Abstinence is not a good policy, but it's pretty much the best thing you can do personally unless you're somehow in charge of your country's fishing policy. By the way, as far as I know, fish farming is not much better.
The industry is looking into alternatives like insects, and typically 30-40% of the feed now comes from vegetable proteins and oils.
On the other hand, farmed Faroese salmon (just next door) has a much higher % of wild-caught fish in its feed, which contributes to the high omega 3 content of Faroese salmon.