During a recent Antarctic expedition, researchers made an exciting discovery—a rare species of whale known as the Arnoux’s beaked whale.
This expedition was part of a study by Wageningen Marine Research and their partners, who are investigating the relationship between sea ice and the food web of the Southern Ocean.
The research focuses on various components of this food web, including top predators like seabirds and marine mammals.
The expedition took place in the southern autumn of 2022 aboard the German icebreaker Polarstern.
To map the numbers and distribution of animals in the area, researchers used two methods.
First, while the ship was sailing, observers like Bram Feij from the Royal Netherlands Institute for Sea Research (NIOZ) and Susanne Kühn from Wageningen Marine Research counted the birds and marine mammals they saw from observation posts on the ship’s roof.
These posts provided some shelter from the wind, making it easier for the researchers to carry out their work.
Second, when the ship was stationary, the team used a helicopter to conduct additional counts. During these helicopter flights, the researchers spotted groups of Arnoux’s beaked whales three times.
This was remarkable because, during 11 previous Polarstern expeditions between 1988 and 2018, this species had never been seen.
The findings of this rare sighting have been published in the journal Marine Mammal Science.
Arnoux’s beaked whale is a species that is rarely observed, so there is little known about it. The researchers recognized the importance of sharing their findings with the scientific community. To better understand this species, they compiled all available information on sightings of Arnoux’s beaked whales from literature, the internet, and fellow researchers. During this search, they discovered old slides and videos from the 1980s and 1990s, created by colleagues from Wageningen Marine Research and the Alfred Wegener Institute in Germany. By combining this data with information from international whale research programs, the team identified a total of 108 sightings, accounting for 1,125 individual Arnoux’s beaked whales.
New Insights into Whale Distribution
The Southern Ocean is a challenging environment to study due to its thick sea ice, especially outside the summer months.
Additionally, Arnoux’s beaked whales make long, deep dives, so they don’t often appear on the water’s surface, making them even harder to spot. Despite these challenges, the collected data has provided new insights into the whale’s distribution and habitat.
Previously, it was thought that Arnoux’s beaked whales lived mainly in the deep parts of the oceans in the southern hemisphere. However, the new data shows that most sightings have been in relatively shallow waters, closer to shore.
There also seems to be a connection between the whales and sea ice, possibly for food or protection. Furthermore, sightings throughout the year suggest that these whales do not migrate to ice-free northern waters in winter, as once believed.
This research is part of the EWOS (Eastern Weddell Sea Observation System) pilot program, which aims to monitor the Antarctic ecosystem in the Weddell Sea over a long period and to establish standard monitoring methods. This work is crucial for creating a Marine Protected Area (MPA) in the Weddell Sea, helping to preserve this unique environment and its inhabitants.
