Its cousin, the American paddlefish, is still around, though it's vulnerable.
Among other similar reasons (overfishing, pollution), dams are related to its decline: "Series of dams on rivers such as those constructed on the Missouri River have impounded large populations of American paddlefish, and blocked their upstream migration to spawning shoals.[29]"
But it's not too late...
https://en.wikipedia.org/wiki/American_paddlefish#Population...