Acoustical Habitats and Aquatic Noise

I’ve just returned last week from the 2016 Aquatic Noise conference (AN2016), a gathering of souls who have taken it upon themselves to examine, poke, prod, regulate, and abuse our common interest in Marine Bioacoustics. This conference happens every few years and brings together regulators, academics, biologists, physical oceanographers, students, and at least one director of a conservation NGO – all rolling back the frontiers of our collective understanding about the impacts of human generated noise on marine life.

As meetings go this one is a bit unusual inasmuch as it is structured to  bring diverse stakeholders together in the same room, all experiencing the same program. There are no “side sessions,” plenaries, or discipline-segregated discussions. Almost all participants presented something, and we all got the chance to check each other out.AN2016 Meeting

 Aquatic Noise  Conference 2016, Dublin Ireland

This is the third Aquatic Noise conference I’ve attended (AN2010 in Cork Ireland, and AN 2013 in Budapest, Hungary). It has been by way of these conferences that Ocean Noise stakeholders – some of whom may otherwise be at odds about our respective roles in this wide and complex field, find ourselves sitting around the same tables dining and drinking with each other and getting a glimpse of the issues from behind each others dashboards.

This turns out to be incredibly productive. And while I didn’t find anything shockingly new being presented, the format allows for the juxtaposition of ideas and concerns in ways that naturally expand the conversation. For me an important advance that received much needed air was the systematic view of “soundscapes” and “acoustical habitats.” Regulators and noise makers find a reductionist view of noise impacts convenient; if a particular noise exceeds a particular exposure threshold it is “bad,” if it does not it is “O.K.” If they can keep an introduced noise below a particular threshold then it is O.K. If they cannot, they can ask NOAA Fisheries for “permission” to exceed the threshold by way of an “Incidental Harassment Authorization,”  (which is only occasionally denied).

If nature was so simple there would be no conflicts. But biology is not about trigger-points and thresholds, it is about relationships, adaptations, and habitat quality. As human enterprise expands into the ocean we are cluttering the acoustical habitat with all manner of new noises – from the mechanical artifacts of heavy equipment to the intentional signals of our control and communication technologies. Some of these will exceed regulatory thresholds, but many will not.

The operative term here though is “many.” A single piece of underwater communications equipment jingling away, the whirring of a pump, or the humming of a transformer may not itself exceed any specific threshold. But hundreds – or thousands of these pieces of equipment will definitely degrade the acoustical habitat for marine animals. This degradation may be in terms of “masking” biologically significant sounds, but more importantly (at least in my opinion) these noises will degrade the sound quality of the acoustical habitat.

There is yet no quantitative metric to express the quality of an acoustical habitat, but the phrase is now in play amongst all stakeholders. NOAA has canonized it in their recently issued “Ocean Noise Strategy Roadmap” so arguments substantiating acoustical habitat qualities are now on the table. Having this term in the room at the Aquatic Noise conference will only accelerate its use and adaptation.

2 comments for “Acoustical Habitats and Aquatic Noise

  1. Page Brownton
    July 31, 2016 at 3:48 am

    Keep up the good work!

    Page

    • mstocker
      August 2, 2016 at 6:07 pm

      Thanks!

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