, may not be addressing the root causes of a population’s decline, like widespread pollution problems and changing ocean conditions. Still, the overall trend across North America is toward recovery, and for most marine mammals and sea turtles, that has a lot to do with Endangered Species Act protections that keep them from being hunted, accidentally caught in fishing gear or otherwise killed. “For the most part,” Trites said, “if you stop killing marine mammals and turtles, they can recover and do quite well.”

Emily Benson is an assistant editor at High Country News, covering the northwest, the northern Rockies and Alaska. Email her at [email protected] or submit a letter to the editor

High Country News Classifieds
  • PUBLIC LANDS PROGRAM MANAGER
    Conserve Southwest Utah is seeking a candidate with excellent communication skills and a commitment to environmental conservation for the position of Public Lands Program Manager....
  • EXECUTIVE DIRECTOR
    The Western Slope Conservation Center in Paonia, CO, seeks a dynamic leader who is mission-driven, hardworking, and a creative problem-solver. WSCC is committed to creating...
  • PLANNED GIVING OFFICER
    National Parks Conservation Association (NPCA), the nation's oldest and largest national parks nonprofit advocacy organization seeks a Planned Giving Officer. Do you find energy in...
  • NORTHERN NEW MEXICO PROJECT MANAGER
    Seeking qualified Northern New Mexico Project Manager to provide expertise, leadership and support to the organization by planning, cultivating, implementing and managing land conservation activities,...
  • REGIONAL TRAIL STEWARDSHIP COORDINATOR
    Are you passionate about connecting people to the outdoors? The Pacific Crest Trail Association (PCTA) is looking for someone with trail maintenance and volunteer engagement...
  • TRAIL CREW MEMBER
    Position Title: Trail Crew Member Position Type: 6 month seasonal position, April 17-October 15, 2023 Location: Field-based; The RFOV office is in Carbondale, CO, and...
  • CEO BUFFALO NATIONS GRASSLANDS ALLIANCE
    Chief Executive Officer, Remote Exempt position for Buffalo Nations Grasslands Alliance is responsible for the planning and organization of BNGA's day-to-day operations
  • IDAHO DIRECTOR - WESTERN WATERSHEDS PROJECT
    Western Watersheds Project seeks an Idaho Director to continue and expand upon WWP's campaign to protect and restore public lands and wildlife in Idaho, with...
  • DIRECTOR OF DEVELOPMENT, NA'AH ILLAHEE FUND
    Na'ah Illahee Fund (NIF) is seeking a highly qualified Development Director to join our team in supporting and furthering our mission. This position will create...
  • DIRECTOR OF OPERATIONS, NA'AH ILLAHEE FUND
    Na'ah Illahee Fund (NIF) is seeking a highly qualified Operations Director to join our team. This position will provide critical organizational and systems support to...
  • DEVELOPMENT DIRECTOR
    Grand Staircase Escalante Partners (GSEP) is seeking a leader to join our dynamic team in the long-term protection of Grand Staircase-Escalante National Monument (GSENM). We...
  • GRASSLAND RESEARCH COORDINATOR
    The Grassland Research Coordinator is a cooperative position with the U.S. Fish and Wildlife Service that performs and participates in and coordinates data collection for...
  • HYDROELECTRIC PLANT
    1.3 MW FERC licensed hydroelectric station near Taylorsville CA. Property is 184 deeded acres surrounded by National Forrest.
  • "PROFILES IN COURAGE: STANDING AGAINST THE WYOMING WIND"
    13 stories of extraordinary courage including HCN founder Tom Bell, PRBRC director Lynn Dickey, Liz Cheney, People of Heart Mountain, the Wind River Indian Reservation...
  • GRANT WRITER
    JOB DESCRIPTION: This Work involves the responsibility of conducting research in the procurement of Federal, State, County, and private grant funding. Additional responsibilities include identifying...
  • ASPIRE COLORADO SUSTAINABLE BODY AND HOME CARE PRODUCTS
    Go Bulk! Go Natural! Our products are better for you and better for the environment. Say no to single-use plastic. Made in U.S.A., by a...
  • CANYONLANDS FIELD INSTITUTE
    Field seminars for adults in the natural and human history of the Colorado Plateau, with lodge and base camp options. Small groups, guest experts.
  • ATTORNEY AD
    Criminal Defense, Code Enforcement, Water Rights, Mental Health Defense, Resentencing.
  • LUNATEC HYDRATION SPRAY BOTTLE
    A must for campers and outdoor enthusiasts. Cools, cleans and hydrates with mist, stream and shower patterns. Hundreds of uses.
  • LUNATEC ODOR-FREE DISHCLOTHS
    are a must try. They stay odor-free, dry fast, are durable and don't require machine washing. Try today.