The goal of our 2020 season's fieldwork was to check the feasibility of our field-methods which involved the use of a drone to look at the behavior of common dolphins. While the COVID-19 pandemic messed up our lives, it also provided quite unique settings on the waters of São Miguel, Azores. Travel restrictions strongly limited the number of tourists on the island and, consequently, the number of dolphin-and-whale-watching boats operating around the dolphins. Some companies allowed us to make use of their boats and we had the great opportunity to observe dolphins in absence of any tourism activity. The past year we had a glimpse into the lives of São Miguel's common dolphins and we learned what was possible and what was not in terms of methodology.
A glimpse into the lives of the dolphins
During 2020 We spent about 42 hours at sea in 12 different expeditions. We encountered common dolphins in 10 of these trips, and we managed to film their behavior for a total of 8 hours and 20 minutes. Groups varied in size from 4 to 73 individuals, and in one occasion we could count 19 (NINETEEN!!!) mother-calf pairs (see images below). Thanks to these trips we could establish the best altitude to fly to count all the individuals in the pod and to collect data on the group behavior. Nevertheless, the footage will allow us to develop a more time-efficient procedure to determine group size.
The pod of 73, Dividing the group in clusters helps the manual count. Finally, the number of mother-calf (MCs) pairs was determined.
Since we could rewind the aerial video over and over again, we started to notice other interesting things beneath the surface. We were not only seeing dolphins in our frames.
Let's take a look:
And zoom in:
a. Dolphins b. Tunas
As you can see in the two images above, which are equally zoomed in, some tunas were even larger than the common dolphins (>2.5 m)!
Among the 12 trips we encountered some other species as well. From upper left, to lower right: Risso's dolphins (Grampus griseus), and Atlantic spotted dolphins (Stenella frontalis), bottlenose dolphins (Tursiops truncatus), and striped dolphins (Stenella coeruleoalba).
Are you curious of where we had our sightings? Here's the map of all our sightings in 2020 which we entered into the MONICET Database:
São Miguel sightings map (2020). Source map São Miguel: Flanders Marine Institute (2018). IHO Sea Areas, version 3. Available online at https://www.marineregions.org/ https://doi.org/10.14284/323
Drone dramas
Are you a drone pilot? If yes, you have certainly experienced some drone dramas!
Dolphins and No-Fly Zone
The surroundings of an airfield are never good spots to plan a drone flight and Ponta Delgada airport makes no exception to this golden rule. The local airstrip is basically on the cliffs aside the ocean and the landing corridor (see orange rectangle on the map below) right on top of the city's harbor. Even more importantly for us, the special permit fly-zone (blue oval) extends over the adjacent sea covering a quite large portion of the coastal waters. Of course, common dolphins know nothing about flying restrictions and in one occasion they decided to cruise slowly on the no-fly zone edge for about two hours! Armed with our best patience, we followed them at a distance until they finally moved out of the area.
Source: DJI innovations website
The Lithium Curse
Drones have lithium batteries. Damaged lithium batteries can burn like hell. Airlines do not like lithium batteries. This simple equation has become well known to anyone travelling by plane carrying a drone as a stowaway. But what if you are ordering a drone+batteries set to be shipped in a remote island? Well, do not expect that everything will go smoothly, even if you are dealing with experienced dealers! Our drone+12 lithium batteries took almost two
months to land in São Miguel as it was ping-ponged between the Portuguese mainland custom offices and shipping companies. Now we can laugh about this odyssey, but nobody will give us back the two potential months of data collection.
Photo credit: Anxo Cao
Into a new field season!
We are currently preparing for the 2021 season, which will start in May 2021, if the current circumstances will allow it. Stay tuned for our updates on Facebook, Instagram, and Twitter!
Acknowledgements
We would like to thank the Prins Bernhard Cultuurfonds for funding the main researcher for the 2020 and 2021 season. A big thank goes to Terra Azul and Picos de Aventura who each supported 6 of our trips by lending us their boats. We would like to extend our acknowledgements to the University of Azores which provided logistic support. Thanks also to IDEA WILD for providing equipment. A massive thank you to Renato Ferreirinha who helped us with all his heart during this season as a skipper, Nuno Pimentel, Tadeu Afonso, Noni Ortolano for skippering the boat, Tiago Batista for the media support and being a skipper, and to the look-outs of Picos de Aventua, Terra Azul, and Futurismo. We owe you a MASSIVE "Obrigado/a"!
We cannot forget our logo developer who has impressive artistic and design skills (logo left) Anxo Cão, and for the media support,THANK YOU! Lastly, thank you to Wageningen University for the full equipment support and supervision.
All data is collected under the license for data collection on cetaceans number LMAS-DRAM/2020/ 04, and drone footage under the permit from AAN, and drone flown by Dr. Lorenzo Fiori, a certified drone pilot.
Authors: the Azores Delphis Project field- team
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