Tagged beluga whale in the Eastern Beaufort Sea (left). Nigel Hussey and Luke Storrie releasing a tagged adult male beluga whale (right). Photos by Greg Elias and courtesy of Department of Fisheries and Oceans Canada. The noise generated by ships has had known impacts on many marine species with a focus on whales that use sound for foraging and social behaviours. Beluga whales (Delphinapterus leucas) are sensitive to high frequency sounds as their hearing is most sensitive from 20kHz to 75kHz with an upper limit of 125kHz. Most commercial vessels produce anthropogenic noise between 10 Hz to 63.1 kHz frequency with a sound pressure level of ~110 decibels (dB). Icebreaking ships produce noise between 20–1,000 Hz band up to 200dB (100-200dB). 100 decibels is approximately equated to a motorcycle at full speed, however sound behaves different in water relative to air where pressure becomes even more important. It was previously found that belugas can detect the sounds of icebreaking ships at 85km away and change their behaviour at more than 40km away. A recent study by Martin, et al. (2021) used telemetry tag data previously collected by the Department of Fisheries and Oceans Canada (DFO) to assess the responses of these tagged whales to ships in the area by pairing the tag data with the satellite AIS data Morgan and her team were able to assess the behavioural changes of the tagged whales. Previously studies looked at the change in behaviour from the surface. The introduction of the tag data allows the researchers to assess any changes in speed, acceleration and diving behaviours. The most common response to a vessel by belugas was a sharp turn to avoid the ship and sometimes doubling back to original course once the ship had passed. Whales also displayed other behaviours when coming into close proximity of a ship such as a steep 'V' shaped dive to depth, a shallow dive and course adjustment away from the noise and increased speed when swimming away from the ship. The response of marine organisms to anthropogenic noise sources is becoming increasingly important as reduced ice coverage in the Canadian Arctic opens those waterways for more vessel traffic. Understanding the responses of these organisms to vessels can help managers determine the best path to reducing impact in the face of increased vessel traffic. To find out more check out Morgan Martin's Google Scholar and an article by Hakai Magazine. Morgan Martin in the Canadian Arctic in 2022. Photo by Morgan Martin.
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