White Sturgeon (Acipenser transmontanus)
Identification: Largest North American sturgeon with a maximum length of 20 feet. Head large and broad. Snout is short and bluntly rounded with 4 barbels between snout and mouth, closer to tip of snout than mouth. Mouth is ventral and toothless. Dorsal surface and upper sides dark to lighter grey, pale olive, or grey-brown, sometimes speckled with white. Lower surface pale grey to white, ventral surface all white.
Life History: Anadromous. Mature adults move into large rivers in the early spring. Spawning period usually occurs from May to June. Nests probably occur over rocky bottom in swift currents. Fecundity varies with size of the female, can be from 699,000 eggs per female to 3-4 million eggs per female. Adults survive spawning, and return to spawn more than once, but interval between spawning events increase.
Feeding: Mainly a bottom feeder, small individuals preying mostly on chironomids, also on mysids, molluscs, immature mayfly, caddisfly, stonefly, and copepods, and larger individuals preying mainly on fish and crayfish.
References:
Scott, W and Crossman, E. 1973. Freshwater Fishes of Canada. Fisheries Research Board of Canada. Bulletin 184. Ottawa, Ontario.
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