Azores : Summary of the 16th expedition

Looking back on the 16th edition of our Biosphere Expeditions whale and dolphin citizen science expedition, the word that comes to mind is: remarkable.

It was the first expedition to run after two years of the Covid pandemic. A total of 23 whale and dolphin volunteers from all corners of the world joined Lisa, our scientist, and myself in Horta for whale and dolphin volunteer action. Except for one brave man, it was women power all around on this 16th expedition!

We were reminded of the volcanic nature of the Azores archipelago with a lot of seismic activity on the nearby island of São George, but an eruption never came. After two years of lockdowns, many of us had were keen to explore new horizons, gain news skills and most of all contribute to the conservation of these fascinating animal group of cetaceans.

No citizen scientists tested positive, there were no major issues, great sightings, excellent team spirit, a wealth of data and high degree of satisfaction for those involved. Let me summarise our findings in a nutshell for you:

In total three groups of Azores volunteers spent 16 days out at sea, adding up to almost 100 sea-hours while covering 1,674 km around the islands of Faial, Pico and São George. Our search effort resulted in 127 sightings of 10 different cetacean species. Every group was treated to a subset of these and each one had their unique sightings and highlights.

For Group 1 it was very impressive to come across a group of 75 false killer whales feeding on tuna with seabirds all around. Group 2’s most exciting moment was spotting our first blue whale in sea state 6 ‘all hands on deck’ and Group 3 definitely wins the prize of the rarest sighting ever, seeing a leucistic white humpback whale.

Working our way through the species list, no one will be surprised to hear that common dolphins ome in first in terms of abundance, with 48 sightings and a total of 1,800 individuals. Second comes the iconic sperm whale, Lisa’s main research focus, with 59 sightings. Baleen whales are known to migrate through Azorean waters in spring, hence the timing of our expedition. We were treated to six humpback whales during three different encounters, one minke whale just outside Horta harbour and three majestic blue whales. As for dolphins, most of which are resident, the well-known bottlenose dolphins were spotted five times, we saw mysterious Risso’s dolphins on four occasions and had two encounters with striped dolphins. Last but not least, group 1 also got lucky to see five elusive beaked whales.

But Biosphere Expeditions obviously goes beyond listing species and counting numbers. The main purpose of our expedition is to understand population dynamics, local movements, seasonal migration patterns, as well as group composition and reproduction. Out of the total of 59 sperm whale sightings, we managed to identify 44 individuals of which 18 (40%) are known individuals and 26 (60%) are new individuals of which fluke shots were added to the catalogue. We actually repeated one individual within the expedition, sighted both on 28 March as well as 19 April. Within the known individuals, there are three well-known groups: the one of nr 19 first seen in 1987, the group of 1598 and the group of 2808-2448-3483-6089 with calves of last year. We also spotted a few male sperm whales, one of which is known as Tiktok, that seem to be more resident around the Azores archipelago, often sighted close to São Miguel. This is rather unusual, as most males migrate to the Northern Atlantic for food, while the females are known to stick around.

As for the humpback whales, one of the North Atlantic experts for the species confirmed that one fluke shot we took was matched to an individual seen in October 2014 and in January 2015 in the Tromsø–Andenes region in the north of Norway. Our white humpback whale, called Willow, is rather unique, being the only known white individual in the Northern Atlantic. So based on this feature together with its fluke ID, we were able to confirm that this individual was seen in the breeding grounds of Guadeloupe in 2015, 2019, 2020 as well as in the feeding grounds of Spitzbergen in 2012. A tissue sample had been taken there, indicating Willow is a male. This demonstrates how every fluke photo adds pieces of the puzzle that make up the life history of these long-lived migrating baleen whales.

Regarding the blue whales, the two individuals we spotted travelling together were resightings from the Azores. One was seen there before in 2010 and the other one in 2006, 2010, 2014 and 2018, as confirmed by the expert Richard Sears, showing that at least some individuals use the same migration routes.

Dorsal fin photos were sorted by our whale citizen scientists and sent off to Karen Hartmann, expert of Risso’s dolphins, and to other colleagues working on bottlenose dolphins and false killer whales. These species are considered resident around the islands and we recognised some individuals with distinctive dorsal fins in groups of varying sizes, so as more feedback comes in form the experts, it will also generate increased understanding of these dolphin species.

This year we collaborated closely with the University of the Azores by testing the beta version of the Monicet app, which was released just before the start of the expedition. Our team provided several recommendations, which will be included in an improved version to be released by the end of April. The idea is to roll out the use of the Monicet app to all whale watching vessels in the Azores to further increase data collection and sharing.

We look forward seeing the first results published and were glad to contribute to these. We also worked with more advanced GPS units, which allowed to record tracks and sightings as you can see from the included maps, which show our sightings during March and April.

Lisa will continue to use this GPS and as more data get uploaded, it will give further insight into movements in space and time of different species, while understanding which are hotspot priority areas for feeding and resting that merit further protection.

Thanks again to Lisa for sharing her expertise with all of us, to captain Siso for sailing us safely through sometimes rough seas, to all lookouts on land for spotting the animals for us and to Jim and Claudia for being excellent hosts. Last but not least, a big thank you to an international team of expeditioners joining us and dedicating their free time, energy, resources and enthusiasm to collecting data and contributing to the conservation of these magnificent creatures of the sea. We hope to welcome more expeditioners in 2023 for expedition nr 17 to continue our long-term monitoring work.

Best wishes

An Bollen
Expedition leader