"We're still maintaining that balance out on the lake, making sure that we stock enough salmon to support the fishery but also stocking enough salmon to not crash or under-utilize the alewife population that's out on the lake," said Landwehr.
The process isn't just about raising fish. It's also for collecting data to track trends.
"They'll take all kinds of tissue samples and they're looking for signs of disease or various things that they'll notice over time," said Baumgartner. "They'll take all those samples back to their lab, analyze them and then they get back to us and let us know how healthy of a spawning population we have."
Once the DNR takes the eggs and studies the fish, their life cycle is over. But they don't go to waste.
Some fish are donated to local food pantries for people to eat, while others are made into fertilizer. Some eggs are even turned into bait.
The process makes sure these popular sport fish are always swimming in Lake Michigan.