White sturgeon

Natural History

The white sturgeon is like no other fish! Instead of scales, five rows of bony plates (scutes) reach from its gills to its tail, covering its sandpaperlike skin. It also has sharklike qualities including a cartilaginous skeleton and a sharklike tail.

Mostly a bottom-dweller, a white sturgeon spends its time rummaging on the seafloor for food. Unlike most other fishes, its taste buds are on the outside of its mouth. These taste buds, along with barbels (feelers) under the sturgeon's snout, help the fish select food, and a toothless mouth sucks it up.

Conservation

In the late 1800s, commercial fisheries began to supply the demand for caviar (sturgeon eggs) and smoked sturgeon. The fisheries grew rapidly—too rapidly. They collapsed in the late 1890s due to overfishing. In 1917, California banned commercial and sport fishing of white sturgeon.

Along with overfishing, habitat destruction—including dams that close off spawning grounds—and pollution contributed to the decrease in white sturgeon populations. Management of the fisheries is improving. As of 1997 in San Francisco Bay, the white sturgeon population is now larger than it has been since the 19th century.

Environmentally safe farms now raise white sturgeon for fillets and caviar.

Cool Facts

White sturgeon are the largest freshwater fish in North America. The largest on record weighed 1,500 pounds (628 kg).

The white sturgeon grows slowly, maturing in eight to 20 years, depending on location. Fish in the south of its range mature faster than those in the north. White sturgeon produce 100,000 to four million eggs per spawning, but they spawn only once every two to eight years.

In the past, isinglass—an almost pure gelatin prepared from the lining of sturgeon air bladders—was often used as a clarifying agent and as glue. In spite of modern substitutes for isinglass, it's still used to clarify white wines and for glue and sizing in art restoration work.