Military Sonar and Whales By: Joe Gasper

What is Sonar? Sonar is originally a acronym for sound navigation and ranging Sonar is used to detect other sea vessels, and to communicate between those vessels Also sonar is used for navigation

Two Types of Sonar Active Sonar Passive Sonar When sounds are emitted in pulses, and listing for echo's Passive Sonar Basically used for detecting noise made by other vessels

Active Sonar Active sonar can detect vessels that are to quiet to be picked up by passive sonar Active sonar is also used to detect marine mammals such as whales Also active sonar detects marine mammals in shipping lanes, or in high sound pressure zones. These high sound pressure zones are usually used for military exercise

Passive Sonar Passive sonar picks up sounds using electronic listening equipment. A target can be detected by the noise it makes from its machinery, the propeller, or the sound of the water passing around the vessel as it travels.

What Type Causes More Harm? The active sonar is what causes the problems for the whales It is usually beaked whales beached Beaked whales are mainly affected by the active sonar

Difference in Hertz Many military’s are now focusing on new types of sonar Military’s are testing and finding that low frequency sonar are not affecting, or stranding the beaked whales This may led to a compromise between the military and environmentalists trying to protect the whales

Hertz Measurements Low frequency sonar is different from mid frequency sonar Low frequency sonar puts out between 100 and 300 hertz, whereas mid frequency sonar puts out between 2,000 and 10,000 hertz

How Military Sonar Affects Whales Why are whales beaching themselves from the sonar? Researchers believe that the sonar causes decomposition sickness or “bends” This is common among scuba divers that rise to the surface to quick

Research Behind the Stranding In 2002 there were autopsies preformed on stranded beaked whales Four hours after a military sonar test started the beaked whales started to beach themselves

What Did the Autopsies Reveal? The researchers had eight beached specimen to examine When they were performing the autopsies they found two problems

Gas Bubbles in Blood Vessels

Hemorrhaged Vital Organs

References http://medinfo.psu.ac.th/pr/MedBoard/Img/20100216110043.jpg http://www.biology-blog.com http://www.whaleresearch.org http://news.nationalgeographic.com/news/2004/03/0331_040331_whalesincrisis.html http://onemoregeneration.org http://www.cascadiaresearch.org http://news.nationalgeographic.com/news/2003/10/1008_031008_whalebends.html http://misclab.umeoce.maine.edu http://www.surtass-lfa-eis.com