Recovery status and ecology of fin whales (Balaenoptera physalus) at the West Antarctic Peninsula

• Applicant: Dr. Helena Herr
• Subject Area: Oceanography
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 404353644

This project is an extension of the project 'Recovery status and ecology of fin whales (Balaenoptera physalus) at the West Antarctic Peninsula, proposed to complement and continue previous work investigating the post-exploitation status of fin whales at the Antarctic Peninsula. Southern Hemisphere fin whales were brought to near-extinction by industrial whaling of the 20th century. For decades, they had all but disappeared from previously highly frequented feeding grounds around the Antarctic Peninsula. Very little information existed on abundance and distribution, breeding grounds were not known, and information on migratory routes and destinations lacking. In the previous project period, we were able to confirm the return of fin whales to historical feeding grounds at the Antarctic Peninsula, including the first documentation of large fin whale feeding aggregations. High densities, re-establishment of historical behaviours and the return to ancestral feeding grounds suggest an ongoing recovery of the population. Furthermore, we conducted an analyses of the skin condition of fin whales based on high-resolution aerial imagery. A pristine skin condition and a high prevalance of cookiecutter shark bites provided first indication of a migratory destination in an offshore habitat with little human impacts within the sub-tropical distributional range of cookiecutter sharks. We then managed to successfully deploy for the first time four satellite transmitters on fin whales at the feeding grounds off the Antarctic Peninsulas. The tracks of the fin whales provided first evidence for a migration into the Pacific. However, the tags stopped transmitting while the animals were still in transit, before they had reached their migratory destination. Remaining important questions are (1) whether fin whales feeding at the WAP belong to one (breeding) population, or if they are converging from distinct, spatially explicit (sub-) populations, only mixing at the feeding grounds (2) where the wintering grounds of fin whales feeding at the WAP are located, and (3) what the aggregating fin whales in the WAP feed on and how they are distributed in relation to krill (species) distribution. During the proposed project extension, data collected during a dedicated fin whale research expedition will be analysed to answer these questions. (1) Data from a visual cetacean survey and a concurrent krill net sampling survey will be used to investigate predator prey relationships, complemented by fatty acid and stable isotope analyses of biopsy samples from fin whales (2) Transdermal implantable satellite tags will be deployed on fin whales for long-term tracking of migration after the feeding season (3) genetic analyses will establish information on population identity and population structure.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas - with renewal proposal 2025 - 2030
• International Connection: Poland, United Kingdom
• Cooperation Partners: Professorin Dr. Jennifer Jackson; Dr. Joanna Kershaw; Dr. Anna Panasiuk