Sea lions in the Bering Sea are recovering thanks to conservation efforts

Wildlife protection measures can have long-lasting positive effects. For proof of that, look no further than threatened and endangered animal populations in the Bering Sea and the Gulf of Alaska.

By the end of the last century populations of Steller sea lions in U.S. waters had plummeted from well over 200,000 to just 50,000. In 1990 local sea lions were listed as endangered and thus protected under the Endangered Species Act in the United States. Several other species, including sea turtles, also came to be protected under the act in an effort to save them from going extinct.

Now, according to a study, thanks to stepped-up conservation under the provisions of the act local sea lions have been recovering with their numbers growing by around a quarter between 2003 and 2015. Encouragingly, sea turtles, too, have been rebounding in numbers.

“The U.S. Endangered Species Act (ESA) is a powerful environmental law protecting imperiled plants and animals, and a growing number of marine species have been protected under this law as extinction risk in the oceans has increased,” the study’s authors explain. “Marine mammals and sea turtles comprise 38% of the 163 ESA-listed marine ‘species,’ which includes subspecies and distinct population segments, yet analyses of recovery trends after listing are lacking,” they add.

The researchers set out to analyze population trends in all 62 marine mammal and sea turtle species listed under the ESA within the geographic boundaries of the Bering Sea and the western part of the Gulf of Alaska. They paid special attention to changes in local animal populations and the recovery status of 23 and 8 representative populations of 14 marine mammal and 5 sea turtle species, respectively.

“Using generalized linear and non-linear models, we found that 18 marine mammal (78%) and 6 sea turtle (75%) populations significantly increased after listing; 3 marine mammal (13%) and 2 sea turtle (25%) populations showed non-significant changes; while 2 marine mammal (9%), but no sea turtle populations declined after ESA protection,” they explain. “Overall, the 24 populations that increased in abundance were from species listed for 20 years or more (e.g., large whales, manatees, and sea turtles).”

The recovery in local animal populations has been due in large part to the Act, which was enacted in 1973 and, the scientists say, has “shielded more than 99.5% of the species under its care from extinction.” Without the ESA’s protection,” they note, “an estimated 227 species would have disappeared by 2006.”

In other words, conservation efforts, if conceived well and executed well, do work.