Steve - I agree there are paybacks from agricultural advances... like perhaps even the success of our species. As you already understand, my problem is with the methods and the lack of concern for the impact of what these businesses are doing.
On the range, the cows weren't escaping and diluting the buffalo's genetic integrity, and they weren't competing for their spawning habitat. We just rustled them slow dumb cows up and cooked 'em at the campfire if they got free. The combination of the inability to control the risks of what escapes into he sea / added to the seriousness of the impact created is where I draw the hard line. This is not to argue your points, indeed there are definite benefits and realistic needs generated by our success as a species on this beautiful blue orb in the cosmos we call Earth.
Since this industry is worth so much money, why do we not restrict the rearing operations to the now empty tank where we free'd Willy from for instance? I took my daughter to Newport Oregon to see Keiko face to face, and that tank could raise a truckload of salmon I tell you. Built in filtering, zero escapement, the works!
If these businesses want to play, they'll have to pay (I say). Just dumping nets in the sea doesn't cut it.
Not to come across as argumentative Steve (really) but I must make one comment on the wild vs. farmed fish comment. One of these days let's grill a wild ocean coho from the Northwest tip of the Olympic peninsula, splaked on a young alder "Y" branch, and slow smoke-broiled with no seasonings over green applewood sprigs on red embers by the wild pacific coastline. There ain't no amount of ferol bromide that activates my "savory" sensing tastebuds more than that. There is no red like the wild red meat of the real thing. Sure, salmon once in the river is not worth much after the spawning metamorphosis ensues. This is less true for males than females, and even less true of steelhead over salmon. The generation of those rich red yolk-filled eggs really drains the hens at spawning time. Every single dead dry salmon carcass was a red meated gourmet treat while still in the salt though. This thought used to make me kinda sad even though I was big into C&R; and in sterile glacial headwaters this is the main source of nutrients in the ecosystem.
Anyway, pleasure to discuss these issues, and there are clarly two sides of every debate. I hope we can do something to keep the historically rampant human exploitation syndrome out of this fragile balance.