National policy on the effects of underwater noise on marine mammals and turtles

Abstract

Marine anthropogenic noise is increasing at an unknown rate yet its effects on mammals and turtles are poorly documented. Such information is central to noise standards for marine animals required by two federal laws (MMPA and ESA). Good policy on underwater noise would set standards that are neither too liberal (thereby threatening the well being of marine animals), nor too conservative (thereby unnecessarily impairing essential human activities at sea). This balance must be found using existing data; standards cannot await new research. Policy must also lay out rules governing the introduction of novel underwater sound sources whose effects on animals are unknown. Should policy forbid such introductions until all possible consequences are known, or does a safe, incremental method of introduction exist? Should exceptions be made for novel sources associated with national defense? Policy must cope with sound sources that are outside the reach of U.S. federal regulations, such as international shipping. Finally, policy must frame the questions about underwater noise in a way that research can answer. Specifically, how much noise exists, how fast is it growing, where is it, and what consequences does it have for animals and their ecosystems?