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
  • DISTRICT MANAGER
    The San Juan Islands Conservation District is seeking applicants for the District Manager position. The position is open until filled and application plus cover letter...
  • EXECUTIVE DIRECTOR
    Mountain Time Arts, a Bozeman-based nonprofit, is seeking an Executive Director. MTA advocates for and produces public artworks that advance social & environmental justice in...
  • BEND AREA HOME WITH AMAZING CASCADE PEAKS VIEW
    Enjoy rural peacefulness and privacy with one of the most magnificent Cascade Mountain views in sunny Central Oregon! Convenient location only eight miles from Bend's...
  • MARKETING COMMUNICATIONS MANAGER
    High Country News, an award-winning media organization covering the communities and environment of the Western United States, seeks a Marketing Communications Manager to join our...
  • EDITOR-IN-CHIEF
    High Country News, an award-winning media organization covering the communities and environment of the Western United States, seeks an Editor-In-Chief to join our senior team...
  • RESEARCH FELLOW (SOUTHWESTERN U.S. ENERGY TRANSITION)
    The Institute for Energy Economics and Financial Analysis (IEEFA) in partnership with the Grand Canyon Trust is seeking a full-time Fellow to conduct topical research...
  • LENDER OWNED FIX & FLIP
    2 houses on 37+ acres. Gated subdivision, Penrose Colorado. $400k. Possible lender financing. Bob Kunkler Brokers Welcome.
  • ONCE OR TWICE
    A short historical novel set in central Oregon based on the the WWII Japanese high altitude ballon that exploded causing civilian casualties. A riveting look...
  • HISTORIC LODGE AND RESTAURANT - FULLY EQUIPPED
    Built in 1901, The Crazy Mountain Inn has 11 guest rooms in a town-center building on 7 city lots (.58 acres). The inn and restaurant...
  • HOUSE FOR SALE
    Rare mountain property, borders National Forest, stream nearby. Pumicecrete, solar net metering, radiant heat, fine cabinets, attic space to expand, patio, garden, wildlife, insulated garage,...
  • COMMUNITY ORGANIZER- NORTHERN PLAINS RESOURCE COUNCIL
    Want to organize people to protect Montana's water quality, family farms and ranches, & unique quality of life with Northern Plains Resource Council? Apply now-...
  • CONSERVATION MANAGER
    The Rio Grande Headwaters Land Trust (RiGHT) is hiring an energetic and motivated Conservation Manager to develop and complete new conservation projects and work within...
  • POLLINATOR OASIS
    Seeking an experienced, hardworking partner to help restore a desert watershed/wetland while also creating a pollinator oasis at the mouth of an upland canyon. Compensation:...
  • ELLIE SAYS IT'S SAFE! A GUIDE DOG'S JOURNEY THROUGH LIFE
    by Don Hagedorn. A story of how lives of the visually impaired are improved through the love and courage of guide dogs. Available on Amazon.
  • COMING TO TUCSON?
    Popular vacation house, furnished, 2 bed/1 bath, yard, dog-friendly. Lee at [email protected] or 520-791-9246.
  • NORTHEASTERN UNIVERSITY
    All positions available: Sales Representative, Accountant and Administrative Assistant. As part of our expansion program, our University is looking for part time work from home...
  • RUBY, ARIZONA CARETAKER
    S. Az ghost town seeking full-time caretaker. Contact [email protected] for details.
  • EXECUTIVE DIRECTOR
    Powder River Basin Resource Council, a progressive non-profit conservation organization based in Sheridan, Wyoming, seeks an Executive Director, preferably with grassroots organizing experience, excellent communication...
  • ADOBE HOME
    Passive solar adobe home in high desert of central New Mexico. Located on a 10,000 acre cattle ranch.
  • STEVE HARRIS, EXPERIENCED PUBLIC LANDS/ENVIRONMENTAL ATTORNEY
    Comment Letters - Admin Appeals - Federal & State Litigation - FOIA -