The Azores is one of the few places on earth where Sicklefin devil rays gather in large groups. Very little is known about this species which visits the Azores every summer. We now know that these rays are among the ocean’s deepest divers, but otherwise they remain a mystery to us. The presence of predictable aggregations at seamounts in the archipelago is therefore highly important, providing a unique opportunity to study these animals.
Between June and October each year, one species of manta (Mobula birostris) and two species of devil rays (Mobula tarapacana and Mobula mobular) can be seen in the waters around these islands. The most commonly sighted is the large and charismatic Sicklefin devil ray (M. tarapacana). This species is well known for its golden color and is one of the largest species of devil ray, reaching wingspans of three meters. The Sicklefin devil ray is the only devil ray species to have unique ventral markings, similarly to manta rays, which lead the project to establish the world’s first photo-ID database for a devil ray species.
Whilst Sicklefin devil rays can be seen across the archipelago during the summer months, they are most consistently seen aggregating in large numbers at the seamounts of Ambrósio near Santa Maria, and Princesa Alice near Faial and Pico. All the rays that visit are mature adults, and many females are heavily pregnant, so it is likely that the seamounts are important for their reproduction. However, the exact reason why they visit them remains a mystery. What we do know is that these rays are not shy about interacting with divers. Their large aggregations, surprising size, and obvious curiosity makes for an incredible encounter and, therefore, many divers from all over the world visit the Azores specifically to see them.
Most of MCA’s work has been conducted in collaboration with local dive operators and their guests, who support the project as ‘Citizen Scientists’. Guests contribute any ID photos they capture on their dives, and dive operators report any sightings of mobulas made throughout the season. Apart from photo-ID the project has gathered data through remote video stations at the main aggregation sites. Recently, collaborations have been established in other regions for the use of new methodologies has the collection of genetic samples with the aim of studying the connectivity of the populations between different regions in the Atlantic Ocean.
The Manta Catalog Azores project aims to better understand the population dynamics and temporal patterns of occurrence of the mobulid rays found in the Azores and the Eastern Atlantic – a region where little data has been collected to understand these elusive rays.
Considering the Chilean devil ray’s highly migratory nature and current vulnerability, understanding its ecology and behaviour is necessary to support sound management and conservation actions. Additionally, with the rapid growth of the mobula diving industry in the region, it is important to understand the ecological role of these very specific aggregation sites and assess how regulation may avoid possible impacts at these locations.
In the future the project hopes to scale up the amount of ID data it collects from visiting divers, as well as further engage the wider local community with understanding the conservation and economic importance of the mobula rays that visit the region.
To achieve their goals, Manta Catalog Azores works to meet the following objectives:
1. Understand the seasonal dynamics of the presence of mobulids in the Azores;
2. Identify ecologically important habitats for mobulid species in the region, and understand the importance of aggregation sites;
3. Expand the use of photo-ID as a tool to study M. tarapacana in other regions and continue to build upon the photo-ID database for the Azores manta and devil rays;
4. Investigate the local and regional movements of mobulids around critical habitats in the Azores, through seasonal monitoring;
5. Comprehend the implications of oceanographic, atmospheric, and biophysical influences on the distribution and seasonal visitation of this species;
6. Develop education initiatives with local and national entities to promote mobulid ray research and conservation as well as sustainable eco-tourism. Increase education and awareness in Portugal of the conservation needs of these species. Raise awareness among the public using citizen science and the media.
7. Provide reliable information to support local government management and conservation efforts, including mobula diving regulations and carrying capacity.
8. Study M. tarapacana and M. birostris population genetics in the region and wider Atlantic;
9. Assess the degree of connectivity between different aggregation sites in the Azores and between the Azores and other regions in the Atlantic.
PROJECT LEADER - ANa SOBRAL
Ana’s connection with nature, and specially the ocean, was evident from the early age of 5. The desire to become a marine biologist stemmed from wanting not only to learn more about the marine environment, but also to work towards its conservation. As she grew, so did that passion, which drove her to complete her BSc degree in Biology at the University of the Algarve in 2010. The will to work in marine conservation made her travel abroad to Mozambique to participate in a whale shark and manta ray conservation project. It was there that she had her first encounter with a manta ray, an experience she will never forget. The curiosity and penetrating eyes of these wonderful and mysterious animals immediately fascinated and intrigued her.
In 2011, Ana left Mozambique to chase the old dream of going to the Azores Islands, and started her MSc degree there. Once there, she realised that this was one of the few places in the world where Sicklefin devil rays (Mobula tarapacana) gather in large groups. Having large groups of these rays basically in her ‘backyard’ made the Azores the perfect place to study them, and that is what she did. For the past seven years Ana has been collecting data on the occurrence of Mobulid rays, with the precious help of dive operators and citizen scientists, through the project Manta Catalog Azores. She hopes the results from this project allow us to better understand the biology and ecology of the mobulid species visiting the Azores every summer, as well as to assist in the design of effective conservation and management plans aimed at protecting their populations in this remote region of the North Atlantic Ocean.
Established the first Portuguese mobulid, and sickle fin devil ray photographic ID database which, so far, has documented more than 170 mobulids.
Established a wide network of collaborators with dive centres and whale watching companies in the region.
Collected tissue biopsy samples for genetic analysis to study population structure and assess connectivity between the Azores and other regions in the Atlantic Ocean.
Confirmed the presence of three mobulid species occurring in the Azores
Photos from the field
In the Media
Sponsors & Partners
Fondation Yves Rocher
Save Our Seas Foundation
Observatório do Mar dos Açores
Oceanário de Lisboa