You have to be in the right spot on the bay. I've only shot on it a few times because I always had a little boat. You need to find weed beds and you will likely find carp in May/June. The water levels are really hurting right now and make everything a little more difficult. On the Saginaw rivet you would be better going upriver of Saginaw area. With all the boat traffic near the mouth visibility is about 2 inches and makes it hard to see fish.
I think I heard something about some strict Bowfishing regs for houghton lake do check with the DNR before you go out. I've never had problems with people along the populated places we shoot. Most ignore you, some are interested in what your doing and want to talk, and a couple get a little worked up. You just learn where those people are and avoid them. Then everyone stays happy. Good luck out there. Weather is starting to warm up a little.