Ive never thought to ask (usually only succumb to a chippy when im ratted anyway) but I wouldnt buy fish from a supermarket or fishmongers if it wasnt sustainable.Hmm interesting....youve just put me in the mood of fish now and im just starving not ratted :(
There are other options for sustainable fish if you don't fancy mackerel.
I have no objection to buying pollack, whiting or any of the other white fish alternatives.
I refuse to buy fish described described as 'white fish'. I want to know what I'm eating and will not pay cod prices for pollack.
We try and buy sustainable/fairtrade etc etc foods but some of the fish we've tried isn't that nice but we all like mackrel, and will try some of the other stuff that chippy has.
BTW they'd run out of mackrel so we had something else like a pollock and a rock between the four of us.
So the fish will be safe but your mam's carbon footprint will be bigger. (I have no idea about the whole carbon footprint thing but it seems to be that a trade off of some kind is being made here.)