Sea lions have made a magnificent comeback
Just a few decades ago, the California sea lion seemed on the verge of becoming an endangered species. It was 1964, and hunting and fishing had caused the breeding population off the West Coast to shrink to just 35,000.
How times have changed. After the Marine Mammal Protection Act of 1972 made it illegal to kill or harass sea lions, their ranks steadily grew — and grew, and grew. Now, according to recent estimates by the National Marine Fisheries Service, California sea lions number in the hundreds of thousands, making them comfortably within the range of what experts call the “optimal sustainable population.”
It’s as good a success story as a species can hope for. But there’s a hitch: A robust population of barking sea lions is not particularly easy for people to live with.
“The reality is that the people who wrote the Marine Mammal Protection Act could never have imagined the situation we have now,” said Sharon Melin, a wildlife biologist with the service and a co-author of the new sea lion status report. “Suddenly, they’re now in the system, and they’re competing with people for the same resources.”
Those resources include fish, but also seaside recreational areas. In December, a popular San Francisco swimming cove temporarily closed after three incidents involving sea lions that took a bite out of swimmers. The cove reopened in late December, and by early January, a fourth swimmer had been sent to the emergency room with a heavily bleeding bite.
Also, a group of residents, known as the Citizens for Odor Nuisance Abatement, sued the city of San Diego, arguing that a fence allowed sea lions and their stink to prosper, negatively affecting tourism and property values.
For what it’s worth, keeping sea lions around isn’t just good for sea lions. It could also be good for us.
The animals can fall victim to a nasty, sexually transmitted cancer that is associated with a herpes virus. Scientists think that studying this disease, which can melt a sea lion’s spinal column, may yield valuable insights into human cancers that are also associated with viruses.
“A lot of people that do research in cancer use lab animal models, and they control all the parameters as much as they can,” said Alissa Deming, a virologist who is the Geoffrey C. Hughes research fellow at the Marine Mammal Center in Sausalito, where researchers study cancer in stranded sea lions. “It’s not really reflective of how cancer develops in real life.”
Sea lions, on the other hand, are out in the real world looking for food, being exposed to pollutants, getting stressed out by predators, and just doing their thing — yes, often on beaches people consider theirs.