White Sturgeon (Acipenser transmontanus)


A member of the Acipenseridae family of sturgeon, the white sturgeon is the largest fish occurring in freshwater in North America. In some areas, populations have recovered sufficiently since their decline in the early 1900s to support important recreational and commercial fisheries.

Other Names

sturgeon, Columbia sturgeon, Oregon sturgeon, Pacific sturgeon, Sacramento sturgeon; French: esturgeon blanc.

Identification

The white sturgeon has a moderately blunt snout as an adult, barbels closer to the snout tip than to the mouth, and no obvious scutes (bony, scalelike plates) behind the dorsal and the anal fins. The fish is gray to pale olive on its upper body and white to pale gray on its ventral side. It has 28 to 30 anal rays, 11 to 14 scutes on its back, and 38 to 48 scutes along the sides.

Size/Age

White sturgeon have been reported at more than 100 years old; most of the oldest individuals of the current era are roughly 40 to 60 years old. Accounts of historic landings of white sturgeon report maximum weights of between 1,300 and 2,000 pounds and a length of 20 feet. Fish under 6 feet long and weighing 60 to 70 pounds are commonly caught today, and fish from 6 to 9 feet long and weighing 200 to 500 pounds are possible.

Life history/Behavior

White sturgeon are anadromous, migrating from the ocean into freshwater to spawn. Spawning typically occurs from April through early July, when water temperatures are 50°to 64°F, during the highest daily flows of the river. Spawning occurs in swift water.

When hatched, yolk-sac larvae drift to deep water with slower currents where they grow rapidly, sometimes 15 inches or more in the first year. Females typically mature when 16 to 35 years of age, at roughly 47 inches in fork length.

Food and feeding habits

Adult white sturgeon are piscivorous and do feed in freshwater. Common baits include pile worms, ghost shrimp, grass shrimp, squawfish, and carp.

Distribution

White sturgeon are limited to the Pacific coast from the Aleutian Islands, Alaska, to Monterey Bay, California, although they move far inland to spawn. It is found in the Fraser River system; the Columbia River above Revelstoke, British Columbia; Duncan Lake, Vancouver Island; and possibly Okanagan Lake and other coastal drainages.

In Idaho, the white sturgeon occurs in the Snake River downstream from Shoshone Falls and in the Clearwater and the Salmon Rivers. It is landlocked in some drainages as well.

Habitat

White sturgeon primarily inhabit the estuaries and bays of large rivers and the deep pools of rivers when inland.
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