On a fine spring day alongside a Wisconsin river, several biologists wrestle a muscular, 120-pound fish onto her back and straddle her. The moves wouldn't be out of place in a rodeo. As the team restrains her, one member massages her swollen belly, working her eggs out of a release vent and into a plastic pail. The late-April scene occurs as, throughout the northern Midwest, water temperatures climb above 56°F (13°C) and lake sturgeon swim upstream to spawn. In several rivers, biologists such as these give Mother Nature an assist.
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