Effects of a Seismic Airgun Array on Juvenile Pallid Sturgeon (Scaphirhynchus albus) and Paddlefish (Polyodon spatula) in Lake Sakakawea, North Dakota

Seismic surveys are conducted by oil and gas companies to produce high quality images of subsurface geologic features and to increase the efficiency of direction drilling. Water-based seismic surveys regularly use airguns to produce the energy source. Airguns release a pressurize volume of air into the water producing a pulsed sound wave followed by a bubble pulse from oscillations of the bubble as it rises to the surface resulting from collapse and expansion of the air bubble. It is thought that with high peak levels and short rise times energy from airguns will have adversely affects on fish. This study evaluated the effects of sound pressure produced by a small four airgun array on pallid sturgeon and paddlefish. During this study the fish were placed in mesh cages, submerged and exposed to sound, monitored for 7 days post exposure and necropsied. Exposure to a single impulse SEL produced by the airgun array (224 dB_Peak [peak decibel level]; 205 dB_SEL) did not cause immediate or delayed mortality in either species within 7 days of exposure.