California sea lions have reached a high enough level that West Coast states could begin to take over management.
The National Marine Fisheries Service reports that the pinnipeds are at their “optimal sustainable population,” a triggering point in the federal Marine Mammal Protection Act.
Graphs produced by researchers at the federal Alaska and Southwest Fisheries Science Centers for the first-ever comprehensive assessment of the species show sea lion numbers are at their habitat’s carrying capacity, around 275,000 animals.
They first hit that benchmark around 2008, rising to 306,000 before The Blob took a bite out of their lunch, but then rebounded.
“The population has basically come into balance with its environment,” said Alaska-based research biologist Sharon Melin in a NMFS story announcing the news. “The marine environment is always changing, and their population is at a point where it responds very quickly to changes in the environment.”
Melin and her coauthors’ work was published today in the Journal of Wildlife Management.
The story notes that the tripling of sea lion numbers from fewer than 90,000 in 1975 has not come without consequences including chowing down on ESA-listed Chinook, steelhead and other stocks.
NMFS permits Northwest states to take out problem pinnipeds at Bonneville, and the story says that “the species maintained OSP levels even when small numbers of adult males were being removed to protect salmon runs in the Columbia River and climate events were depressing growth.”
To Melin, that means such removal programs are not all that likely to impact the species’ overall population, according to the story.
ODFW is currently asking NMFS for permits to remove sea lions from Willamette Falls, where they’re feasting on winter steelhead like their ancestor Herschel did at the Ballard Locks.