California sea lions are doing just fine. Thanks for asking.
More than fine, actually.
The sea lions have fully rebounded with an estimated population of more than 250,000 in 2014, according to a recent study by scientists with the National Oceanic and Atmospheric Administration. In 1975, the population was estimated at less than 90,000.
The study reconstructed the population’s triumphs and trials over the past 40 years.
“The population has basically come into balance with its environment,” co-author Sharon Melin, a research biologist at the Alaska Fisheries Science Center, said in a statement. “The marine environment is always changing, and their population is at a point where it responds very quickly to changes in the environment.”
The rebound is a victory for the federal Marine Mammal Protection Act of 1972 that makes it illegal to kill or harass sea lions. But as in other instances of animal populations beating the odds — wolves, for example — it’s a success story that comes with challenges.
As the California sea lion population has grown, the animals have expanded their range, bringing them into conflict with humans and endangered fish.
In Astoria, male California sea lions have taken over an entire stretch of docks at the Port of Astoria’s East Mooring Basin. Port employees have attempted numerous deterrent tactics over the years, everything from fluttering wind dancers to a fake killer whale. Nothing has really worked.
Upward of 1,000 pinnipeds were recorded in a single daily count at the mooring basin in 2015. While fewer sea lions returned this spring, plenty showed up in the fall and many have stuck around through the winter instead of leaving like they have in the past, said Janice Burk, marina manager.
The Port plans to install more low railing fabricated by students from Knappa along the docks in the spring. It has proved to be the one deterrent that seems to work. Sometimes.
“When there’s large numbers of the animals out there, they kind of wiggle their way wherever,” Burk said.
Farther up the Columbia River, controversial management decisions have sought to curb sea lions hunting for salmon below Bonneville Dam. Oregon and Washington state fish and wildlife officials are authorized to kill problem sea lions to protect endangered species of salmon and steelhead at the dam and Congress is considering broadening that authority to the Willamette River and its tributaries.
So someone’s take on whether a robust sea lion population is a good thing or a bad thing “depends on where you sit,” said Chris Yates, assistant regional administrator for NOAA Fisheries.
The NOAA study will provide a baseline for understanding the population and will inform future management decisions, he said.
Researchers believe the sea lion population may have stopped growing. In recent years, it has actually declined slightly.
California sea lions are sensitive to environmental changes and the population experiences “abrupt, significant declines” in years associated with El Nino events, the study noted. There have also been declines in 2009, 2010, 2013 and 2014. Warmer ocean conditions can dramatically affect the food chain and can be difficult for sea lions to weather.
The study’s authors predict that if sea surface temperatures off the West Coast increase by 1 degree Celsius, it could halt the growth of the sea lion population. An increase to 2 degrees Celsius would lead to a 7 percent decline.
The sea lion population dropped between 2013 and 2014. It had reached a high in 2012 at around 306,220 animals. By 2014, that number dipped to just over 250,000.
Beginning in 2012, ocean conditions were particularly unfriendly for sea lions. A marine heat wave referred to as “the Blob” persisted off the West Coast and combined with an El Nino climate pattern. Thousands of malnourished sea lion pups stranded on beaches in Southern California.
“This is not just a story about continued growth of the population,” said Robert DeLong, a co-author of the study and leader of California Current Ecosystems program at the Alaska Fisheries Science Center. “These last several years have brought new environmental stresses to the California current, and we’ve seen that reflected by the sea lions.”
Ocean temperatures are expected to shift back toward normal, or even colder levels than normal this year, said Nate Mantua, a climatologist with NOAA’s Southwest Fisheries Science Center. “But we’ll have to wait and see.”
Because, he added, very little in the climate has been doing the expected for the last three years.