Have you ever been at a noisy party and couldn’t hear the guy next to you? Or been on your phone when a fire truck went by and you couldn’t hear the conversation? Or gone to a rock concert and had a “hearing hangover” for hours afterwards? This sort of thing happens in the ocean, too, except marine life can’t just leave the party or put in earplugs (well, most of them can’t, anyway).
Sound travels really well in seawater, but light does not, so ocean animals rely on sound for a variety of reasons. For example, New England’s oyster toadfish will signal his mate that he’s got a nest ready for spawning by making a “boat-whistle” call. Lots of other fish make and use noise not only to attract a mate, but to scare off predators, or tell other fish to stay out of their territory. Check out this fun set of fish calls to hear more. Marine mammals make noise, too – whales use sound to hunt, navigate, avoid predators, bond with their young, and generally communicate with each other.
But our oceans are getting noisier and it’s harder for marine life to use sound they way they need to. Too much noise can harm ocean animals in a variety of ways. It can cause temporary or permanent hearing loss, make it hard for the animal to find food, separate a mother and calf, or even lead to strandings or death. Shipping, ocean dredging, seismic surveys for energy development or seafloor mapping, military exercises, and fishing – all can make for a noisy ocean environment.
Researchers are only just starting to make progress in mapping out our ocean noise, to help us get a handle on how to reduce the impact of it on wildlife. For an example, look at these new maps of ocean noise in the North Atlantic. Unfortunately there is a lot of uncertainty about what kinds of sound are worst for marine life, and at what levels.
There is not a robust regulatory mechanism for addressing ocean noise pollution in a comprehensive way. The procedures for addressing harm to marine mammals differ among various sound producers—for example, commercial shippers, fishermen and aquaculture operators, the military, the oil and gas industry, and the academic community. In general, ocean and coastal resources are currently managed by more than 20 federal agencies and administered through a web of more than 140 different and often-conflicting laws and regulations.
We need to do better, and we can.
An example of how we can learn to better coordinate ocean noise and wild animals is right here in the Gulf of Maine. Our critically endangered North Atlantic right whales need to be able to hear and use sound even more than they need to be able to see. Researchers from the Cornell University Bioacoustics Research Program have spent the past few years studying whales and noise in Stellwagen Bank National Marine Sanctuary. They have found that today’s whales, as compared to 50 years ago, live in a world of “acoustic smog,” and that “cumulative noise from all the shipping traffic is making it difficult for all the right whales in the area to hear each other most of the time, not just once in a while.”
The researchers suggest that this new knowledge can help adapt current management tools and be used as part of “comprehensive plans that seek to manage the cumulative effects of offshore human activities on marine species and their habitats.”
They are on to something. This call for collaborative, data-driven, practical management is at the heart of Regional Ocean Planning. A good regional ocean planning process can help us coordinate our activities while minimizing and mitigating conflicts among ocean users and protecting healthy ecosystems. It is the process that recently helped researchers in Stellwagen Bank better protect whales from vessel strikes by shipping traffic. And it’s a process that can help us unravel the ocean noise puzzle – and better protect our hearing marine life, while continuing to develop our maritime economy.