White SturgeonAcipenser transmontanusWhere and when to see them

The white sturgeon is a giant, bottom-oriented fish native to the Pacific coast of North America. The Columbia River basin supports some of its most important populations. It is the largest freshwater fish native to North America, although some individuals also enter estuaries and coastal waters. Its ancestry stretches back to an ancient lineage of armored fishes. Dams, altered river flows, habitat degradation, and historical overharvesting have affected populations, with conditions varying substantially among river reaches.

Size

Adults commonly reach 1.5 to 3 m (5 to 10 ft); exceptionally large individuals can exceed 4 m (13 ft).

Weight

Highly variable with size; exceptionally large adults can exceed 400 kg (880 lb).

Lifespan

Can live for more than 100 years.

Status

Vulnerable (IUCN).

White sturgeon spend much of their time near the riverbed, searching for food with sensory barbels beneath the snout. They move between feeding, resting, and spawning areas as river conditions change. Some use estuaries and coastal waters, while others remain entirely in freshwater. In the Columbia basin, dams restrict movement and separate populations into different river reaches. Spawning generally occurs in spring or early summer, with timing influenced by water temperature and flow. Adults release eggs and sperm into flowing water, and the adhesive eggs attach to suitable bottom surfaces. White sturgeon mature slowly, do not necessarily spawn every year, and occasionally leap clear of the water for reasons that are not fully understood.

• Despite their size, white sturgeon have no teeth as adults.
• Their skeleton is largely cartilage rather than bone.
• Females generally mature later than males and can produce enormous numbers of eggs.
• Some Columbia River white sturgeon spend their entire lives in freshwater.

Wildlife opportunities depend on the river reach, water levels and species. River-specific viewing months have not been confirmed; general species seasons are not a local sighting forecast.

White sturgeon inhabit large rivers, deep channels, pools, reservoirs, and estuaries. In the Columbia River system, they occur both below Bonneville Dam and in impounded reaches farther upstream. Adults often use deep water and areas where currents concentrate food. Successful spawning requires suitable flows and relatively clean, coarse substrates such as gravel, cobble, or rock. Reservoir conditions and altered flow patterns can limit successful reproduction even where adult fish remain present.

White sturgeon feed on aquatic invertebrates and fish, with their diet changing as they grow. Young fish eat small bottom-dwelling organisms, including insect larvae and crustaceans. Larger individuals take fish such as lampreys, smelt, and other locally available species, and may also scavenge dead fish. They locate food using sensory organs and draw it into an extendable, toothless mouth.

Common name

White Sturgeon

Scientific name

Acipenser transmontanus

Animal group

Fish

Size

Adults commonly reach 1.5 to 3 m (5 to 10 ft); exceptionally large individuals can exceed 4 m (13 ft).

Weight

Highly variable with size; exceptionally large adults can exceed 400 kg (880 lb).

Lifespan

Can live for more than 100 years.

Status

Vulnerable (IUCN).

Identification

White sturgeon have a long, heavy body with five rows of bony plates called scutes rather than ordinary scales. Their back is usually gray to gray-brown, contrasting with a pale belly. Look for a broad, flattened snout, four barbels in front of an underslung mouth, and a sharklike tail with a longer upper lobe. Green sturgeon also occur in the lower Columbia, and distinguishing the two reliably may require close inspection rather than a brief surface sighting.