Sea lions encroaching on Sacramento waterways—and stirring up trouble

About a year ago, boat skipper Barry Canavero was fishing in the Sacramento-San Joaquin Delta with a deckhand and several customers. People pay veteran guides like Canavero a healthy fee to catch, and mostly release, striped bass, catfish and sturgeon. That morning, a client hooked a small striped bass and reeled the fish to the side of the boat, where the deckhand lifted it from the water to remove the hook. Then, the water exploded with spray, fur, teeth and claws. A bear-sized beast seized the fish, almost biting the man’s hand, and flopped back into the water with an orca-like splash and vanished.

That was the moment that Canavero lost his last shred of sympathy for the California sea lion. The big predators have always been eyed with disdain by ocean anglers, who regularly lose fish—especially salmon—to the animals. But in the past decade, California sea lions, whose numbers are booming, have become established residents of the Sacramento-San Joaquin Delta and, increasingly, even the river itself.

Canavero, who has guided sport anglers for almost 44 years, says sea lions upstream of San Francisco Bay are becoming more numerous and more aggressive every year.

“I was in Steamboat Slough the other day, and there were six sea lions,” Canavero said. “They’re there every single day, and there are always two or three more where the Sacramento splits into Cache Slough.”

Sacramento resident Mark Wilson, a 73-year-old retired fishing guide who has plied local waters all his life, says California sea lions first began showing up in the Sacramento Delta system about 15 years ago. Since then, he says, they have pushed farther and farther upriver. Wilson has seen sea lions chasing salmon in the Feather River, and three years ago he took a photo of a sea lion in the Delta tearing a 6-foot-long sturgeon to pieces.

Alan Fong, a recreational fisherman in Sacramento, says sea lions now routinely enter shallow, marshy areas, where they didn’t go just several years ago, to hunt striped bass during spawning events.

Dave Hurley, a fisherman and freelance outdoors writer, remembers fishing with his grandfather in the sloughs and backwaters of the Delta in the 1970s.

“My grandfather said the sea lions would never come into the river,” Hurley said. “Now they’re here.”

The population of California sea lions—different than but related to Steller sea lions and fur seals—has skyrocketed in the last few decades. There may have been as few as a thousand in the 1940s, following an era of aggressive hunting. The animals were killed for their pelts, while their meat was turned into pet food and their whiskers used as pipe cleaners.

Protections allowed the species to recover. It started crawling back, gained traction and, finally, exploded. By the 1970s, there were roughly 50,000 California sea lions along the California coast, according to Sharon Melin, a wildlife biologist with the National Oceanic and Atmospheric Administration. Today, she said, there are more than 300,000, and the population, it appears, may be pushing the marine habitat’s carrying capacity.

Not only are the sea lions encroaching into freshwater, but up and down the coast of California, newborn pups are starving. Almost 2,000 emaciated sea lion pups have struggled onto California beaches this winter. The animals, according to scientists, are abandoning their rookeries when their mothers spend longer than usual at sea hunting fish. The sea lions have inundated rescue centers, which saw similar events in 2014 and in 2013.

Adult sea lions are opportunistic feeders and can survive on a wide array of fish species, as their success in the Delta has shown. But when they are rearing babies, lactating mothers may need high-fat species like anchovies and sardines. Sardine numbers are currently at their lowest estimated level in decades, with the West Coast biomass calculated by scientists at 165,000 tons—down from 725,000 tons just two years ago. Anchovies, meanwhile, are said to be holding in deeper water than usual, possibly because of unusually warm surface temperatures.

“[The ongoing starvation event] is basically the environment and its resources checking the [sea lion] population growth,” Melin said.

While federal protections prohibit people from harassing or harming sea lions, the protected species has become as much a nuisance in places as raccoons or, more comparably, campground black bears.

In Berkeley, an aggressive sea lion became notorious for ambushing fishermen on the dock in the marina harbor in 2009. “It was basically mugging people for their fish,” said James Smith, captain of the California Dawn party boat.

Eventually, the sea lion attacked the boat’s cook. It bit her on the leg, and according to Smith, attempted to haul her off the dock into the water. Shortly thereafter, he said, it nearly bit a child. To his frustration, officials did not euthanize the animal. “If a dog or a mountain lion had attacked a person, they would have put it down in a second,” Smith said. “But no one wanted to touch a marine mammal that had attacked multiple people.”

That dilemma resolved itself, however, when the sea lion disappeared.

On Sunday, a 5-year-old boy was bitten in the face by a sea lion in La Jolla. In the Central Valley, there may not have been any sea lion attacks yet, but it seems only a matter of time before someone gets hurt. Wilson said he was almost bitten when a sea lion burst from the water beside his boat to snatch a striped bass from his hand. Wilson says a friend of his even had to resort to violence, whopping a sea lion on the nose with a billy club, after the animal leaped onto the rear of the boat. Hurley said an angler must reel madly to get a fish to the boat, as sea lions are very often furtively stalking nearby, sometimes unseen until appearing an arm’s length from the boat.

Ocean fishing-boat captains, ever at war with the marauding sea lions that stalk their nets and lines, used to fire guns at the animals. Such behavior certainly occurs today, but is generally shunned in the fishing community. While it is legal for some ocean fishermen to shoot sea lions with paint balls to protect their livelihoods, according to Smith, shooting at them with firearms draws the wrath of the law.

In 2010, a Sacramento man was sentenced to 30 days in jail for shooting a 650-pound sea lion in the face with a shotgun because, he told authorities, it had taken his fish. The animal was rehabbed at the cost of $51,000.

Hurley feels the sea lion population has ballooned out of control. He suspects the animals are having at least some negative effect on depressed Chinook salmon populations—especially at narrow pinch points where the migrating fish become easier to hunt.

“It’s definitely become a problem, but it’s one of those things no one wants to talk seriously about,” Hurley said. “It’s because they’re marine mammals and they’re totally protected.”