Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021

Erindi/veggspjald / Talk/poster V22

Humpback whale (Megaptera novaeangliae) activity on Icelandic feeding grounds on a year-round basis

Höfundar / Authors: Jóhanna Sigurðardóttir, Edda Elísabet Magnúsdóttir, Jörundur Svavarsson

Starfsvettvangur / Affiliations: Faculty of Life and Environmental Sciences, University of Iceland

Kynnir / Presenter: Jóhanna Sigurðardóttir

Humpback whales are large baleen whales which are known to forage in the subarctic waters of Iceland throughout the year, with the highest abundance from spring to fall as many migrate towards the equator during the winter breeding season. Humpback whales are increasingly sighted in Icelandic waters throughout the year, indicating a trade-off between breeding and feeding. In this study we investigated the diving behaviour in different seasons to better understand the cost of overwintering on a high latitude feeding ground. Seasonal changes in conditions, such as sea temperature, upwelling and photoperiod, as well as the humpback’s life history, is expected to influence their behaviour in the subarctic. The humpbacks’ surface behaviour was observed from land (breathing rate, dive duration, surface behaviour and group size) throughout the whole year. Three archival tags were attached to three humpback whales to assess if surface rate observed from land could indicate their underwater diving behaviour. The archival tags will also be used for calibrating the errors of the land-based data. Preliminary results show that the diving pattern varies between seasons with longer deep dives in the winter while the diving patterns varied substantially in summer. That indicates a greater effort placed into searching for prey during the colder months. Generalized linear regression analysis will be carried out to further study the impact of seasons and locations on their diving behaviour.