Sei whale research

Sei whales (Balaenoptera borealis) are currently classified as globally Endangered by the International Union for Conservation of Nature, due to heavy exploitation and population decline during commercial whaling operations in the 1900s. Relatively little is understood about the modern-day distribution and ecology of sei whales worldwide, since in many geographic regions they are found primarily in offshore habitats and their occurrence can be less predictable than other baleen whale species – both factors making the species costly and logistically-challenging to study.

Southern Hemisphere sei whales have been increasingly observed in the coastal waters around the Falkland Islands (south-west Atlantic) since the 1990s, providing the opportunity to initiate one of the first targeted field studies of the species globally. Caroline has worked in the Islands for Falklands Conservation since 2016, initially carrying out a baseline survey of sei whales during the 2017 field season and then continuing to develop the research programme with a range of experienced project partners over the subsequent years. The work carried out on sei whales to date includes:

• Visual surveys of spatio-temporal distribution and abundance using shore, vessel and aerial platforms;
• Photo-identification work to identify individual whales and investigate their movements, population size, and associations;
• Satellite tracking to collect data on movements, habitat use, and dive behaviour;
• Faecal sampling to examine diet, parasites and to extract whale DNA;
• Biopsy sampling to collect small tissue samples to carry out genetic, stable isotope and hormone analysis;
• Acoustic monitoring to characterise the vocal repertoire of sei whales and assess their temporal occurrence;

• Behavioural work to assess the dive times and surfacing characteristics of sei whales around the Falkland Islands;
• Suction-cup tagging to document foraging behaviour;
• Unmanned aerial vehicle (or ‘drone’) work to assess body condition and health (commencing in 2024);
• Attendance of sei whale strandings to collect data on morphology, tissue samples and causes of death.

In combination, the work is providing a large amount of novel systematic information on sei whale occurrence that can be used to inform conservation and management decisions. The data have already been used to successfully recognise the Falkland Islands Inner Shelf Waters as both a Key Biodiversity Area (KBA) and as an Important Marine Mammal Area (IMMA) for sei whales, highlighting the global significance of Falklands’ waters for the species. Outputs from the ongoing work, including scientific papers, will be listed below as they become available.

Core funders of the Falklands’ sei whale research have included Falklands Conservation, EU BEST 2.0, the Royal Society for the Protection of Birds, Falkland Islands Government and Darwin Plus (DPLUS082 and DPLUS126).