An update from Futurismo on their understanding of Orca populations off the South coast of São Miguel Island, Azores

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As we continue to demonstrate, Azores is a box full of surprises and wonders cetacean-wise. Orca (Orcinus orca), the biggest of the oceanic dolphins are one of the best examples. Most people, especially children recognise the charismatic, panda coloured animal immediately, however, little is known about this species and its populations in mid-Atlantic waters like the Azores. Orca differ very much in appearance, behaviour and culture, and their association with prey is linked with their movement patterns, site fidelity and dispersal. In the Azores, we occasionally are lucky enough to come across some individuals and we take every opportunity to keep our database growing.

Photo by Raphael Martins

Some of the data like GPS points, behaviour, group composition and photographs of nicks, scratches and colouration patters across the body are essential to a better understanding of their biology and ecology. Also, by looking at each individual’s particular characteristics and comparing our sightings with other research institutions and experts we can have a deeper picture of their movement patterns and try to answer some really important questions:

  1. To which population(s) do they belong?
  2. Where do they come from?
  3. Where do they go?
  4. What are they doing in the Azores?

These are just some of the questions that one of our biologists Georgina Cabayol, an orca passionate, has been trying to answer. This is what she has found!

Between 2006 and 2020, orcas were sighted in 33 different days (in 9 of the 15 years) on the South Coast of São Miguel island, Azores. Not much at all! As matriarchal groups, composed by the oldest female and her descendants, our sightings ranged between 1 and 10 individuals and comprehended adults (both males and females), juveniles and calves. Photographs of the sighted individuals allowed for the creation of a new catalogue with a total of 55 individuals photo-identified.

Sightings of Orcinus orca in the study area (2006-2020)

Of the 55 individuals, 17 were re-sighted, mostly within a few consecutive days. Some were re-sighted in groups, some alone. None were re-sighted between different years. However, as always, there are exceptions. An adult male whom we like to call “Mr. Ray” was re-sighted over five months in 2013!

Most of the orca sightings were made between March and May. Does this indicate that they prefer to come to the Azores in the spring months? If so, then why? Azores waters are known for a huge bloom of life in the springtime. Will this be the reason of such sightings? What about our sightings being mainly between 1 and 5 km of the coast and in areas of average depth between 300 and 700 m? Are these crossing corridors of prey-rich areas?

Temporal distribution of orca off São Miguel (2006-2020). Only years and months with sightings are shown on the graph

So much is still to answer and so much is still to understand. We hope to have new chances to see them soon and hopefully fill some of the gaps. Will they visit the Azores again? Will we recognise some of them? We have our fingers crossed!

If you’d like to discover more about our orca, check out this poster presented by Georgina last December in the XIX National Ecology Encounter, Portugal

Find out more about Futurismo here

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