Atlantine Boggio-Pasqua (MIO) defended his doctoral thesis on wednesday 27 may 2026 à 9h00 at the Oceanomed Amphitheatre, MIO Mediterranean Institute of Oceanography, Méditerranée Building, on the following topic: Biology and spatial ecology of the Atlantic pygmy devil ray (Mobula hypostoma): an integrative, multi-scale approach to its conservation.
Abstract
The Atlantic pygmy devil ray (Mobula hypostoma) is an endangered planktivorous ray for which knowledge of its ecology, biology, and population structure and size remains limited. To support effective management across its Atlantic range, this thesis provides the first integrative assessment of the species' taxonomy, distribution, population structure, and spatial ecology.
These questions were addressed across multiple scales by combining morphological data, genomic analyses, acoustic and satellite telemetry, trophic ecology approaches, species distribution modeling, and long-term observational datasets. The species was found to occupy a broad environmental niche primarily associated with neritic waters, exploiting a wide range of coastal and continental shelf habitats structured by dynamic productivity patterns. In the northeastern Gulf of Mexico, this ecological flexibility was reflected in the recurrent use of shallow coastal habitats, where juveniles and subadults aggregate seasonally to exploit dense mysid shrimp swarms, particularly Metamysidopsis swifti.
Movement data further revealed that M. hypostoma is highly mobile within coastal and shelf environments, supporting regional connectivity across the northern Gulf of Mexico. Ontogenetic patterns indicated increasing horizontal mobility with body size and larger individuals less frequently observed in shallow coastal habitats, suggesting a shift in habitat use across life stages. At the population scale, genomic analyses revealed strong genetic differentiation between eastern and western Atlantic populations, supporting the recognition of distinct management units, while no clear structure was detected within the western Atlantic.
Multiple complementary approaches converged to identify the Gulf of Mexico as a key region for the species, potentially supporting the most robust known population.
These findings provide a robust scientific basis for conservation and management of the species. The designation of a neotype, detailed morphological characterization, and the establishment of a size-weight relationship improve species identification and the interpretation of fisheries records. The feeding aggregation identified and characterized in this thesis, a migration corridor, and a putative nursery area, could be soon recognized as Important Shark and Ray Areas (ISRAs) in the Gulf of Mexico. In contrast, the scarcity of observations in the eastern Atlantic, despite historical records and increasing monitoring efforts, underscores the species’ vulnerability to overexploitation and the urgent need for targeted research and conservation in the region. Despite the achieved advances, key uncertainties remain regarding the frequency and impact of fisheries interactions, as well as life history traits such as age, growth, and fecundity.
Overall, this thesis demonstrates how integrating complementary approaches across disciplines and scales can substantially improve ecological understanding and inform conservation strategies for threatened data-poor marine species.
Key words
Mobula, conservation biology, acoustic telemetry, trophic ecology, spatial ecology, population genomics
Composition of the jury
- Mr Frédéric MENARD, Research Director at IRD – MIO, PhD supervisor,
- Mr François LE LOC’H, Research Director at IRD – LEMAR, Rapporteur,
- Mr Johann MOURIER, Junior Professor, University of Montpellier, Rapporteur,
- Ms Frédérique VIARD, Research Director at CNRS – ISEM, Examiner,
- Ms Lydie COUTURIER, Research Fellow at France Energies Marines, Examiner,
- Ms Valérie MICHOTEY, Professor at Aix-Marseille University, Examiner.