Acoustic Response and Detection of Marine Mammals Using an Advanced Digital Acoustic Recording Tag(Rev 3)

Abstract

Abstract : Marine mammals are protected by three Acts of Congress: the Marine Mammal Protection Act of 1972 (MMPA), the Endangered Species Act of 1973 (ESA), and the National Environmental Protection Act (NEPA) of 1969. The MMPA prohibits any person or vessel subject to the jurisdiction of the United States to take a marine mammal where take is defined as to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal. Most of the large whale species were placed on the U.S. Endangered Species List in 1970, which has a similar prohibition on taking. The Department of Defense, as a branch of the Federal government, is required under NEPA to evaluate the potential environmental impacts of major actions or activities. The need for environmental compliance regarding marine mammals and anthropogenic sound creates a need to develop methods to assess the impacts on marine mammal populations. SERDP, the Office of Naval Research, and the environmental readiness branch of the Navy (CNO N45) have made major progress in the past decade on this issue. Major advances have been made in the detection and localization of marine mammal sounds, especially the low frequency calls of baleen whales (SERDP CS-48). We now know what levels of sound may start to cause effects on hearing in dolphins and seals (Ridgway et al. 1998; Kastak and Schusterman 1998; (Finneran et al. 2002; Nachtigall et al. 2003)). A major research effort defined the behavioral responses of four species of baleen whales to different received levels of the SURTASS LFA sonar (SERDP CS-1069). As CSSON-01-03 indicates, there is an urgent need for improved techniques to monitor toothed whales and their reactions to sound. Toothed whales are more common than the baleen whales and have hearing and vocalization ranges extending to considerably higher frequencies.