The MSC blue label appears on wild-caught seafood from fisheries that meet criteria on sustainable stock levels, minimised environmental impact and effective fisheries management. Chain-of-custody certification (MSC CoC) tracks the fish from boat to plate.
For farmed seafood the equivalent is the Aquaculture Stewardship Council (ASC). Some fisheries hold both certifications. MSC is the gold standard but has been challenged for certifying some fisheries with bycatch concerns — always check the species and gear type.