if it's for moral reason, i define these people as hypocrites. fish feel pain, and most fish (which are trawl caught) die in the most inhumane way of any 'food animal' on the planet (imagine the uproar if we drowned all our cows). Just because fish aren't 'cute' a lot of people assume that their deaths, like the deaths of insects, do not mean as much as the deaths of lambs and bunnies.
we actually eat lots of meat and not a lot of seafood because it's so hard to get sustainable fish we can afford. if you can't afford free range meat, that sucks, but the only thing suffering is the animal that died. trawl caught fish is awful for the fish, and also destroys the ocean floor and habitat for thousands of other animals.
rant over.