|
Noisy Ocean Cause for Concern |
|
|
|
|
Written by Jocelyn Cooper
|
The sea is like our very considerate neighbour, quiet and non-intrusive, while we are like a frat house; we throw garbage on its lawn and, more often than not, play our music too loudly. But unlike the neighbour, the sea can’t complain, and our “music” has gotten louder and louder, actually creating a new kind of ocean pollution—noise.
“The three major causes of underwater noise pollution are high-intensity military sonars, container ships and seismic air guns used to explore for oil under the ocean floor,” says Marsha L. Green, PhD, president of the Ocean Mammal Institute (OMI). “But the noise generated by the large number of recreational boats in the Northwest also has an impact on local whale populations, who depend on echolocation to survive. It’s harder for them to communicate and locate prey.”
According to the U.S. Navy, marine animals can safely experience underwater noise of levels up to 180 decibels, which is roughly the equivalent of 240 dB in air—twice the human pain threshold. But several sources, such as the OMI and the International Ocean Noise Coalition, say there is compelling evidence to the contrary; noise levels that high, while extremely disruptive to marine life, can also cause loss of hearing, internal injury and even death. In fact, in 2004, Fisheries and Oceans Canada found that snow crabs under seismic noise conditions showed bruised organs, bleeding, stress, abnormal ovaries, delayed embryo development and smaller larvae.
“The most intense noise, such as low-frequency active sonar [used by the U.S. Navy], literally kills whales and dolphins by causing bleeding around their brains and in their ears,” says Green.
“The evidence of sonar causation of whale beachings is
completely convincing.” —U.S. Navy-commissioned report, 2004
Even a 2004 U.S. Navy-commissioned report declared, “The evidence of sonar causation [of whale beachings] is, in our opinion, completely convincing.” However, due to the difficulty in studying ocean life, specifically mammals, in their natural environment, there hasn’t been enough research on the consequences of low-frequency sounds on marine life to determine if a direct cause-effect relationship exists. Nevertheless, scientists and organizations across the board feel there is sufficient cause for concern.
To help minimize the amount of noise we as recreational boaters produce on the water, it’s important to regularly clean the propeller, ensure the engine is insulated from the hull and keep up with the general maintenance, such as repairing bearings and loose plates. Also, try to buy products that are locally grown or manufactured whenever possible to help reduce the amount of goods being shipped across the oceans.
Learn more at the Ocean Mammal Institute website (www.oceanmammalinst.org) and the International Ocean Noise Coalition website (www.awionline.org/oceans/Noise/IONC). —JC
|
Front Page 
