We humans are driving some ocean species to extinction, just as we did the passenger pigeon before commercial hunting was banned.
Factory farm chicken is hardly any better from certain ethical perspectives, but chickens are in no danger of extinction. Cheap canned tuna largely replaced canned chicken, thus the "Chicken of the Sea" brand.
http://www.seafoodwatch.org is a good source for people who still want to eat wild-caught fish that are not endangered.
Their tuna recommendations are here:
http://www.seafoodwatch.org/seafood-recommendations/groups/tuna
Many international fishing fleets are notorious for slavery, wage slavery, and very dangerous working conditions. Once you sign onto a fishing boat and it's out at sea there's no escape. The Mexican fishing industry is similar to the Hawaiian fishing industry which doesn't tend to pay non-U.S. citizens even minimum wage. But they won't work you to death and toss your body overboard, or drop you off at the nearest beach if you are injured or ill and unable to work. (North Korea is rumored to be the worst...)
My dad's an avid ocean fisherman. At one point he bought a boat just so he could fish, the proverbial hole in the water you pour money into. Our family's primary source of animal protein when I was a kid was fish my dad caught, and later fish me and my siblings caught with him. My dad's still an avid fisherman. Nevertheless I harbor no fondness for the commercial fishing industry. We should have left that industry behind in the twentieth century. There's simply too many people now and too much pressure on the oceans for commercially caught wild fish to be a common food source. (Much "farmed" seafood is a different environmental horror.)
I'm not a vegetarian like my wife or my daughter-in-law, but I am most days. And even if I was a vegetarian I'd still be a hypocrite if I insisted the same of others because I don't expect our dogs to be vegetarians.
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