Researchers from the Technical University of Catalonia in Barcelona (Spain) exposed 87 individual cephalopods to short sweeps of low-intensity, low-frequency sound between 50-400 hertz and examined their statocysts (the fluid-filled balloon-like structures that help balance and position). The results confirmed that statocysts play a role in perceiving low-frequency sound in cephalopods. Immediately following exposure to low-frequency sound they showed hair cell damage within the statocysts. Over time, nerve fibres became swollen and large holes appeared. All exposed to the sound showed evidence of acoustic trauma, compared with unexposed individuals that showed no damage. With increasing offshore drilling, transportation, excavation and other activities, it is more likely these activities will overlap with migratory routes and areas frequented by marine life.