Why we need to eat sustainably harvested fish
Some responsible grocers will have their seafood counters color-coded to help you make your decisions:
Green for well managed fish population, caught or farmed in ways that cause little harm to habitats or other wildlife.
Yellow for good alternative - be aware that there are concerns with how these are caught or farmed
Red - Avoid for now! - they are overfished or caught or farmed in ways that harm other marine life or the environment.
The Monterey Bay Aquarium Seafood Watch - provides you with all of this information with a Seafood Watch app or printable Consumer Guide from their website http://www.seafoodwatch.org/
Read how the recommendations are made.
Also you can access their Sushi Guide and National Guide as well as their West Coast Guide.