Think about it, you are at a party and trying to talk to someone in your group and you’re having to raise your voice as the music gets louder and the party gets more raucous. Soon you are struggling to hear and trying to lip read, conventional communication breaks down. Now imagine that happening nearly everyday of your life…no not the partying…the inability to be able to communicate using your voice. What if you were in different rooms to your friends or family then you couldn’t even use sign language…This is what is happening to many marine mammals the world over.
First a little background interlude:
The ocean is inherently noisy, from crashing waves to cracking ice, however due to an increased human presence on the ocean over the last fifty years the amount of anthropogenic noise pollution has significantly increased and in some places surpassed that of natural sources. This anthropogenic noise comes from shipping traffic (transporting produce, cargo and natural resources) and also noise that is a result of ocean exploration such as seismic activity and sonar. This noise pollution has become so prevalent and increased over such a short time that the International Maritime Organisation added commercial shipping noise and its impacts on marine life to its Marne Environment Protection Committee work programme back in 2008.
Now back to marine mammals:
Many cetaceans (whales, dolphins and porpoises) communicate almost exclusively using acoustics, a combination of echolocation, clicks, whistles, moans, grunts and singing as well as actively listening for these. When the ocean gets louder and they are competing acoustically with human driven noise, it gets harder for them to communicate with each other over the din. Some important information could be getting lost, whether that information is for social interactions and learning, pointing out that food is nearby or predator avoidance they are all necessary communications that could be getting lost in translation due to the overly loud human driven ocean noise party we have started. This doesn’t even take into account the stress this could cause and the effects noise disturbances and disruptions may have on the energy expenditures for the individuals of a species involved.
So what is being done about it?
Well there is some great research going on out there to see the impact that anthropogenic noise has on marine mammals. Such as the Behavioural Response of Australian Humpbacks whales to Seismic Surveys (BRAHSS) study which is looking exactly at its name sake and trying to quantify and understand it. Also in the northern hemisphere a recent publications by Williams et al., 2014 shows the response of killer whales to shipping traffic and the possible energetic costs these could cause. Further to these the IMO has also made recommendations for targets to be met for ocean noise reductions and offered guidelines for reducing shipping noise
But, we have a long, long way to go with the increased demand for consumer products worldwide, many of which are transport by ship, and a growing global populations. Meeting these demands will lead to more ships and bigger ships so there will have to be a concerted effort to make these ships quieter. Plus a continued effort by scientists to understand the full extent of the effects of anthropogenic noise in the marine environment, so that the correct mitigation measures can be implemented.