Yeah, that's WAY too much. Especially if it's canned tuna. They kind of exaggerate the levels, but how much you are eating is WAY to high..
Simply put the small cans of tuna is 6 oz....So if you are eating 3 cans a day that would be 18 oz per day of canned tuna. And in a week that would be 126 oz of canned tuna.
There is a mercury calculator at
www.gotmercury.org and just estimating I put your weight at 200 lbs and 126 oz of canned albacore a week and you were like 20x Times over the normal limit. And that is not even including the salmon you are eating.....I'd try to sub some of those fish meals out with chicken breast.