You can eat flake no probs, just so long as you have not had any other high mercury fish. The problem with Shark (flake) comes from when sharks are dying, they release mercury into their blood as a final up yours to whatever is killing it, and presumably, eating it. If the fish isn't bled immediately after it is killed, the mercury toxifies the flesh of the fish and you cannot eat it.
This is not usually an issue at all with commercial fisherman, as they bleed the sharks immediately they are caught.


You can eat everything from the fish n chip shop, even flake , but you may want to steer clear of things like pre-fried chikko rolls, or shellfish.