Lake Winnebago lake sturgeon almost at the edge of extinction

A fantastic group of fish biologists in the Wisconsin Department of Natural Resources studied the centuries-long decline of sturgeon over a 20-year period and decided to do something about it: restore habitat, raise fry in hatcheries and release to a series of streams that feed into L. Michigan. The spawning sturgeon are coming back to the original streams after swimming long distances in the Great Lakes. The scientists are adept at this and developed imprinting techniques when they are about to be released. It's incredible -- see Sturgeon Underwater. Apparently, lake sturgeon are picky spawners. "In their spawning beds they like crushed limestone, stones of all sizes and coal cinders dumped by boats more than 100 years ago. They need depths of more than 15 feet and a swift current. It takes 15 years for males to reach sexual maturity and females won't lay eggs until they are 20 to 25 years old. The eggs can be a third of her weight so after spawning it takes two to seven years for the fish to spawn again." Sturgeon spawning is featured in "Mysteries of the Great Lakes" which is playing all around this summer.
-- posted by Barbara