While I have always been able to discern between Maine and Canadian lobster, the episode of Kitchen Nightmares and this thread actually made me question my discerning abilities. Since the argument seems to be unsolvable between those of us in the kitchen, I decided to use a "lifeline" and call a friend. I have a very good friend who is a marine biologist, so I invited he and his wife to my place for dinner on me and a discussion afterwards. First, THE answer....YES, there IS a difference between Maine and Canadian lobster, and it boils (no pun intended) down to the environments. Some of the comments on this thread make mention of the similarity of the Maine and Canadian waters, there is, however, very little temperature differences.....but the difference is in things like water current. To explain, my friend used a simple comparison between the lobster and people. There is a major difference in people who work out and those who do not, and so it is with every living thing on earth. Because the currents of the Canadian waters are much more active, the marine life is much more active...and in lobster, like people, they become more "muscular" so to speak...and like any other animal, more muscular means the meat is more developed....therefore more tough and stringy. Another major difference is in their intake...the food they eat, and we all hear "you are what you eat" and this is true. The food sources are different in the Maine waters than in Canadian waters...and I wouldn't think that needs explanation. SO, while many replies say they're the same, you may want to consult your local marine biologist!