Thanks for the link.

In the linked article, I read:
It appears that "cat food" tuna is what's in question, as no one is sure what is really in it! Also, I read several times in the article that if you limit your cats tuna intake to 1x per week, or make sure it is getting a balanced diet, your concern should be pretty low.

Our cats have been eating human grade tuna (which is really Albacore) and so any mercury level is lower than in real tuna used for steaks, sushi and scraps for cat food (in Japan).

The general rule is the higher on the predator food chain (the more smaller fish it eats), the higher the mercury levels.

So, I think that if you make sure your cat is getting a balanced diet, the occasional tuna meal should be no cause for alarm.

Sam

 Read the following for advice. Plenty more found using Google feeding tuna to a cat .

 http://www.gorbzilla.com/all_about_tuna.htm