Introduction to air guns and air-gun arrays

Abstract

The effect of seismic operations on marine mammals has been debated vigorously for years. Some feel that these operations could harm the animals. Others, based on anecdotal evidence of marine mammals swimming (or even playing) near active air-gun arrays, feel that harmful effects are unlikely. They claim that such evidence indicates, at the very least, that air guns do not physically damage the animals. Still others have relied on acoustic measurements to argue that any potential effect on the marine mammal population within a seismic survey area is negligible. Because of the importance of the discussion, the seismic industry has conducted numerous tests and monitoring studies to try to address this issue. To date, those studies have not identified any harmful long-term effects due to the proximity of marine mammals to air guns. Why then, does the debate continue?