‘The Coastal Soundscape of the Outer Bay of Fundy’ released June 2016 Journal
In April Eastern Charlotte Waterways released, ‘The Coastal Soundscape of the Outer Bay of Fundy’. It contained the methodology and results for the first assessment of underwater noise in the Outer Bay of Fundy, completed in partnership with Dr. John Terhune of the University of New Brunswick.
Noise is energy, waves travelling from a source at different frequencies and amplitudes. We purchased equipment to quantify it from Ocean Sonics in Great Village, Nova Scotia. Mark Wood and his team at Ocean Sonics are creating some of the world’s finest digital hydrophones, able to record sound between 10 and 12,500 Hz. The former number was very important to us. Baleen whales, of which there are an exceptional number in the Outer Fundy Bay, utilize frequencies between 10 and 100 Hz to communicate, so we needed equipment that could reach that low and provide an accurate reading.
In order to keep the hydrophone and its battery pack steady in the currents of the Bay of Fundy our field team stripped down and modified a crab pot. We called it the Hydropod. In May of 2015 we tossed the first one over the side of our skiff in Beaver Harbour, collecting the trial deployment the next day, excitedly listening to the garbled underwater noise of a random night in New Brunswick.
We ultimately deployed five of them last summer, recording the first two of every ten minute period between May and November. We ended up with about 110,000 recordings, give or take. Thanks to our data analyst and his wizardry (he keeps referring to a mysterious ‘R’ as the source of his powers) the primary question of analysis became, “Which information do we want to include in the report?”
The answer to that was found in the European Union’s Marine Strategy Framework Directive. The EU is currently leading the way in identifying thresholds for underwater noise. The MSFD identifies 63 Hz and 125 Hz as key frequencies, and an average of 100 dB re 1μPa (decibels relative to 1 micropascal) over a full year as the threshold for noise at those frequencies before it should be considered a pollutant.
Our results showed sound levels approaching that critical threshold in some areas of the Outer Bay of Fundy, with large amounts of spatial and temporal variability. Of note, Passamaquoddy Bay is a refuge from shipping noise, and Head Harbour Passage is an echo chamber. The full project report is available at ecwinc.org/noise. Moving forward, we have to effectively divide the available amplitude below the pollution threshold between renewable energy, a shipping increase, and a buffer for future use.
The project was a great success. With one year of monitoring completed, we now have the expertise to really tackle the question of noise in the Outer Bay of Fundy. It would not have been possible without the financial support of Environment Canada’s Gulf of Maine Initiative, the New Brunswick Environmental Trust Fund, and the New Brunswick Total Development Fund.