Yoon S. Byun/Globe Staff

The topic of seafood sustainability has been under discussion so long it’s gone from buzzword to cliché. Here, cod at Area Four in Kendall Square.

Yoon S. Byun/Globe Staff

Chef Michael Leviton, of Lumiere in West Newton and Area Four in Cambridge, uses the definition of seafood sustainability from the UN.

Yoon S. Byun/Globe Staff

A hooked Chatham "Tenacious" cod with semolina crust, roasted pot vegetables, and salsa verde, from chef Michael Leviton.

Dina Rudick/Globe Staff

Fried smelts with meyer lemon and black olive vinaigrette from Rendezvous. Chef and owner Steve Johnson deals daily with the issue of seafood sustainability.

Essdras M Suarez/Globe Staff

Chef and owner of Island Creek Oyster restaurant at the Commonwealth Hotel, Jeremy Sewall, spoke to a crowd during a class called "Know your Fish."

Sheryl Julian/Globe Staff

Blue mussels are on the New England Aquarium's approved fish list. Recipe for mussels in white wine with saffron..