Not only will it have mercury, but the "water" is actually a solution containing all sorts of things, including genetically modified soy. It says
"packed in spring water" on the main label, but if you read the ingredients, it will list more than just water. Most canned tuna is farmed, and the fish are fed a totally unnatural diet of wheat, soy, corn, fillers, and other things fish are not meant to consume. Color is added to the feed to give more color to the flesh of the fish. Your better option would be to buy wild caught fish, and to cook it and flake it up yourself. That way, you avoid alot of the unnatural garbage that is not listed.