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Sei Whales

Sei Whales

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 Developing a site-based conservation approach for sei whales (Balaenoptera borealis) at Berkeley Sound, Falkland Islands

Project overview

The sei whale (Balaenoptera borealis) is a species of large baleen whale that is distributed in North Atlantic, North Pacific and Southern Hemisphere waters. The species migrates seasonally, using tropical and subtropical areas during the winter and moving to higher-latitude temperate areas in summer. In the Falkland Islands, sei whales are primarily sighted during the summer and autumn between January and April.

Berkeley Sound (including outer Port William and the waters around Cape Pembroke) has been identified as a ‘hotspot’ of sei whale occurrence and consequently proposed as a candidate Key Biodiversity Area. It is also the busiest area for vessel traffic in the Falklands, with current activities including trans-shipping, re-fuelling operations, anchoring, transits (e.g. cruise ships entering Stanley) and whale-watching. Vessel activity may also increase in relation to the emerging hydrocarbon industry.

The project aims to improve knowledge of sei whales in the Falkland Islands, increase awareness and provide information on the potential for interaction between whales and human activities. Finance for the project is being provided by the BEST 2.0 Programme funded by the European Union.

Study Area lr Approximate area of the sei whale study

Why study sei whales?

Sei whales are very poorly-studied worldwide because they have an unpredictable occurrence and usually inhabit deep, offshore habitat that is inaccessible to most scientists. However, sei whales occur near to the coast in the Falkland Islands, making this area an ideal location for a pilot field study.

The sei whale is of conservation concern, being currently classified as Endangered on the IUCN Red List. Southern Hemisphere populations were heavily reduced by commercial whaling in the 1900s. The present status of the South Atlantic population is still relatively unknown and no specific studies have been undertaken previously at the Falklands.

There is anecdotal evidence that sei whales have been increasing in coastal Falkland waters in the last decade, potentially bringing them into greater contact with human activities.

Sei whale 1 lr

Project objectives

The project aims to collect baseline data on whale occurrence in the study area, including:

  • Species identification;

  • Spatial distribution and habitat use;

  • Seasonality;

  • Group size and composition;

  • Behaviour;

  • Abundance;

  • Potential for interactions between whales and marine activities (if any).


Study methods

The pilot study will use a variety of techniques to collect information, including:

  • Stakeholder consultations – To acquire background information on human activities in the area and anecdotal information on whale occurrence;

  • Shore-based watches – To monitor temporal trends over the summer and acquire data on whale behaviour;

  • Boat-based surveys – To collect photo-identification images to monitor the movements of individual animals;

  • Aerial surveys – To examine abundance, spatial distribution and habitat;

  • GIS – Use of a geographic information system (GIS) to map sei whale sightings against environmental variables (e.g. water depth, sea surface temperature) and human activities.


Sei whale2 lrThe photo-identification method will use scars, nicks and shape of the dorsal fin to identify individuals.

How can you help?

We are trying to collect as much information on sei whales in Falkland waters as possible during the field season. If you would like to report a sighting of sei whales then please download and complete the sighting form or send an email to the project officer.

We are also compiling a photographic catalogue of sei whales and are seeking images of whales from all around the Falkland Islands. If you have photographs or video of sei whales then please send us an email.

The sei whale project officer Caroline Weir can be contacted at or by telephoning the Falklands Conservation office (+500 22247).


 pdfHow_to_photograph_whales.pdf153.75 KB

 pdfSei_whale_sighting_form.pdf119.5 KB

 pdfSei_Whale_Berkeley_Sound_Study_Report.pdf6.11 MB