Some Buddhists do not walk without sweeping the ground before them, so as to avoid stepping on insects.
One eastern philosopher stated, "A gentleman should stat out of the kitchen," the thought being, it is not a good idea to see how an animal is butchered and prepared if you want to enjoy the meal in its final state.
Where you draw the line is entirely up to you. I only think that one should consider the question and be guided by their conscience.
Alternatively, next time you see roadkill, say to yourself, Hmm, I think I'd like to eat that. See if you can think it convincingly. Then when you go to dinner and the slab of dead animal is on your plate, you can think, "Hmm, this dead animal on my plate sure is appetiziing"
I have to eat. I do not have to kill in order to eat. A "well-managed fishery" is nothing more than controlled killing of animals that you KNOW are not required to be killed. Killing animals because they "taste great" really is no justification at all, and quite frankly, Jeffrey Dahmer could easily have justified killing people because they pleased his tummy.
Of course, in choosing between the life of an innocent cow and an innocent (or even not so innocent) person, I'd choose the person every time. And when choosing between the life of an innocent cow and the baked ziti, peanut butter and jelly sandwich, pasta salad, cous cous, rice and beans, hummus or whatever, I can confidently say, let the cow live, it isn't hurting anybody, and it isn't pleasant being slaughtered.
I would gladly chop down my own tree and grow my own vegetables. That's how I know its okay to kill trees and vegetables. So, I am not bothered by paying for someone else to do it for me. I would not gladly kill an animal, so for me, I know its wrong to have others kill them for me.
The business of meat is quite disgusting. If you won't eat a brain, kidney or liver, why would you eat the dead flesh of the animal? Its equally disgusting. But, if you are among the few who enjoy eating all manner of dead things, I doubt self-reflection will alter your views on things. And if the thought of eating brains and kidneys is not enough to gross you out, consider the fact that the the e-coli comes from the feces of the animal, and the reason you have to cook the meat so well is to avoid infecting yourself with bacteria-infested animal crap that is smeared all over the carcass in the slaughtering process.
Another reason why one should "do it yourself" when preparing a dead animal for consumption.
Any one of these reasons is enough to keep me from killing an animal.
By the way, in Finland, and I am sure other countries, they do indeed eat roadkill. If you run into a moose out there, and manage to survive it, the police or town locals will not let the animal go to waste.
Which reminds me... there are some folks who will only eat meat that dies a natural death. And in some villages near the Himalayas, I have heard it said that there are many a yak that have "fallen off the mountain" according to the street vendors selling the yak meat. Again, "what you don't know, often makes you feel better" and it is better to stay out of the kitchen, or in this case, to stay away from where the animal actually died, so you can believe it fell off the mountain!