It's the ocean. I went with a friend and enjoyed Witless Bay and the puffins. My friend was seasick the whole time. I didn't notice much of a chop - certainly not the kind of motion that would get to most people. Take a Gravol (Dramamine) before you go out if you're susceptible. I'd guess that if the sea is really rough the boats won't leave the port since it would be hard to look over the rail in rough water. The boat I was on also had a singer and some discussion of the local food specialties - both could induce a certain amount of nausea on dry land. I didn't see any Puffins when I went to Cape Breton so my advice is based on going to Newfoundland.