mcbem-2014-01-submission-wwf-en

activities are subject to the Act’s general authorization provisions, which are triggered “upon request”
by project proponents within specified geographic regions. As NMFS interprets this language, it is the
project proponent who decides the scope of authorization, and the proponent can group his activities
together or segment them into smaller units. Various user groups have taken advantage of the agency’s
liberality by dividing their activities into smaller segments, effectively avoiding cumulative impact review
under the statute. The Apache Alaska Corporation, in what is perhaps the most egregious of recent
examples, split a three- to five-year airgun exploration survey—taking place mostly within the critical
habitat of an endangered and declining beluga whale population—into a sequence of less legally
objectionable single-year surveys. Nonetheless, NMFS encourages user groups, particularly other federal
agencies such as the U.S. Navy and Bureau of Ocean Energy Management, to undertake programmatic
regional reviews and, over the next few years, is attempting itself to develop comprehensive, multisector
noise management policy.
For cumulative impacts, the much-desired holy grail is a comprehensive, quantitative model, such as the
Population Consequences of Acoustic Disturbance model originally proposed by a National Research
Council panel in 2005. That model begins with acoustic output and runs through a series of transfer
functions to effects on individual vital rates and, ultimately, to populations. The Office of Naval Research
has led a multi-year project to realize the model, using a handful of well-studied marine mammal
populations as the basis of its pilot studies; but producing an operative model is the work of decades, at
best. In the meantime, proxies are needed for adverse population-level impacts. For most U.S. cetacean
populations, as Taylor et al. (2007) observed, there is a high probability that even a precipitous
population decline (50% over fifteen years) would go undetected given present efforts; and the
literature (e.g., Goldhagen et al., 2013; Hatch et al., 2012; Miller et al., 2009; Moore and Barlow, 2013)
increasingly justifies concern that noise is negatively affecting marine mammals at the population or
species level.
Regulators and managers should establish conservative proxies for population impacts. Such proxies
may be based, for example, on the percentage of a population exposed to certain levels of noise, as was
the case of the Environmental Impact Report prepared on the Central Coastal California Seismic Imaging
Project (Wood et al., 2012). Or they may be based on existing baselines of exposure, on the assumption
that current levels of acoustic exposure are harmful and should be reduced over time. One leading
example of this approach is the 2008 Hamburg Statement, which called for a gradual reduction of global
ambient noise energy in the 10-300 Hz band relative to current levels (Wright ed., 2008). Additionally,
regulators and managers should require, over the life of major projects, monitoring with a significant
capacity to detect abundance trends in vulnerable populations.
(3) Evolve beyond the near field.—For most jurisdictions, the common denominator in noise mitigation is
the use of a “safety zone,” which requires powering or shutting down a powerful sound source if marine
mammals are detected within a short distance. The U.S. helped pioneer the safety zone in the 1980s and
1990s, initially in reducing injury risk from seismic airgun exploration in the Arctic and off the California
coast, then in addressing risk from naval training, pile driving, and other activities. Today the majority of
management energy is spent on designing protocols for safety zone maintenance and ramp-up. This is
true even though the impact radius around most powerful sources vastly exceeds the narrow band of
waterspace that safety zones and ramp-up are designed to protect (e.g., Fleishman and Streever, 2012).
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