Effects of Underwater Noise Pollution on Marine Mammals

This is a portion of a power point presentation given by Dr. Marsha Green in June 2004 that addresses the impact of high intensity sonar, airguns and shipping on the marine environment. It also addresses International actions being taken concerning this issue.

1. Whales are acoustic animals - They use sound to:

2. Research shows that whales avoid sounds with a source level of about 120 dB (Richardson et al., 1995, Green et al., 1998)
There are sound sources in the ocean that produce noise levels much higher than 120 dB:

3. These very loud underwater sounds may cause various adverse effects on marine mammals including:

4. Public and scientific concern about underwater noise pollution has grown over the last decade after a series of mass mortalities of cetaceans associated with the use of mid-frequency active sonar in coastal areas.

The best documented cases, where stranded animals were recovered in time for necropsy occurred in:

5. Cuvier's and other beaked whale species suffered hemorrhaging in:

6. Other strandings correlated with the use of naval sonar occurred in:

However, the magnitude of the problem is not known since recent evidence indicates whales may die at sea where carcasses sink and are almost impossible to detect.

7. Are Current "Safe" Exposure Levels Really Safe?

8. High intensity sonar has been shown to have adverse impacts on other marine species as well.

9. The British Defense Research Agency reports that fish exposed to Low Frequency Active Sonar above 160 dB suffered:

10. Air Guns:

11. Shipping:

12. International Actions on Ocean Noise Pollution:

13. Petitions:


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