For the past three springs, Shilshole Bay Marina has been contending with droves of California visitors occupying their guest boater moorages––California sea lions that is. To Shelby Allman, Port of Seattle Harbor Operations Supervisor, it seemed like the furry visitors arrived almost overnight. By mid-May nearly 120 animals had hauled themselves onto five “finger” docks that are open to the public.
“They’re smelly, noisy, and potentially dangerous,” Allman said, “but they should be leaving soon.”
Overall, their presence in the region and even on marina docks is sign of a healthy sea lion population according to Scott Veirs, a marine scientist who chairs the Puget Sound Ecosystem Monitoring Program’s marine mammal work group.
Safety for both people and the sea lions has been the Marina’s priority. If provoked or threatened, the animals could bite.
“Being bitten by and adult sea lion is bad,” says Veirs. “It’s like being bitten by a bear…plus their mouth bacteria are really awful, like flesh-eating bacteria.”
Sound emitting devices were placed on the docks when they first arrived, according to Shelby, but the federally protected marine mammals were not deterred. Yellow caution tape is meant to remind humans to keep a safe distance but does nothing to keep the marine mammals corralled in one place. Marina staff periodically discourage the sea lions from lounging on the main walkway of the dock.
Sea lions are not uncommon to Puget Sound, especially in winter, when males venture north from California in search of food while females stay behind to feed and raise their pups in southern breeding areas. Veirs, who has been conducting weekly counts of the animals for the past two years, noted that small numbers begin arriving in fall and increase in mid-December. This year, peak numbers at their traditional haulout coincided with herring spawning in March. But about a month later, in late April, they began moving onto the marina’s guest docks.
“We’re getting to witness,” he says, “the success of a population of sea lions that reached carrying capacity on the outer coast and is pushing up to the north end of its range.”
The pinnipeds are looking for feasting opportunities that are worth swimming a distance for.
“The biggest bang for your buck is to gorge yourself on herring that’s stuffed with either eggs or sperm, right before they spawn. It’s sort of turducken of the sea where you have herring stuffed with eggs.”
Besides being formidable long-distance swimmers, Veirs says sea lions are amazing whisker predators. “If you blindfold them, they can still follow the path of the fish a couple minutes after the fish has swum by.”
Their whiskers allow them to sense subtle changes in turbulence in the water. “If it is more turbulent on the left side of your face than on the right, you can follow a turbulence trail and come up on the fish from behind. You don’t need light to be that kind of predator.”
While most of the Shilshole visitors are California sea lions (Zalophus californianus), Veirs has also identified Steller sea lions (Eumetopias jubatus) among the group—larger, stockier animals that are blonder in color and produce deeper, more guttural sounds than their California cousins. “Instead of barking, there’s this much more deep, almost terrifying, guttural growling going on,” he said. Sea lions are not new to Ballard either. At least as far back as 2021, a group of 40 to 50 temporarily occupied private docks next Ray’s Boathouse. Fencing and other physical deterrents encouraged the group to relocate to their historic haulout at the south end of the jetty that protects Shilshole Marina.
So why are they now occupying the guest docks?
Some speculate that the start of seasonal cruises that load near jetty prompted them to move to the more protected guest docks. But the real reason may be more dramatic. The story goes that the shift from jetty to guest docks was prompted by an event in 2023. In the wee hours of a windless night some of the live aboard residents at the south end of the marina were woken up by their boats rocking and the sound of killer whale calls echoing through their boat hulls. According to Facebook posts by residents that Veirs read, “Sea lions on the south end of the jetty were barking,” he said, “and there were signs the next morning that a killer whale had eaten at least one sea lion.”
Veirs’ hypothesis? That particular predation event was disturbing enough for them to seek out safer harbors to avoid becoming a meal for transient killer whales that are traveling through the Sound.
Regardless of the circumstances that brought them to the marina docks, the presence of the sea lions in Shilshole Marina represents an unlikely conservation success story. The Marine Mammal Protection Act of 1972 helped California sea lion populations recover from decades of culling programs in the early 20th century. Combined with recent record-setting herring runs in Central Puget Sound, the conditions have aligned to bring these marine visitors north to a presence in the Salish Sea and role in the marine ecosystem similar to what it likely was before settlers arrived.
Veirs continues monitoring the sea lions weekly, building a database that helps predict their movements and behavior. His research suggests this annual pattern may become the new normal as marine ecosystems continue to evolve. Marina guests and residents alike may have to share their space each spring, but by the end of June, the docks will return to their human visitors—at least until next year.
“Once they’ve discovered a haulout that’s useful to them,” Veirs notes, “they’ll remember it and may use it more and more over time.” Given their excellent memories for productive feeding areas, don’t be surprised if they return to Shilshole’s guest docks next year—hungry for another herring feast and perhaps even more comfortable calling Ballard home.
To report a dead, injured, or stranded marine mammal King or Snohomish County call Sno-King Marine Mammal Response (206) 695 – 2277; along the West Coast call: 1-866-767-6114. Visit the NOAA West Coast Marine Mammal Stranding Network for more information.