Sea lamprey control in the Great Lakes has been a success.
Compared to the 1950s, 90% fewer of the toothy, invasive, eel-like parasite are spawning.
Control efforts have been so successful that some researchers now suggest a more permanent solution: complete eradication of the pest from the Great Lakes.
Great Lakes Now
https://www.greatlakesnow.org/2020/09/sea-lamprey-invasive-species-research-eradication-great-lakes/