September 25, 2023
It’s hard to find a place that can serve as both a training ground for military ships and aircraft, and as a home to sensitive wildlife. With the help of Defence Research and Development Canada, the ocean can more safely be both. This capability was exemplified during Exercise CUTLASS FURY 2023, where defence scientists took to the seas to improve the safety of marine mammals.
Exercise CUTLASS FURY is a biennial NATO exercise that takes place in the North Atlantic, off the coast of Nova Scotia. The exercise is an opportunity for NATO Allies to gather and put their skills to the test in a simulated tactical marine environment. This year, the exercise ran from September 10 to 22.
Five days before the exercise took place, DRDC’s Marine Mammal Risk Mitigation (M3) program, in collaboration with Dalhousie University’s Coastal Environmental Observation Technology and Research group, sent out remotely controlled gliders which towed underwater microphones, known as hydrophones, in the area where the exercise was planned. These electric gliders look like a torpedo with wings and are about the length of an alligator. The hydrophones gathered real-time data on surrounding whale calls, which were analyzed to advise which areas the ships should avoid when using active sonar. Active sonar is when a ship sends out a 'ping', and then listens to the echoes on its sonar as that ping bounces off underwater objects. By contrast, passive sonar is simply listening underwater.
A first generation Slocum glider
"When ships use active sonar, they produce loud underwater sound that can affect nearby marine mammals, including changes to behaviour or hearing sensitivity. By measuring where marine mammal calls are present, we can conduct the exercise in areas less likely to contain marine mammals,” says Dr. Brendan Rideout, a defence scientist at DRDC’s Atlantic Research Centre. “Our goal is to minimize the risk of harm while enabling naval readiness."
Active sonar is an important tool in the detection and tracking of submarines, which makes the training in this exercise essential to prepare for anti-submarine warfare. However, by determining where the whales are located beforehand, DRDC can make recommendations to the Canadian Armed Forces to plan exercises in areas distant from known marine mammals, limiting the risks posed by its use.
Another marine monitoring tool is in development under the M3 program, called the “integrated marine mammal risk assessment and monitoring” system (IMMRAM). This system, currently a prototype, could be used to help leaders planning future exercises make decisions by presenting a large amount of data in an easy-to-understand format. IMMRAM will expand on Canada’s M3 capacities, combining data on marine mammals from a wide range of sources, both historical and real-time, to create a visual map of risky areas to turn on active sonar.
With these tools, the risk of causing harm to marine mammals during naval exercises can be mitigated. DRDC’s M3 program enables the Royal Canadian Navy to participate in important training exercises like Exercise CUTLASS FURY, all the while improving the protection of mammals underneath the surface.