Environmental groups filed a lawsuit in a U.S. federal court on Wednesday, pressuring the U.S. government to sanction Mexico for failing to protect the critically endangered vaquita, the world’s smallest porpoise, according to court documents. The lawsuit seeks to pressure the U.S. government to sanction Mexico under a fisheries law called the "Pelly Amendment" to the Fishermen’s Protective Act, which authorizes the U.S. President to embargo imports of wildlife products, including fish, from another country.