I’d guess because Green Bay and Millacs are further south (closer to the equator)
Water temp is the variable
That being said there are some giants up there, and they have lots of food to eat

How’d it work out, do you still have these rods in your boat today?
and was it the spinning or casting triumph rod?

Thank you for posting this article
Ive been searching all over the internet for specific lake sturgeon fishing tactics. There is very little information out there, beside the obvious “fish on the bottom of a river or lake with heavy tackle”
This is the most informative piece I’ve found.

The lake has safe ice and has good water for an inner city lake. Just don’t fish in front of the colverts during spring melt or a heavy rain for safety.
The lake gets lets fishing pressure because its harder get there.
Good luck!