Natural Resources Defense Council, Inc. v. Pritzker

The Natural Resources Defense Council (NRDC) (plaintiff) sued the National Marine Fisheries Service and certain federal officials (collectively, the agency) (defendants) to challenge the agency’s 2012 Final Rule authorizing the incidental take of marine mammals in connection with the Navy’s use of low-frequency sonar. The Marine Mammal Protection Act of 1972 (MMPA) prohibited the “take” of any marine mammals, including actions that might unintentionally injure such animals or disrupt their behavior. One exception for peacetime military-readiness exercises allowed for the take of a small number of marine mammals so long as mitigation measures would ensure the “least practicable adverse impact” on the species. The Navy planned to use low-frequency sonar to detect ships in and around U.S. waters. Because many marine mammals rely on underwater sounds to navigate and communicate, low-frequency sonar can physically injure or induce a stress response in marine mammals that significantly alters their behaviors. In the 2012 Final Rule, the Navy agreed to implement three mitigation measures to reduce the incidental take associated with its sonar program, including eliminating the use of low-frequency sonar within a certain distance of detected marine mammals and using lower-decibel sonar in coastal waters and certain offshore areas. The agency claimed it did not need to consider additional mitigation measures unless the best available scientific information established that those measures would be biologically important to a particular species. The district court granted summary judgment to the agency, and the NRDC appealed.