White sturgeon spawn by broadcasting their eggs which become adhesive shortly after exposure to water.
Where successful spawning occurs in other river systems, these eggs attach to coarse substrate composed of gravel and larger-sized sediment.
While the sturgeon are documented to successfully spawn in the Critical Habitat reach, the exposed river substrate under most flow conditions is dominantly composed of fine sand with large migrating dunes.
Spawned eggs are presumed to settle onto the bed, become covered in the fine sand, or buried in the trough of migrating dunes resulting in suffocation. Interestingly, within a few kilometers upstream from the current (2005) spawning locations, the river is braided, relatively shallow, and has suitable substrate composed mostly of gravel and cobble.