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The Science Behind the Decision <br />Answers to Frequently Asked Questions about the Atlantic Geological and <br />Geophysical Activities Programmatic Environmental Impact Statement (PSIS) <br />Will air guns used in seismic surveys kill dolphins, whales and sea turtles and ruin <br />coastal communities? <br />To date, there has been no documented <br />scientific evidence of noise from air guns <br />used in geological and geophysical (G&G) <br />seismic activities adversely affecting <br />marine animal populations or coastal <br />communities This technology has been <br />used for more than 30 years around the <br />world It is still used in U S waters off of <br />the Gulf of Mexico with no known <br />detrimental impact to marine animal <br />populations or to commercial fishing <br />While there is no documented case of a <br />marine mammal or sea turtle being killed Bottlenose dolphin from the Atlantic AMAPPS study <br />by the sound from an air gun, it is possible <br />that at some point where an air gun has been used, an animal could have been injured by <br />getting too close Make no mistake, airguns are powerful, and protections need to be in place <br />to prevent harm That is why mitigation measures -- like required distance between surveys <br />and marine mammals and time and area closures for certain species -- are so critical <br />Is it true that the air guns are 100,000 times louder than a jet, and if so, won't they kill or <br />deafen marine life? <br />A large air gun is loud, although it is not 100,000 times louder than a jet. Measured <br />comparably in decibels, an air gun is about as loud as one jet taking off Scientists who <br />specialize in acoustics confirm that sounds in water and sounds in air that have the same <br />pressures have very different intensities (which is a measure of energy produced by the <br />source) because the density of water is much greater than the density of air, and because the <br />speed of sound in water is much greater than the speed of sound in air. For the same <br />pressure, the higher density and higher speed make sound in water less intense than sound in <br />air. <br />We do not know what a whale, dolphin, or turtle actually experiences when it hears an air <br />gun. Many marine mammal species -- but not the baleen whales including North Atlantic right <br />whales -- have reduced sensitivity to sound signals that are in the same frequency range as <br />airplanes and air gun arrays. Some whales appear to move away from surveys, indicating that <br />they probably don't like the noise, but bottlenose dolphins have often been observed <br />swimming toward surveying vessels, and ride bow waves along the vessels <br />Is it true that the government's own scientists expect 100,000 injuries or deaths of <br />marine life if seismic surveys go forward? <br />This statement misrepresents the facts. When our scientists began to look at possible impacts <br />of seismic surveys, they first looked at what might happen if no measures were taken to <br />mitigate or avoid possible injury to marine mammals Next they began to look at what could be <br />212 <br />