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Resource
Management Issues:
Acoustic Impacts
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Overview
of the issue
A number of studies document impacts to living marine resources, including
behavioral changes and physical effects due to exposure to anthropogenic
noise and pressure waves in the marine environment. Anthropogenic sources
of noise include large commercial shipping traffic such as container ships,
freighters, barges and tankers, recreational and commercial boats, military
low frequency testing, research activities and aerial overflights.
Marine
mammals have been observed to deviate from their migration paths to avoid
noise, or interrupt their communications in response to elevated noise
levels. Certain anthropogenic noise is thought to mask sounds used for
mating, feeding and avoiding predators. Responses vary depending on the
acoustic frequency, decibel level, proximity to the source and other species-specific
sensitivity factors. Concern about the cumulative impacts of noise from
a variety of sources has grown as the ocean has become noisier in past
half-century. However, long-term cumulative impacts are uncertain and
range from minimal impacts in some situations to behavioral alterations
to possible physiological or physical damage to hearing, to stranding
events.
How is
the Sanctuary involved?
The Sanctuary has been involved in evaluating and requesting limits or
alterations of specific proposals to use acoustic devices in the region,
such as the Navys Low-Frequency Array proposal, but has not addressed
the overall issue of cumulative noise impacts. An assessment of the distribution
of deep-diving whales in the sanctuary has been compiled to assist
in evaluating potential impacts from acoustic disturbances
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