Drove to the Garrison Dam's fish hatchery and learned how they manage to harvest the eggs and milt, mix them to fertilize the eggs, incubate them, and raise the fry to fingerling and then to release size. It seems very difficult, complicated, and expensive for restocking fish for a few fishermen! But they were also raising pallid sturgeons, which are an endangered species, so I suppose that's a good thing to do.