By Ariana Acosta and Maggie Chen
As a Bay Area resident, you probably don’t need me to tell you that sea lions are special members of our beautiful scenery. But you might have done a double take a few months ago when you saw one that looked less like a California sea lion and more like a small submarine.
“Chonkers” was an approximately 2,000-pound Steller sea lion, which is far larger than the California sea lions people normally associate with Pier 39 in the San Francisco Bay.
The Steller sea lion is the largest member of the “eared seals” family and males can reach approximately 2,500 pounds and 11 feet. Stellers are much larger than California sea lions and are generally lighter/blonder in coloration. The Bay is considerably farther south of where they are most commonly encountered, making a Steller sighting here unusual.
So what was a giant northern sea lion doing hanging out with the regulars at Pier 39?
Steller sea lions are highly mobile marine predators that travel and forage over large areas in search of prey. Their diet varies in different parts of their range and times of the year but Steller sea lions likely depend on readily available and predictable prey. The Bay and surrounding coastal waters can provide abundant food, but Chonkers’ unexpected visit also gives us a chance to think about how connected our local waters really are.
A watershed doesn’t end where the creek meets the Bay:
We tend to think of wildlife as belonging to particular places. But the Bay is connected to the Pacific Ocean, and animals don’t recognize our human boundaries. Our local creeks, storm drains, shorelines, marshes, and the Bay are all part of the same interconnected system.
That connection works both ways. What happens upstream can eventually affect downstream coastal ecosystems and something as ordinary as a piece of trash on a neighborhood street can eventually become marine debris.
Marine debris isn’t just an eyesore. It can become an ecological problem for wildlife through entanglement, ingestion, and habitat degradation. Steller sea lions are among the species NOAA identifies as vulnerable to threats including contaminants, entanglement, disturbance, and changes in prey availability.
So what can we do to protect marine mammals like these?
You don’t have to travel to Alaska to help protect Steller sea lions. You don’t even have to get on a boat. When volunteers pick up trash along the Contra Costa shoreline, they’re acting at a crucial point in a much larger connected system. Every piece of litter removed is one less piece that can be carried by wind, stormwater, creeks, or tides. And importantly, Coastal Cleanup Day (Join us on Sept. 19!) isn’t just about picking things up; we also collect data about what we find, which helps identify patterns and inform broader solutions. Our cleanup work doubles as both stewardship and community science.
In the first week of September, another massive Stellar sea lion has entered Pier 39 which staff informally named “Beefy Buddy.” The newcomer made an appearance for the first time and left the next day to continue on their journey. In 2026, there has been more massive marine mammal visits than the years prior. With the increasing visits and new sightings, we are reminded of the interconnectedness of upstream and downstream and of how every living thing is connected to each other.
We may never know exactly why one particular animal decides to travel this far south.
But Chonkers’ visit is a reminder that our local shoreline is part of something much larger. The wildlife of the Bay is connected to our neighborhoods and our actions are connected to theirs, so let’s help a neighbor out and keep our shared backyard clean and healthy.
Join us this Saturday, Sept. 19th from 9AM-12PM,, at one of our Coastal Clean Up Day events!
📍Shimada Friendship Park, Richmond
📍Wildcat Creek, Meet at Lucky A’s North Richmond Baseball Field, Richmond
References
Vaziri, Aidin. “Chonkers look-alike visits San Francisco’s Pier 39, then disappears.” San Francisco Chronicle. 4 September 2026. Retrieved from https://www.msn.com/en-us/travel/parks/chonkers-look-alike-visits-san-francisco-s-pier-39-then-disappears/ar-AA2bAXYY?ocid=BingNewsSerp
NOAA Fisheries. Steller Sea Lion. Species Directory, 2026. Retrieved from https://www.fisheries.noaa.gov/species/steller-sea-lion
Paul, Andrew. “Chonkers the 2,000-pound sea lion is making waves in San Francisco Bay.” Popular Science. Endangered Species, Wildlife. 27 April 2026. Retrieved from https://www.popsci.com/environment/chonkers-giant-sea-lion-san-francisco/
