For example:
> A recent study in British Columbia links the spread of parasitic sea lice from river salmon farms to wild pink salmon in the same river
The lice from the farmed fish devastate the wild salmon populations, so ecologically they are awful.
That to me is a pretty clear reason to avoid farmed salmon.
But you’re right, of course, if we should consider the environment as well. I haven’t eaten fish in 8 years, personally, partly because so much of it is fished or farmed in an unsustainable way.
For example:
> A recent study in British Columbia links the spread of parasitic sea lice from river salmon farms to wild pink salmon in the same river