Skip to main content

Currently Skimming:

1 Introduction
Pages 13-22

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 13...
... Because of the low loss characteristic of sound transmission compared with light transmission, the use of sound had developed evolutionarily as the predominant long-range sensory modality for marine mammals. As engineers and scientists learned to appreciate the properties of acoustic propagation in the sea, they introduced sound sources to communicate and to detect objects in the oceans or on or below the seafloor.
From page 14...
... . Although there are many documented, clearly discernible responses of marine mammals to anthropogenic sound, responses are typically subtle, consisting of shorter surfacings, shorter dives, fewer blows per surfacing, longer intervals between blows, ceasing or increasing vocalizations, shortening or lengthening vocalizations, and changing frequency or intensity of vocalizations.
From page 15...
... HISTORY OF NATIONAL RESEARCH COUNCIL REPORTS The National Research Council has produced three reports on the effects of noise on marine mammals, in 1994, 2000, and 2003. The primary goal of the first, Low-Frequency Sound and Marine Mammals: Current Knowledge and Research Needs, was to address the specific issues raised by the Heard Island Feasibility Test, which sought to "establish the limits of usable, long-range acoustic transmissions" (Munk et al., 1994)
From page 16...
... Agencies were encouraged to regulate within the context of total human impacts on marine mammals -- including fisheries, shipping, the oil and gas industry, and research activities -- and to expend their primary effort on activities with the greatest potential for harm. The 2000 National Research Council report, Marine Mammals and Low-frequency Sound: Progress Since 1994, noted that the 1994 amendments to the MMPA addressed some of the issues raised in the 1994 report.
From page 17...
... The report offered a number of recommendations; the overarching one was the need to understand better the characteristics of ocean noise, particularly from human-made noise, and its potential effects on marine life, especially effects that may have population consequences. Thus, each of the three previous National Research Council reports has recommended research to resolve critical uncertainties about the effects of noise on marine mammals.
From page 18...
... There has been little progress on those programmatic recommendations, and the present committee reemphasizes that progress in critical research requires that the federal government develop and fund a dedicated multidisciplinary research program on the subjects in question. CALL FOR A NEW NATIONAL RESEARCH COUNCIL STUDY The recommendations of the 2000 National Research Council report have received great attention and been applied by regulators, legislators, and permit applicants to describe level B harassment under the MMPA.
From page 19...
... On reflection, it became clear that animals in the wild rarely spend substantial amounts of time engaging in activities that are not biologically significant. Even seemingly frivolous BOX 1-1 Statement of Task In its 2000 report, Marine Mammals and Low-frequency Sound, the National Research Council recommended that the Marine Mam mal Protection Act definition of "Level B harassment should be lim ited to meaningful disruption of biologically significant activities that could affect demographically important variables such as reproduc tion and longevity." Recognizing that the term "biologically signifi cant" is increasingly used in resource management and conserva tion plans, this study will further describe the scientific basis of the term in the context of marine mammal conservation and manage ment related to ocean noise.
From page 20...
... FINDING: As opposed to the definition of biologically significant activities, whose disruption can constitute harassment, the crucial determination is of when behavioral or physiological responses result in deleterious effects on the individual animals and the population. The statement of task incorporates two issues that had been concerns of earlier National Research Council reports.
From page 21...
... The participants in the workshop made it clear that current empirical data and theoretical knowledge are insufficient to accomplish all the goals of the committee. Therefore, this report offers recommendations intended to provide a roadmap for the development of a predictive model of the effects of ocean noise on marine mammal populations and presents suggestions for temporary measures for regulating the effects until a predictive model is developed and tested.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.