A coalition of environmental groups plans to file suit today against the feds, seeking to overturn what they see as a weakening of labeling standards for “dolphin-safe” tuna. In April, the U.S. government expanded the number of fishing methods that qualify as dolphin-safe, including one called encirclement, a previously banned method that involves closing in on dolphins to get to the schools of yellowfin tuna that typically swim below them in the eastern Pacific Ocean. The enviro groups, including Defenders of Wildlife and Earth Island Institute, contend that the labeling changes were “arbitrary and capricious” and disregarded federal data on threats to dolphins.