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 would leave out any great white sharks that might wander into the Bay looking for harbor seals. (Like all sharks and rays, the great white’s skeleton is cartilage rather than bone.) Among the Bay’s bony fish, the white sturgeon (Acipenser transmontanus) takes the prize.

When Stafford Lake near Novato was drained for repairs in 1985, a seven-foot sturgeon was found that weighed 170 lbs and was 75 years old. Rumors of a giant fish lurking the depths of Stafford were rampant for years for once, a monster tale was true. But that fish was not so big by sturgeon standards. The West Coast record was taken long ago from the Frasier River 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 [[plant or animal?]]. They are also among the world’s longest-lived fish, sometimes living over 100 years. Not surprisingly, they reproduce late in life-females don’t spawn until age 18.

During their long lives, these fish can build up a high level of contaminants from polluted waters, so San Francisco Bay fishers should eat no more than two meals per month of sturgeon.

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

Michael Ellis – Ask the Naturalist – Bay Nature Magazine



Posted on

August 22, 2009