EMERGING CONCERNS - Marine Pollution: What Everyone Needs to Know - page 135

of low frequency sound exposure by Andre and colleagues—
similar to what the giant squid would have experienced—in
four cephalopod species found that all of the exposed squid,
octopus, and cuttlefish had massive acoustic trauma in the
form of severe damage in their hearing organs.
Very loud, short, sounds, such as those produced during
pile driving, can harm nearby fish. Organs most sensitive are
those with gas/tissue interfaces (e.g., ears, swim bladders, air
sacs). Fish with swim bladders are particularly susceptible
to loud noises, such as from pile driving, because the gas in
their swim bladders is expanded by sound pressure, which
can cause the swim bladder to rupture. Other injuries include
disruption of cells and tissues, internal bleeding, and audi-
tory damage. However, more moderate underwater noises
of longer duration, such as those produced by vessels, could
potentially impact much larger areas and involve many more
animals. For example, the foraging habits of chromis, a coral
reef fish, were reduced due to boat noise, which also disrupted
normal orientation and movements in larvae of cardinalfish.
Playback of noise recorded from ships altered the feeding of
sticklebacks and minnows, which consumed less food and
showed startle responses.
There have not been many studies on effects of noise on
other marine animals, but the few studies suggest widespread
chronic effects. For example, crabs exposed to recordings of
ship noise showed an increased metabolic rate, indicating ele-
vated stress. Crabs also had reduced prey capture ability and
were less able to escape predators when subject to loud noise.
Effects were more severe on larger crabs than smaller ones.
What can be done about noise pollution?
While the use of sonar may be necessary in times of war, sonar
training should not be held in areas inhabited by cetaceans.
Training personnel about whale migration patterns would
reduce unnecessary harm to these animals. In March 2013,