Greenpeace announced it will send an open letter to retailers and foodservice companies nationwide this week urging them to pressure change among the three largest tuna companies.

"The big three major tuna brands, which control approximately 80 percent of the US market, don’t offer a single sustainable tuna product under their flagship brands," said Greenpeace US Oceans Director John Hocevar in the open letter.

His letter adds that many businesses have "urged Chicken of the Sea, Starkist, and Bumble Bee to clean up their act" and although there is recent progress in the tuna industry, this is not enough.

This