A few years ago I posted that I had the opportunity to jig for bottom fish with my brother in law, a few km outside of Port Hardy. Understand, neither of us were experienced with this type of fishing but he had a 40' sailboat, we were spreading my mother in law's ashes in the Pacific at her request, and it was a beautiful, sunny day. Some beers were on board and consumed. He knew my stand on salmon farms so I asked him to drift alongside a farm and we did, perhaps a hundred M from the first farm we came to (on the left, just out of Hardy Bay) jigging big ugly spoon like chunks of shiny metal, just off the bottom. Again, we are total beeks at this style of fishing but in about 45 minutes we caught 4 species of ground fish, the only 2 I could identify were a small ling cod and a capezon.
While drifting along side this salmon farm we saw many sea birds, a few dolphins, several sea lions and many seals. The place was alive with living things.
To me, this one day of fishing near a salmon farm totally convinced me a farm properly sited, taking into consideration sheltered bays and tidal influences, made my argument easier to defend.
There was a video posted earlier of prawns thriving beneath salmon farm net pens ..., perhaps someone could dredge that up