This will certainly protect you.
Though it's pretty extreme to not eat one of the best eating fish around because of the miniscule risk of ciga..
Best bet ,IMHO,is to take smithy's advise to heart and find out where it is prevalent and avoid fish from those area's.
I have been eating them a couple of meals a week (out of the 3-4 times a week I eat fish) for several years without any complaint(generally in the 8-15kg bracket)so I think blokes like Garry (spaniard king)have been very unlucky to have been poisoned.Though it's no consolation for him as once would be enough.
We have also used some around the 18-20kg to feed to our local primary school for fundraising purposes on a couple of occasions and with no drama's at all.
I would personally be wary of specimens bigger than 20kg and also very large trout(though I have never caught one bigger than 5kg so it's not a worry)
scott