Harry Houdini would have been proud: Last November, within a matter of days, the horde of California sea lions that had converged on San Francisco Bay in record numbers during 2009—nearly 1,800 of them lounging along Pier 39 alone—vanished. Speculation about the sea lions’ whereabouts was rampant until word got out that Sea Lion Caves, a private preserve on the Oregon central coast near the town of Florence, reported the presence of much larger pods than usual.
Most California sea lions are not tagged, so there is no way to confirm that these newly arrived animals are the same ones that beat a hasty retreat from San Francisco Bay. But the sea lions’ rapid invasion of these Oregon waters has led marine scientists to suggest that the California animals joined other similarly motivated pinnipeds searching for colder waters and a better food supply.
Sea lions appeared to be on the move throughout 2009: Many marinas located on the Northern California coast also reported more sea lion sightings that year, although none approached the numbers that were hauling out in the Bay Area. “Their numbers definitely increased in 2009,” says Tim Morley, Santa Cruz Marina harbormaster. He points out that increased numbers can boost competition among the sea lions, and cause problems for humans, too. “Competition in the open water outside the harbor is pretty tough for sea lions,” he says. “The big males that get injured pull themselves up on the dock to recuperate. They are unpredictable and dangerous.”
The sea lions’ departure from San Francisco Bay leaves both bad and good news in its wake: Bad tidings for sea lion fans but a welcome reversal of fortune for beleaguered fishermen and boat owners who have long felt frustrated in their attempts to ward off marauding sea lions without running afoul of the law. At Pier 39, a popular tourist destination on San Francisco’s waterfront, the timing couldn’t have been worse: Thanksgiving is the official start of the Christmas shopping season, and the pier’s merchants were priming for the holiday traffic that the boisterous sea lions attract. “The sea lions are the number one draw at the pier,” says Pier 39 marina’s harbormistress, Sheila Chandor.
Chandor is in her 25th year of managing the pier and has been around long enough to remember when the sea lions first appeared, shortly after the Loma Prieta earthquake in 1989. “There was a male sea lion hanging around the dock—‘hauling out’ is the term we use. We nicknamed him ‘Flea Collar’ as he had a piece of wire around his neck,” Chandor recalls. “Two months after his arrival the sea lion population had grown to about five hundred, right after the height of the herring season here in the bay.”
Over the last twenty years, the pier’s sea lion population has ebbed and flowed, says Chandor, and managing the interests of both the pier’s official and non-official tenants has been tricky. The official residents—the merchants and the marina boat owners—have very different feelings about the pinniped crashers. Foot traffic to nearby shops and restaurants increased as the word got out that the sea lions were hauling out at the pier, and the merchants, happy to see an uptick in customers, started feeling protective about their new neighbors.
However, these warm feelings were not always shared by boat owners, who sometimes faced cantankerous male sea lions hauled out on the docks, blocking entrances to their slips. Owners sometimes needed a helping hand to remove the sea lions from their property—no small feat since these animals can grow up to eight feet long and weigh up to 882 pounds. It didn’t help public relations, says Chandor, that sea lions have smelly breath.
Pier management tried to deal with the influx. “We had to kind of think on our feet about this issue,” Chandor explains. “Over the years we rearranged where we berthed boats in order to minimize boat owners’ encounters with nosy (and noisy) sea lions.”
But when the pier’s sea lion population tripled in 2009, pier management had to revisit this containment strategy, Chandor explains. “We had six new floats, expressly dedicated to the lions, installed to accommodate their growing presence. We also added a ‘sea lion ambassador’ to our staff, to water down their floats and to use water hoses to keep the lions off of all other docks but K dock so that we can maintain property control.”
This kind of property control has left Hedley Prince, Fisherman’s Wharf harbormaster, frustrated. For Prince, the sea lions’ November disappearance is good news. Prince says that the sea lions have been a major headache for the fishermen who berth their commercial fishing vessels at the wharf, less than two miles away from Pier 39 on the same stretch of waterfront. The docks are not designed to hold the sea lions’ weight, he explains, their poop can create health issues, and the unpredictable lions may bite when they feel threatened.
“The most aggressive of the bunch, the male lions, tend to hang out here,” says Prince. He says that he has clearly labeled the entrances to the docks with warning messages about the temperamental nature of the lions, and that the entrances are controlled by locks, but Prince still is concerned about stray tourists who, excited to see a sea lion, may find a way to circumvent the locks and get hurt by the wild mammals.
The Marine Mammal Protection Act, or MMPA, limits the ways that frustrated fishermen and boat owners can chase away sea lions. Enacted in 1972, the law was meant to ensure that the populations of all marine mammal species are maintained at sustainable levels. It allows the culling—or killing—of sea lions in only very few circumstances. It also provides strict guidelines for how and when marina operators can legally deter sea lions from hauling out nearby—essentially when the sea lions damage private property, including fishing gear and catch.
Using high pressure water hoses to move the sea lions is the most common allowed procedure, although setting up barriers, such as netting and swim step protectors, and using visual repellants (like flashing lights or strobes) and noise makers (like firecrackers, horns, and bells) are also permissible techniques.
Many operators say that these legal methods are ineffective. “The Marine Mammal Protection Act severely limits how we can manage their presence. The lions don’t like to be sprayed with water, so that the best we can do, in order to comply with the act, is to spray them with hoses,” says Prince.
But the act has also been hailed for protecting marine animals and their habitat. Chandor says implementing the MMPA has had a beneficial effect on bay waters, and thus on the sea lion population. “The water quality has to be pretty good for the lions to stay around,” she says.
Amendments to the act are unlikely, says National Oceanic and Atmospheric Administration marine biologist Joe Cordaro, who monitors the status of marine mammal populations, working closely with operations that rescue stranded mammals. “There would be a tremendous outcry from the public if anyone suggested tweaking the act,” he says, “and no one in Congress would have the political will to do so.”
However, despite these strict environmental regulations, the Bay Area does pose two potential dangers that might discourage sea lions from living here: El Niño and harmful algal blooms. Cordaro says that El Niño, the periodic weather pattern in which normal trade winds subside, causing sea surface temperatures to rise, has been brewing in tropical parts of the world in 2009, yet has not made its presence felt here. Should it warm up California waters, the sea lions would need to dive deeper for colder water or make the trek northward to colder climes. “One- and two-year-old sea lions can’t dive that deep or swim that far,” he says. “With larger sea lion populations we could see an influx of starving sea lions that our present rescue operations could not support. They would be faced with making some very hard triage decisions about how many mammals they could save.”
Algal blooms present another danger, he says. Algae are a vital component of marine and freshwater ecosystems, providing the base for many marine food chains. But harmful algal blooms, called HABs, grow quickly and at very high densities, outcompeting, poisoning, or asphyxiating other organisms. Disastrous consequences can occur when fish eat a type of algal bloom called a toxic diatom bloom, says Cordaro. California sea lions can eat these tainted fish, and then die from brain lesions. Some toxic algal blooms have been sighted near the Sausalito-based Marine Mammal Center, and its fall/winter 2009 newsletter reported that half of the center’s rescued lions were being treated for some level of domoic acid poisoning.
Jim Oswald, the Marine Mammal Center’s communications manager, says that 2009 was a significant year for the health of the bay’s pinnipeds. “During May and June we saw an increase in malnourished pups stranding on the central coast,” he says. “This was a direct consequence of the subsiding trade winds that created a lack of upswelling.” Yet he is hesitant to make a direct link between the sea lions’ mass exodus from the bay and their recent Oregon presence. Sea lions are opportunistic, social creatures that don’t have dedicated turf, he explains, so it’s not unusual for them to migrate along the Pacific coast.
If they return, their former San Francisco neighbors wonder what will happen, especially if their numbers should continue to surge. Conventional wisdom says that sea lions will continue to haul out in San Francisco as long as the conditions are good, and Cordaro agrees that a plentiful supply of food in the bay coupled with the lack of sea lions’ main predators, great white sharks and orca whales, will continue to attract them. But, he points out, marinas like Fisherman’s Wharf are not designed to hold these hefty mammals, and property damage could become a bigger problem in the future.
For the time being, Pier 39 visitors will have to be content with spotting just an occasional sea lion, and Chandor and Prince will have some breathing room to examine their containment strategies. But when—and if—the sea lions return is anyone’s guess, since the big mammals aren’t sharing their travel plans. At least not in a tongue we understand.