White Sturgeon

The white sturgeon (Acipenser transmontanus) is the largest freshwater fish species in North America, capable of exceeding 6 meters in exceptional cases. A member of the ancient family Acipenseridae, it is native to large river systems along the Pacific coast, from the Sacramento River in California north through the Columbia and Fraser rivers into British Columbia. Some populations move between freshwater and brackish estuarine habitat, though many spend their entire lives in rivers and reservoirs. White sturgeon are extremely long-lived, with individuals documented living over a century, and several populations, including those blocked by dams on the Columbia and Kootenai rivers, are of significant conservation concern.

White sturgeon are recognized by their immense size and characteristic sturgeon features:

• Very large body size, often the biggest fish encountered in its range
• Five rows of bony scutes that become smoother and less pronounced with age
• Long, shovel-shaped snout with four barbels in front of a small sucking mouth
• Grayish to olive-brown coloration, paler than the greenish tone of green sturgeon
• Heterocercal, shark-like tail Its sheer size combined with a lighter body color and narrower barbel placement distinguishes it from the smaller, greener Pacific green sturgeon.

White sturgeon inhabit large, deep rivers, estuaries, and reservoirs along the Pacific coast of North America, from the Sacramento-San Joaquin system in California to the Fraser River in British Columbia. They favor deep pools and channels with sand or gravel substrate, and some coastal populations move seasonally into brackish estuaries to feed. Landlocked populations persist above hydroelectric dams in rivers such as the Columbia and Kootenai, where reproduction can be limited by altered flows and blocked migration routes. Water temperature and flow timing strongly influence when fish move between feeding and spawning areas each year.

White sturgeon are opportunistic bottom feeders, consuming invertebrates, fish, and fish eggs located with their sensitive barbels before being sucked up with a protrusible mouth. Migratory populations move between freshwater rivers and brackish estuaries to feed, while landlocked groups remain within reservoirs year-round. Spawning occurs in spring in fast-flowing river reaches with rocky or gravel bottoms, and females may not reproduce every year. Growth is slow and lifespan can exceed 100 years, making the species a keystone long-term inhabitant of the river systems it occupies.