If you won't go to Seaworld due to animal welfare issues I do not recommend Marineland. It has a MUCH worse track record with regard to animal welfare than Seaworld. Seaworld at least has conservation programs and is working to educate/change with the times. Marineland is literally just a money-making venture. Recently some new legislation was passed here that makes it impossible for Marlineland to get anymore orcas which is nice so that should change up their model a bit I hope (this is actually a double-edged sword since they only have 1 orca now so she won't be able to have any companions which is sad).
It is basically a smaller, dingier, much more depressing Seaworld.
EDIT: to put this in perspective, I'm not opposed to properly funded zoos, aquariums etc. and I actually don't mind Seaworld as I find they do more help than harm but Marineland is basically a roadside zoo.
EDIT 2: I should probably add something to the actual topic lol
Does anyone in your family enjoy magic? The Greg Frewin Magic Show in Niagara Falls is quite entertaining. Very nice production values and the cost isn't too bad (there are usually groupons).
http://gregfrewintheatre.com/
In addition if you'd like something stereotypically Canadian I would recommend the Oh, Canada Eh? dinner show
http://www.ohcanadaeh.com/