By Dwane Wilkin Deep in an eddy of the Nechako River in central British Columbia, a courtship ritual older than the dinosaurs is about to take place. Moved to spawn by water signals, a white sturgeon female and her male suitors hover in the current momentarily, broadcasting and fertilizing in turn hundreds of thousands of eggs. To maximize the survival of their spawn, white sturgeon are supposed to reproduce in late spring, not autumn.
White sturgeon inhabit three large river systems, all on the western coast of North America.
A thriving commercial sturgeon fishery in British Columbia came very close to wiping out the species in the lower Fraser River 100 years ago, and overfishing elsewhere in the province has significantly imperiled stocks. White sturgeon in the Nechako, Kootenay and upper Columbia rivers all suffer from recruitment failure, meaning inadequate numbers of juvenile fish are being generated to replace current populations. Ralph Bahe, a member of the Kootenai Tribe of Idaho, monitored and assessed white sturgeon in the Kootenai River. Down and colleagues theorize that dams interfere with biological signals in the water that tell the sturgeon when to spawn. Dams built to restrain spring surge to prevent flooding and store up future hydro-electic potential effectively block these cues.