Listening in: Sounds of minke whales recorded for first time

Minke whale

A minke whale

12 March 2019 by Euan Paterson

The minke whale is one of the largest marine species regularly visiting the Scottish coast, but its secretive and unpredictable lifestyle means much of its behaviour remains a mystery.

Now marine mammal researchers at the Scottish Association for Marine Science (SAMS) and Marine Scotland Science (MSS) have recorded the sounds of minke whales off Scotland's east coast for the first time, as they seek to learn more about these unique creatures.

Their findings were drawn from data collected as part of the East Coast Marine Mammal Acoustic Study (ECOMMAS) collection of underwater sound recorders, a long term Scottish Government monitoring project.

ECOMMAS was developed primarily to monitor the population of bottlenose dolphins to the east of Scotland. But SAMS marine ecologist Dr Denise Risch and her colleagues from Cornell University used software they developed to pick out the minke whale's underwater sounds, known as pulse trains, from two years of recordings.

Dr Risch said:

Although minke whales are often seen around Scotland, they have so far rarely been recorded acoustically. Their calls are produced at lower frequencies compared to those of other species like dolphins, which makes them difficult to record from moving platforms, such as boats.

By using static underwater recorders, the Marine Scotland Science team were able to record minke whale sounds near to the Scottish east coast, which is really exciting. To get a better idea of how animals use these sounds and how we can use them to assess populations, we need more year-round recordings further from shore, because low frequencies do not travel well in shallow waters.

Minke whales can grow to 8-10 metres in length but are hard to track because of their behaviour. Unlike humpback whales and dolphins, they do not 'display' when they come to the surface.

Despite being sighted around the globe, the whereabouts of minke whale breeding grounds and migration routes are not clear.

Dr Risch, who has also studied minke whales off the east coast of North America and Antarctica, explained:

Acoustically, the minke populations across the globe are very different. They have very pronounced accents based on where they are in the world. We've studies the humpback whale song for the past 40 years but the minke whale sounds across the world were described relatively late, which just adds to its mystery. There is a lot we still have to learn, but what we do know about the minke whale is fascinating.

Dr Risch will now use the same methodology to monitor minke whales on the west coast of Scotland, as part of the SAMS Collaborative Oceanography & Monitoring for Protected Areas & Species (COMPASS) project.

Scottish Parliament Environment Secretary Roseanna Cunningham said:

This exciting study highlights how we might use acoustic monitoring to study the presence and distribution of whales in Scottish waters. It is also testament to the excellent collaboration between Marine Scotland Science and SAMS, that builds on international research in the US.