be developed and verified. The conventional approach that utilizes an average pressure spectrum budget is limited in its application to the marine mammal problem. A more comprehensive approach that encompasses contributions of both transient events and continuous sources to ocean noise should be pursued. Many of this committee’s recommendations, particularly those concerning information on distribution and source signatures of man-made sources, must be addressed in order to have the capability to develop a marine-mammal-relevant global ocean noise model. In addition, since model validation is a critical part of the model development process, the committee’s recommendations pertaining to the collection of high quality, well-documented ocean noise data sets must be pursued in tandem.
A program should be instituted to investigate carefully the causal mechanisms that may explain the traumas observed in beaked whales, whether this is a species-specific or broader issue, and how the acoustics of high-energy, mid-range sonars may directly or indirectly relate to mass stranding events. The research program outlined in Evans and England (2001) represents a good initial effort. The association of beaked whale mass strandings with high-energy, mid-range sonars has recently received much public attention, and the preliminary scientific findings of two such events have been released in agency reports but have not appeared in the peer-reviewed literature. Review of prior mass stranding reports for beaked whales further reinforces the probability of this relationship. In few cases have the beaked whale carcasses been in a condition to allow full, definitive forensic analyses. The complexity of obtaining appropriate samples from stranded beaked whales and the paucity of data to date, both from mass and nonmass strandings, prevent clearly determining the mechanisms and any causal relationship behind the traumas observed, the strandings per se, and sonar use.
The committee encourages the acoustical oceanography community, marine mammal biologists, marine bioacousticians, and other users of sound in the ocean, such as the military and oil industry, to make greater efforts to raise public awareness of fundamental acoustic concepts in marine biology and ocean science so that they are better able to understand the problems, the need for research, and the considerable potential for solving noise problems. The public, including environmental advocates, are very interested in anthropogenic noise in the ocean and its effect on marine animals. Recently there has been a communication gap between users of sound in the ocean, including scientists, and the public. Much of the gap in understanding between the ocean science community and the public arises from the public’s lack of understanding of fundamental acoustic concepts and the scientific community’s failure to communicate these concepts effectively. Source and received levels, propagation loss, air-water physical acoustic differences, and the term “decibel” are examples of concepts that have been misunderstood by the media, environmental organizations, and the general public.