A young parishioner carries plates filled with fried fish and potatoes to a table during a Lenten Friday fish fry at St. Frances Cabrini Catholic Church in Littleton, Colo., in 2009. David Zalubowski/AP hide caption

itoggle caption David Zalubowski/AP

Escolar, right, is often substituted for more expensive Albacore tuna (left), a report on mislabeled seafood found. Yoon S. Byun/Boston Globe via Getty Images hide caption

itoggle caption Yoon S. Byun/Boston Globe via Getty Images

Swordfish from Canada are marked with a label from the Marine Stewardship Council at a Whole Foods in Washington, D.C. The MSC says its label means the fish were caught by a sustainable fishery, but critics says it's not always so clear. Margot Williams/NPR hide caption

itoggle caption Margot Williams/NPR