Low-Frequency Sound and Marine Mammals: Current Knowledge and Research Needs Book

	List of Figures and Tables
	Executive Summary	1
1	A Review of Current Knowledge	8
	Changes in Ocean Sounds and Potential Effects on Marine Mammals	9
	Evaluating Noise Interference	12
	The Need for Additional Research	17
	Origins and Drawbacks of the "120-dB Criterion"	18
2	Regulatory Barriers and Possible Alternatives	25
	The Marine Mammal Protection Act and Its Interpretation	25
	Harassment of Marine Mammals	27
	Permitting Implications for Research Activity	29
	Magnitude of Potential Noise Pollution from Oceanic Acoustics Studies	33
	Proposed Changes in the Regulatory Structure	35
	Summary of Recommended Changes	38
3	Topics for Future Research	40
	Behavior of Marine Mammals in the Wild	41
	Structure and Function of the Auditory System	47
	Effects of Low-Frequency Sounds on the Food Chain	53
	Development and Application of Measurement Techniques	54
	App. A Comparison of Sound-Pressure Reference Levels in Air and Water	63
	App. B An Introduction to Marine Mammals	65
	App. C Comparison of Yearly Sound Energy from Oceanographic Research and Supertankers	74