The blue logo printed on the packaging of the Filet-O-Fish and Fish Fingers items represents the company’s ongoing commitment to sustainable sourcing and certification of the chain's MSC Chain of Custody traceability standard.

McDonald’s U.K. has been using sustainably sourced fish in all of its fish products since 2001, said the MSC.

Last year, McDonald’s sold approximately 18 million Filet-O-Fish and eight million Fish Finger portions in the U.K. Both products use Hoki.