I don't really watch HFW much, but have read a letter in the Daily Mail today which says (and this was in a HFW show last week) that he went fishing for grey mullet in a yacht harbour and duly caught one, which he cooked and ate.
Every marina in Europe is teeming with these fish, but no one ever tries to catch them. Apparently, a Spanish sailor told the writer of the letter about the diet of these fish and advised him not to eat them. Every yacht has a pump-out loo, but marina waters are always very clean - and the mullet are very big.
It doesn't bear thinking about does it?