I hunted Skagit Bay for over 20 years and for some reason, Canada geese were the very occasional large flock fly over. Even less frequent were the Canada geese that flew in range. Frequently, I would run into the ignorant hunter who shot at or even harvested brant calling them "Lesser Canadians". Sadly, these incidents generally happened on out of season brant and of course no brant card on the violators.
In short, don't count on Skagit Bay for legal dark geese.