Sei whale



The Falkland Islands are one of the few places in the world where sei whales can be regularly seen from shore; this offers an unparalleled opportunity to research these marine mammals and to learn more about what makes these waters so special. The ultimate goal of this research is to document their distribution, ecology and population structure in order to implement evidence-based conservation and management.

Sei whales were heavily exploited during the whaling era, resulting in their current Endangered global status. While whaling has ceased in most regions, current threats may include vessel collisions, entanglement in fishing gear, prey reduction, contaminants, harmful algal blooms, and disturbance from shipping noise. Work is ongoing to further understanding of Falklands’ sei whales, and to determine the best methods for their long-term conservation.


The culmination of research from 2017 to 2021 saw the nearshore waters of the Falkland Islands being recognised as a Key Biodiversity Area for sei whales. This is an international designation, driven by robust data, which confirms that this region is truly exceptional for sei whales on a global scale. The KBA will comprise an important tool to feed into ongoing marine management in the Falkland Islands. Not only is this the first KBA for endangered sei whales globally, but it is the first KBA to be confirmed using scientific criteria for any species of whale.

The Falkland Islands Inner Shelf Waters KBA for sei whales covers the nearshore waters of the islands, from the shoreline to 100m water depth. The initial application was submitted to the KBA Committee in 2020 following local stakeholder consultation, and was accepted as a confirmed KBA in April 2021.





Between 2017 and 2021, research carried out by FC has provided the critical data needed to scientifically assess whether Falklands’ waters qualify as a KBA for sei whales:

Distribution data and habitat modelling support a high occurrence of sei whales around the Falklands, from the coast to at least 100 m water depth;

Boat survey data and acoustic monitoring show a high seasonal presence throughout (at least) January to May;

A scientific survey off the west coast of the Falklands in Feb/Mar 2018 revealed a globally-significant abundance (~900 animals);

Photo-identification data has shown that some of the same sei whales return to the Falklands in different years, supporting long-term use of the region, and that within years, the same individuals stay in the Falklands over periods of several weeks and months, indicating that the area provides an important resource for sei whales;

Observations of defecation and surface-feeding behaviour support the use of Falklands’ waters as a summer/autumn feeding ground.



The driving factor behind the sei whale research from 2017 onwards has been to further local and global understanding of this endangered species, and to assess whether Falklands’ waters might meet the criteria for a Key Biodiversity Area. As part of this work, there have been a number of distinct but integrated projects and partners.

2017: Developing a site-based conservation approach for sei whales (Balaenoptera borealis) at Berkeley Sound, Falkland Islands. Funded by EU BEST 2.0. This pilot study investigated the distribution, population size and ecology of sei whales at Berkeley Sound in East Falkland during 2017 using land, sea, and air surveys. The project included the development of a photo identification database of sei whales in the Falkland Islands, which has formed the backbone for later research.

2017: Genetic diversity of Falkland sei whales. Funded by the Royal Society for the Protection of Birds (RSPB). This grant introduced biopsy sampling of live animals (under a FIG research licence) to compliment the abundance and distribution data being gathered during small boat surveys in 2017. Information on sex ratios, genetics, and feeding ecology is all possible through genetic sampling. In addition to live whale sampling which has continued throughout subsequent projects, genetic samples have also been acquired since 2017 from dead stranded animals and from historic whale bones at settlements and the New Island whaling station.

2017-2018: Assessing the behaviour of endangered sei whales (Balaenoptera borealis) off West Falkland. Funded by RSPB, Falkland Islands Government Environmental Studies Budget, and Falklands Conservation. A survey of sei whales on the west coast of West Falkland was carried out during 2018, and collected information on the distribution, behaviour, abundance and ecology of sei whales. The abundance survey formed a critical part of the KBA assessment.

2018-2021: Conserving Falklands’ whale populations: addressing data deficiencies for informed management. Funded by Darwin Plus and Falklands Conservation. This project partnered with several global specialists to advance understanding of sei whales and southern right whales in two coastal sites: Berkeley Sound and Falkland Sound. This multi-year project built on the data collection from previous studies, including photo identification and distribution surveys, and also used new technology to provide fresh insights. Acoustic monitoring was used as a long-term monitoring method for baleen whales, while suction-cup tagging was trialled to acquire more information on the movements, dive behaviour and foraging of sei whales. A significant and tangible result from this project was the designation of the nearshore waters of the Falkland Islands as a Key Biodiversity Area for sei whales.



The below 15 minute documentary was filmed alongside our 2020 whale surveys, and delves into the lives of the sei and southern right whales of the Falkland Islands, as well as the research that we have been undertaking to learn more about these fantastic whales.

Follow @FalklandsWhale on facebook.


Sei whales


A number of publications and articles have been produced since this research began in 2017. Please contact Falklands Conservation to request articles or more information.


Weir, C.R. (2021). Supporting evidence for the proposal of Falkland Islands Inner Shelf Waters as a KBA for endangered sei whales (Balaenoptera borealis). Falklands Conservation, Stanley, Falkland Islands. 36pp.

Weir, C.R., Taylor, M., Jelbes, P.A.Q., Stanworth, A. and Hammond, P.S. (2021). Distribution and abundance of sei whales off the west coast of the Falkland Islands. Marine Mammal Science,

Baines, M. and Weir, C.R. (2020). Predicting suitable coastal habitat for sei whales, southern right whales and dolphins around the Falkland Islands. PLOS ONE 15(12): e0244068.

Weir, C.R., Oms, G., Baracho-Neto, C.G., Wedekin, L.L. and Daura-Jorge, F.G. (2020). Migratory movement of a sei whale (Balaenoptera borealis) between Brazil and the Falkland Islands (Malvinas). Marine Mammal Science, 36: 1050–1057. DOI: 10.1111/mms.12687

Cetacean code of conduct for the Falkland Islands (2020). Falklands Conservation: Version 2, July 2020. Available to download at:

Weir, C.R., Stanworth, A., Cartwright, S., Jelbes, P.A.Q., Taylor, M. and Pompert, J. (2019). Distribution and movements of sei whales (Balaenoptera borealis) on coastal feeding grounds in the Falkland Islands (Malvinas). World Marine Mammal Conference, Barcelona, Spain, December 2019.

Buss, D., Jackson, J. A., O’Connell, T.C., Goodall-Copestake, W.P., Carroll, E.L., Foote, A., Barnes, I., Brace, S., Stowasser, G., Trathan, P., Jelbes, P.A.Q, Taylor, M., Stanworth, A. and Weir, C.R. (2019). Understanding diet, past and present: Insights into the foraging ecology of Falkland Island sei whales using DNA metabarcoding and stable isotope analysis. World Marine Mammal Conference, Barcelona, Spain, December 2019.

Weir, C.R., Taylor, M., Jelbes, P.A.Q. and Stanworth, A. (2018). Cue rates and surfacing characteristics of sei whales (Balaenoptera borealis) in the Falkland Islands. Journal of Cetacean Research and Management, 19: 43–55.

Weir, C.R. (2018). A preliminary assessment of endangered sei whales (Balaenoptera borealis) in two candidate Key Biodiversity Areas in West Falkland. Falklands Conservation report. Version 1.1 Draft, 27 August 2018. 128 pp.

Weir, C.R. (2017). Developing a site-based conservation approach for sei whales Balaenoptera borealis at Berkeley Sound, Falkland Islands. Falklands Conservation report. Version 1.0, September 2017. 115 pp.

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