Navy sonar, cetaceans and the US Supreme Court: A review of cetacean mitigation and litigation in the US

► Several legal cases have been pursued in the US over concerns about the impacts of naval sonar during training exercises. ► Many of these cases expressed concerns that mitigation measures were not protecting whales – concerns often supported by the judiciary. ► One legal battle went to the US Supreme Court (Winter vs. Natural Resources Defense Council) but the effectiveness of mitigation was not addressed. ► This paper reviews these court cases and the additional mitigation measures proposed to protect whales. One source of anthropogenic noise in the oceans which has attracted much concern is naval sonar. As a result of possible impacts of such sonar, several environmental NGOs have pursued legal cases in the United States criticizing environmental assessments conducted prior to exercises and proposed mitigation measures. Cases have been brought using the US National Environmental Protection Act, Marine Mammal Protection Act, Endangered Species Act, Coastal Zone Management Act and other statutes. This paper reviews the chronology and results of these various cases. During the G.W. Bush presidential administration, the legal battle went to the US Supreme Court in the case Winter vs. Natural Resources Defense Council. This case however, did not address the potential impacts of sonar on cetaceans or the effectiveness of mitigation measures. During the Obama administration, mitigation measures for naval exercises have been revised, and working groups planned, in an attempt to resolve conflict between parties.