A new study looking at the effects of excessive underwater noise on whales, dolphins and porpoises has revealed that they can often face a choice of living over eating when they hear a threat.
Researchers, including scientists from the University of St Andrews, have discovered that man-made underwater noise pollution is picked up by whales in a similar manner to the way they sense natural predators, explaining why some species are particularly sensitive to noise disturbance.
The findings reveal that whale, dolphin and porpoise responses to sounds such as military sonar systems are shaped by how they evolved to respond to natural predators like orcas, and that underwater noise disturbance created by humans is causing them to stop foraging for food and, therefore, become weakened and more vulnerable.
The research team found that navy sonar caused cessation of foraging in all four species of whale they studied – northern bottlenose, humpback, sperm and long-finned pilot whales – which all rely on acoustic signals to assess risk from attack as well as to find food themselves.
'Behavioral responses to predatory sounds predict sensitivity of cetaceans to anthropogenic noise within a soundscape of fear' by Patrick Miller and Saana Isojunno, is published in the journal PNAS and available online.