Sound is as important to whales as vision is to us. Sound travels farther in the ocean than light does — so whales grunt, call or sing, or listen intently, and their lives depend on sending and receiving these acoustic cues reliably. They’re quite good at it. Whales and their prey have evolved these acoustic systems over millennia. The problem is that in the last hundred years or so, we have started competing with whales for acoustic space by using ships and conducting other activities that create a lot of underwater noise (mostly unintentionally). So trying to communicate through underwater noise is a little like having a great cell phone that relies on a terrible network provider. Unfortunately for whales and other marine life, the consequences of a “dropped call” are more serious than they are for us. If human activities jam whale acoustic signals, the information lost is not trivial. We suspect that the acoustic information being transmitted is of the kind: “There is a predator just around the corner.” Or, “Eat this fish. It may be the last one you see for days.”
The cornerstone of our acoustics project uses pop-ups, developed by Cornell University’s Bioacoustics Research Program. These autonomous machines sit on the seabed, recording anything that swims or sails by until they are told to come to the surface. We have been using these machines since 2008 along the continental shelf waters of British Columbia, Canada. With a lot of help from mariners throughout BC, we’ve successfully deployed and retrieved 12 of these fancy rigs in sometimes terrible weather. We now have thousands of hours of recordings of ambient sounds that include whale and dolphin calls. Our future plans include a study to extract these calls to help us identify important habitats within BC for different marine mammal species. But for now, our primary interest is in the shipping noise data on the recordings. Working with Chris Clark at Cornell, we are modelling how much acoustic space the whales lose from different levels of shipping noise.
In conjunction with this study, Rob has recently won a Marie Curie Research Fellowship and is now Principal Investigator on the EU FP7-funded project CONCEAL (Chronic Ocean Noise: Cetacean Ecology and Acoustic habitat Loss) to investigate the effects of acoustic masking on whales. This study builds on Rob’s 2009-10 Canada-US Fulbright Visiting Research Chair position at the University of Washington to compare Canadian and US policies to protect whales from human-caused noise. Project CONCEAL builds linkages between biologists and statisticians at University of St Andrews to model population-level consequences of the acoustic masking work that Rob and his colleagues at Cornell are demonstrating.
