Acclimate them while it’s in your garage, sit in there with them for a bit. Then escalate to short rides, no fishing – just see how they react. once they acclimate to the actual ride, make some casts with some dummy weight or just a sinker in-case they decide to try and grab it on a backswing. Make sure they don’t think it’s fetch and they know to stay in the boat. Finally, catch a bluegill or perch and see what they do when it’s in the boat. My friend’s dog did great in the boat until a fish came on-board and then it went nuts – and that’s the worst time for the dog to go nuts. You don’t want a dog jumping around barking and nipping at big toothy fish while you’re trying to get it out of the net, unhooked, etc.
One more thing to consider, lots of things to get knocked over or knocked into the water (Beverages that might stain, tackle trays, phones, tools). And an unruly dog jumping around when it knocks over a tackle tray full of trebles is a recipe for disaster and can end your fishing day real quick.