Mitigating risks to marine mammals

NATO strives to better share the oceans

  • 18 Oct. 2010 -
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  • Last updated: 18 Oct. 2010 17:43

About 10 years ago, a group of whales beached on a Greek island shortly after the NATO Undersea Research Centre (NURC) had been conducting sonar tests nearby. NURC researchers tried to determine if there was a connection, but concluded that they just didn’t know enough about the mammals.


Since then, advances in knowledge and technology have much improved. NURC recently carried out a 45-day research project in the Atlantic Ocean to learn more marine mammals, their habitat and their behavior.

Sharing the ocean

For defence, active sonar exercises are essential to counter the threat from stealthy submarines. Because these sounds might impact marine mammals, NURC has taken an active role in determining the risks and mitigating them.

Scientist Kendra Ryan says that little was known a decade ago about the whale species that might be affected by sonar noise NATO produces during its naval exercises. “But now we actually understand their baseline characteristics, their habitat, but most importantly where they’re vocalizing.” This enables marine scientists to observe the mammals not only on the surface, but below as well.

Ryan was part of a team of scientists and acoustic specialists that departed from NURC’s home base of La Spezia, Italy, for the ocean off Portugal on board the NURC research vessel “Alliance”. They are passionate about their work and keen to demonstrate how preserving the sea life environment is beneficial to humans. For many of them, working in marine research is more than just a job.

The “Serena” cruise took place throughout last May and into June.

The perfect ship

The “Alliance” was built during the Cold War for anti-submarine warfare research and designed to be as silent in the water as possible. All engines are enclosed and every flat surface below sea level has an acoustic covering, reducing noise and vibrations. The vessel is at its quietest when running on battery power and the use of high quality fuel helps minimize exhaust emissions.

As Captain Helge Wrage explains, these features make the ship the perfect choice for the mitigation project, providing a unique research platform which allows “clean data acquisition”. However, the Captain also points out that the ship is so silent that it poses a risk to submarines, so the crew needs to keep them informed of its location.

The right equipment

Equipped with super strength binoculars, the marine biologists on deck observed animals as far as 13 kilometres away. Having spotted one, they would record its location along with any other information about the mammal and its behaviour.

Meanwhile, the acoustic team some decks below recorded sounds – such as dolphins clicking and whistling – within their hearing range and beyond. Thanks to sophisticated software and equipment the specialist could pinpoint not only distance, but locations as well – including depth.

Although visual and acoustic teams work together on board, the focus is on the acoustic data collection, which provides a 24/7 “eye into the ocean”. It can be used even in bad weather, unlike the visual equipment that needs to be protected from rain. The location of the mammals can be passed on to NATO vessels so that operations can be carried out away from them.

We developed this type of work more than 10 years ago,” says bioacoustics professor Gianni Pavan. But over the years, he and others tested and developed a range of instruments to detect and display the wide range of sounds outside the human hearing range. This has greatly increased their understanding of the different types of signals the animals produce. In many cases, Pavan says they can even distinguish between different species.

The vast amount of data the team has collected is being analysed to help NATO determine what kinds of animals they may encounter on naval exercises and how they can best mitigate any risk to them.

NURC falls under Allied Command Transformation, the branch of NATO responsible for modernising the way the Alliance works.