Yep Canvasback been to Delta several times in the '60's and '70's and hunted divers in lakes to the north including Dog, St. George, and St. Andrews. Also The Narrows and Oak Point on Lake Manitoba itself. I suppose carp have ruined both of those spots also. Greater Scaup used to be regular visitors at the latter. Minnesota DNR tried killing the rough fish and barring their entry into Lake Cristina, once one of the state's premier Canvasback lakes, but I have not heard much about the project for years.