Nearly every store I go into, I check the fish counter.(The smell reminds me of my ex wife).
All the steelhead & salmon I've seen have adipose fins intact, and that leads me to think they're selling ranched fish. Maybe I'm incorrect, and they're all natives. If there were a few clipped fish, you could be certain they are netted.
If I was sure of the status, Id raise a little hell with the meat dep't manager.