Bay Nature magazineOctober-December 2006


What is the largest species of fish you could find in San Francisco Bay?

October 1, 2006

Q: What is the largest species of fish you could find in San Francisco Bay?

A: Let’s limit ourselves to the true bony fish, which leaves out any great white sharks that might wander into the Bay looking for harbor seals. Among that group of fish, the white sturgeon (Acipenser transmontanus) takes the size prize. (Sharks and rays have skeletons of cartilage, not bone. Sturgeons’ skeletons, while mostly cartilage, do contain some bones, and the fish are classed with other bony fish.)

When Stafford Lake near Novato was drained for repairs in 1985, a seven-foot sturgeon was found that weighed 170 pounds and was 75 years old. Rumors of a giant fish lurking in the depths of Stafford were rampant for years and for once, a monster tale was true. But that fish was not so big by sturgeon standards. The West Coast record sturgeon was taken long ago in British Columbia—1,800 pounds and 20 feet long!

Sturgeon are the most primitive of the bony fishes, little changed from the age of dinosaurs. Instead of scales, they have overlapping bony plates called scutes. As adults, they are blind and toothless. With a specialized sucking tube and highly sensitive barbels (whiskers), they cruise along the bottom, feeding on anything remotely edible. They are also the Bay’s longest-lived fish, sometimes living over 100 years. Not surprisingly, they don’t reproduce quickly—females don’t spawn until age 18.

Though the estuary’s white sturgeon populations are on the rebound from massive overfishing in the 19th and 20th centuries, the smaller and rarer green sturgeon are now at the center of a controversy over federal protection. During their long lives, these fish can build up a high level of contaminants from polluted waters, so you should eat no more than two meals per month of sturgeon caught from the Bay.

Better yet, let those wonderful fish live out their long lives unhooked.

About the Author

Send your questions to Rosa-based naturalist Michael Ellis leads nature trips throughout the world with Footloose Forays (