Glacialis Expedition: Citizen Science for Humpbacks

Before going into any further detail, a brief recap is in order. Humpback whales in the North Atlantic use a number of feeding and breeding grounds. Studied for decades, the migratory routes of North Atlantic populations are well known and reflect the fidelity of individuals to their breeding and feeding areas. Humpbacks whose feeding grounds are located in western Greenland, for example, breed in the western Atlantic. Those that feed off Norway and Iceland are associated with all the breeding grounds of the North Atlantic, including those around Cabo Verde.

Implications of this discovery

A scientific article published by Valérie Chosson describes this new discovery. According to the article, the identification of NA04936 is the first confirmation of a migratory movement between Cabo Verde and western Greenland! Given that Indigenous communities in the region are authorized to harvest up to 10 humpbacks a year, subsistence hunting poses a risk to the recovery of this fragile population.

Between 1984 and 2007, the Greenland population increased by 9.4% annually. By 2024, the Greenland Institute of National Resources featured 466 individuals in its catalogue. However, humpbacks in western Greenland are in decline, and are beginning to gravitate toward a new feeding area in the eastern part of the region. This increases the likelihood that an individual will be harvested in the west!

Invaluable data sharing

Initiated by Virginie Wys and Mathieu Marzelière, the 2021 expedition redefined our understanding of humpback whale migrations in that it established a link between western Greenland and Cabo Verde. Beyond the implications for the conservation and management of the Cabo Verde population, this advancement underscores the importance of citizen science for conservation and the scientific community. During this expedition, three humpback whale matches were made.

The Glacialis expedition reinforces the idea that science can and should be a collaborative effort. This expedition was made possible with the help of crowdfunding and the full involvement of Captain Arnaud Conne of Atlas , who also provided his sailboat. The citizens who supported this independent project also played an important role, and their involvement contributed to furthering scientific knowledge. Furthermore, collected data were freely and openly shared with teams of international scientists. Above all, data sharing with other research centres and with the public is enriching.