The National Fisheries Institute issued a warning to retailers that Greenpeace is poised to unveil another set of retailer rankings intended to grade U.S. grocery stores based on their seafood sustainability efforts.

Greenpeace had released it first such ranking in June, giving every grocery chain it rated a failing grade.

NFI called the repeat performance by Greenpeace a "divisive attempt at corporate blackmail as a success story that is impacting seafood sustainability." The trade group said that before releasing its seafood sustainability rankings in June, Greenpeace had demanded that retailers remove nearly 50 percent of commonly sold seafood from sale, or face a poor rating. Not a single operator then complied with the environmental group's demands. Greenpeace has also threatened U.S. grocery stores with "direct action" if they do not comply with its demands, NFI said.

NFI also said Greenpeace has tried to take credit for seafood sustainability efforts at grocers that it played no role in. For example, the organization has claimed to have influenced Ahold USA's seafood sustainability programs; but the senior seafood buyer for Ahold's Stop & Shop and Giant chains was quoted in IntraFish magazine as saying, "None of this is in reaction to the Greenpeace retailer rankings. These decisions were made as a result of the advice we received from the New England Aquarium."

For more information from NFI on the issue, visit www.AboutSeafood.com.