The sounds of rare whales were recorded from the RV Noosfera

The sounds of rare whales were recorded from the RV Noosfera

Ukrainian scientists managed to meet rare whales and record their sounds. It is about Arnoux’s beaked whales this is one of the least studied species of whales in the world.

In the area of Akademik Vernadsky station they can be seen very rarely, but our scientists have established that further north, in the Gerlache Strait, there is a wide variety of marine mammals. In particular, encounters with Arnoux’s beaked whales are most often recorded there. That is why this area was chosen for research from the RV Noosfera.

The work continued in several directions. From aboard the RV Noosfera they conducted visual observations and performed “acoustic trawling” recording the sounds of cetaceans. Separately, the search for animals was carried out from a motor boat that moved nearby, but examined bays that were hard-to reach for a large vessel.

On the very first day of work, the boat crew was very lucky they noticed a group of 5 Arnoux’s beaked whales. The encounter lasted a few seconds, but the biologists managed to take a photo of the whales and transmitted information about the direction of their movement to Noosfera. Thanks to this, it was possible to record the sounds of Arnoux’s beaked whales from the ship.

A special acoustic system was used for recording. It consists of:

  • acoustic recorder built into a streamlined body;
  • cable 180 m long;
  • wings that hold the body with the recorder at a fixed depth;
  • shank to prevent excessive vibration.

This design allows you to make high-quality recordings while the vessel is moving, despite the acoustic noises it creates.

As a result of several sessions of the recorder, biologists received more than fourteen hours of acoustic recordings. A preliminary assessment of some of them showed the presence of sounds not only from Arnoux’s beaked whales, but also from killer whales and humpback whales. But a thorough analysis, which may reveal the sounds of other marine mammals, is still ahead.

We remind you that acoustic research at Vernadsky has been carried out since 2021. In particular, the scientists recorded various marine mammals from boats, and also kept continuous recordings during the Weddell seals breeding season near the station.

Also, for the second year running, Ukrainian biologists and American colleagues have been studying Antarctic whales using the method of passive acoustic monitoring. Several stationary acoustic recorders are installed near Anvers Island and they operate year-round.

Through such research, we will be able to improve our knowledge about marine mammals, in particular, their ways of communication.

For example, passive acoustic monitoring is especially valuable because it allows to learn about the seasonality of the presence of animals in places where it is impossible to organize constant observations involving people. But to interpret these data, you need to have a “dictionary” of acoustic patterns of different species, and it is not yet complete for Antarctic mammals.

Information: Oksana Savenko and Vadym Tkachenko

Photo: Vadym Tkachenko, Yuriy Shepeta, Anna Torgonenko