NOAA Fisheries Service is looking at how marine mammals react to underwater sound. Increasing evidence suggests that exposure to intense underwater sound in some settings may cause certain marine mammals to strand and ultimately die.
Cuvier's beaked whale. Strandings are associated with mid-frequency active military sonar, and most have involved beaked whales; the dominant species is Cuvier's beaked whale. (Credit: NOAA NMFS SWFSC PRD)
Some of these strandings are associated with mid-frequency active (MFA) military sonar, and most have involved beaked whales; the dominant species is Cuvier's beaked whale (Ziphius cavirostris), but the genus (Mesoplodon) has also been involved.
The coincidence between certain atypical mass strandings and active sonar exercises is convincing, but insufficient information is available to assess whether other signals pose a similar risk, and whether other species may also be at risk.
Until the causes of these strandings can be identified, and possibly dose- response relationships defined, it will remain difficult to discriminate an actual hazard from random coincidences of human activities and natural strandings.
A multi-phase field research project is underway to conduct Behavioral Response Studies of various underwater sounds to marine mammals (including beaked whales and other odontocetes).
The overall goal of the study is to understand the initial steps in the chain of events that lead from sound exposure to atypical mass strandings of beaked whales; and to use that understanding to identify a safe response that can be used to indicate risk.