Doesn't farmed fish undo some of the advantages of eating fish? The big advantage of fishing over farmed meat is that we do not feed fish food grown on fields that could have fed people (which is a big part of the reason why meat is so economically inefficient). Fish just roam the seas and we scoop them out, with very little investment on our part.

Of course the fact that fish is such a relatively efficient source of food is also a good reason why we should take better care of the oceans. We can't eat fish if they die to our pollution. We also can't eat them if we hunt them to extinction. Sustainable fishing and cutting back on our pollution are vital to our food supply.

For anyone not aware yet, MSC is a certification for sustainable fishing and ASC for sustainable farmed fish. I eat no fish anymore that doesn't have either of those two certifications. But that does nothing to stop this kind of pollution.