STUDENTS

 Over the years, the Manta Trust has supported a number of students pursuing a research career in manta and devil ray ecology, fisheries, and conservation. The support provided by the charity has come in the form of financial support, access to, and support in field locations, as well as mentoring and academic support.

CURRENT STUDENTS

There are currently a number of research students around the world pursuing a PhD or MSc in marine biology and conservation through the Manta Trust. Scroll down to read about some of the current projects the Manta Trust is supporting.

ANNA KNOCHEL

PhD Candidate at University of the Sunshine Coast

Environmental Drivers of Mobulid Movement and Habitat Use Across Space and Depth.

Marine epipelagic predators often exhibit complex diving and movement patterns as they navigate a seascape characterized by patchy and ephemeral resources. Among these, mobulid rays are some of the ocean’s most charismatic predators, occupying a unique ecological niche as the only planktivorous rays, and possessing a dorso-ventrally flattened body plan that distinguishes them from other large filter-feeders such as whale sharks and baleen whales. This dissertation investigates the spatial and vertical habitat use of three mobulid species across distinct oceanographic regions. Through a multi-species, multi-region approach, this research uses a combination of satellite telemetry, remote sensing, and ecological modelling to explore how environmental variables influence the movement decisions of reef manta rays (Mobula alfredi), oceanic manta rays (M. birostris), and spinetail devil rays (M. mobular).

In the Coral Sea of Papua New Guinea, I assess how intra-annual environmental variation driven by alternating monsoons impacts the habitat use and vertical occupation of a regional population of reef manta rays, focusing on the roles of sea surface temperature, regional productivity, and the mixed layer depth. In the Eastern Tropical Pacific Ocean, I evaluate whether persistent and real time oceanic fronts are driving the foraging behaviour of the oceanic manta ray using a multi-model framework and build a species distribution model to predict monthly habitat suitability along the coast of South America. Finally, in the Mediterranean Sea, I use archival time series data to test the hypotheses that spinetail devil rays track sound scattering layers and alter their vertical behaviour to thermoregulate.

Collectively, my work provides a comprehensive examination of how environmental factors drive the movement and habitat use of mobulid rays across different spatial and depth scales, uncovering previously unknown aspects of mobulid movement ecology in three ocean systems.

ALE ARANA SALINAS

PhD Candidate at the University of Edinburgh

Conservation genomics of manta and devil rays.

Manta and devil rays (mobulids) are among the most distinct and derived elasmobranchs, exhibiting adaptations to pelagic life and a history of short bursts of speciation linked to declining plankton availability. However, their populations are declining due to increasing demand for their gill plates, posing a risk of extinction before their evolutionary history is fully understood. Major knowledge gaps in population size, connectivity and demographic history currently hinder effective management. This project addresses these gaps through genomic analyses of globally sourced samples.

Firstly, I will analyse genetic diversity, effective population size, and connectivity on a global scale for two heavily traded species: Mobula mobular and Mobula thurstoni. Additionally, I will develop SNP panels to trace the geographic origin of illegally traded samples, providing stakeholder new tools for surveillance and enforcement. Finally, high-coverage whole-genome sequencing of all mobulid species will offer unprecedented insight into the group’s evolutionary history and genetic vulnerability. These analyses also aim to highlight current and future threats for devil rays in the Anthropocene based on the response of mobulids to past environmental changes.

Combining these different approaches of applied genomics, the project will ultimately support better-informed conservation decisions and international regulatory efforts for these globally endangered species.

Additional supporters: This project is primarily funded by the UKRI NERC Edinburgh Earth, Ecology and Environment Doctoral Training Partnership (E4 DTP), with the Manta Trust as a CASE partner.

JULIE HARTUP

PhD Candidate at University of Auckland

Examining the demographic structure, movement, diving ecology, and genetic connectivity of the reef manta ray, Mobula alfredi, in Micronesia.

My PhD research focuses on the ecology and conservation of the reef manta ray, Mobula alfredi, across Micronesia, a region comprising over 2,100 islands with limited existing data on these vulnerable rays. Combining long-term photo-identification, satellite telemetry, and genomic analyses, I aim to: (1) estimate population demographics at key sites in Guam, Yap, Pohnpei, and Palau; (2) characterize individual movement patterns and habitat use, including diving behavior; (3) assess genetic connectivity and population structure across the region; and (4) integrate these findings to inform effective, science-based management and conservation strategies. This comprehensive study will fill critical knowledge gaps in geography and ecology, supporting local and regional efforts to protect reef manta rays amid increasing fishing pressures and environmental change in the Western Pacific.

Additional Supporters: Micronesian Conservation Coalition, Guam Seagrant, Manta Ray Bay Resort, Pohnpei Dive Club, Palau Manta ID 

SIMON HILBOURNE

PhD Candidate at University of Cape Town

Demographics, movements and connectivity of oceanic manta rays in the Central North Indian Ocean.

Oceanic manta rays (Mobula birostris) are among the most iconic and charismatic species in the ocean, yet they remain poorly understood. These large, migratory elasmobranchs face mounting threats from targeted and bycatch fisheries as well as climate-driven changes to ocean productivity. Despite their global distribution, critical gaps remain in understanding their population structure, movement ecology, and connectivity, particularly across the Indian Ocean, a region where increasing human pressures coincide with high manta occurrence.

This PhD project seeks to address these knowledge gaps by investigating the population demographics, spatial ecology, and regional connectivity of oceanic manta rays across the central and northern Indian Ocean, with a focus on the Maldives and Sri Lanka. Using long-term sighting records of over 1,000 individuals, the research will explore demographic trends, sex ratios, site fidelity, and seasonality to provide the first robust baseline for this region. Satellite telemetry and environmental modelling will then be used to examine large-scale movements and the environmental drivers of manta distribution, as well as their overlap with regional fishing activity. Finally, stable isotope and genetic analyses will assess ecological and genetic connectivity between manta populations in the Maldives and Sri Lanka, providing insights into regional movement corridors and potential population structure. Together, these findings will inform evidence-based conservation strategies for M. birostris in the central Indian Ocean and guide future management and research priorities.

Additional supporters: Save Our Seas Foundation

RIKA OZAKI

PhD Candidate at Okinawa Institute of Science and Technology

In collaboration with Fish & Fisheries Lab at James Cook University

Ecology of mobulid rays in the Ryukyu Islands.

The Ryukyu Islands sit on the edge of the northern border of the Coral Triangle, a region globally recognised for high levels of marine diversity and endemism. While numerous snorkelling and dive operations are centred around mobulid ray (primarily manta ray) sightings, research in this area remains limited. Fundamental questions about their abundance, population demographics, regional and global connectivity, residency patterns, conservation status and threats posed by human activities remain unanswered.

This project aims to address these knowledge gaps by investigating mobulid ray horizontal and vertical distribution and habitat use across the Ryukyu Islands, examining population dynamics and connectivity between islands and the wider Western Pacific, identifying critical habitats, assessing post-release mortality from set-net fisheries, and exploring public sentiment and fishers’ attitudes towards mobulid rays.

Through this research, we hope to provide much-needed insights into the ecology of mobulid rays in the Ryukyu Islands—an area that, despite hosting the world’s longest-running manta ray photo identification database, still holds many mysteries about these iconic animals.

Additional Supporters: Dive Gobies, Colour Code Kumejima, Kumejima Sensui

JESSICA HAINES

PhD Candidate at University of Exeter, UK

Ecology and Conservation of Nursery Habitat used by Reef Manta Rays (Mobula alfredi) in Maldives.

To improve approaches in manta ray conservation it is important to develop a better understanding of the juvenile life stage of these animals. This research project aims to enhance our understanding of the youngest reef manta rays in Maldives. While research has been thoroughly conducted on the adult population in this region, juveniles have only been studied opportunistically. Key aspects of this research project include assessing whether Maamunagau Lagoon in Raa Atoll qualifies as a nursery ground for juvenile reef manta rays and exploring the fine-scale oceanographic and environmental drivers that make this site important, through collaboration with Physical Oceanographer Dr Phil Hosegood. Using the Maldives Manta Conservation Programme (MMCP)’s 36-year photo identification database, this project will track individuals' movements from birth to adulthood, assessing how habitat use and migratory patterns change during ontogeny. Additionally, this project will evaluate the anthropogenic impacts of boat traffic on manta rays, through drone footage and boat tracking data. Resulting in the creation of an evidence-based code of conduct for boats in aggregation areas, contributing to effective conservation measures and management plans for Marine Protected Areas (MPAs) in the Maldives.

Findings from this research will be important to aid conservation efforts in Maldives and fill knowledge gaps for manta ray conservation worldwide.

Additional Supporters: Maldives Manta Conservation Programme, InterContinental Maamunagau Maldives Resort, Exeter Marine, University of Plymouth (Dr Phil Hosegood), NERC GW4+Doctoral Training Partnership

 RACHEL NEWSOME

PhD Candidate at Murdoch University, Australia

Activity and energetics of reef manta rays (Mobula alfredi) in contrasting seascapes

This project aims to compare the movement, habitat use and energetics of reef manta rays from two differing seascapes, D’Arros Island and St Joseph Atoll in the Seychelle Islands and Ningaloo World Heritage Area, a fringing reef system in Western Australia. These sites not only offer an exciting experimental design through the comparison of manta ray behavioural ecology in contrasting seascapes but will also allow us to determine anthropogenic impact on reef manta rays by comparing the Seychelles (relatively ‘undisturbed’) with putative high tourism impact at Ningaloo. We will employ combined cutting-edge animal attached-tagging technologies comprised of movement and environmental sensors for the first time to determine the behaviour, habitat use and energetics of reef manta rays and the mechanisms that drive these movements. This project will provide insight into the spatial, temporal, environmental and anthropogenic mechanisms driving habitat selection and movement and behavioural patterns of reef manta rays.

 HANNAH MOLONEY

PhD candidate at the University of the Sunshine Coast, Australia

Oceanographic drivers of manta ray feeding ecology and behaviour

Hanifaru Bay in the Maldives hosts an ephemeral hotspot to the world’s largest feeding aggregation of manta rays. Hundreds of manta rays gather to feast on nutrient-rich zooplankton often adopting coordinated feeding strategies to improve their prey capture, improve hydrodynamic efficiency and avoid collisions. However, the oceanographic drivers, water properties and zooplankton dynamics that lead to such aggregations and behaviours remain a key knowledge gap in understanding the ecology and movement of mantas rays.

Faced with a changing climate that threatens to decrease zooplankton biomass at alarming rates, it is more important than ever to address questions that expand our understanding of sites like Hanifaru Bay to help protect the ecosystems and food sources of significance to manta rays and other planktivores.

This study also aims to explore an undescribed and potentially new manta ray aggregation site on the eastern coast of Australia. K’gari (Fraser Island) is the world’s largest sand island and borders the productive waters of the Great Sandy Marine Park. This site remains mostly open for fishing and is surrounded by an unprotected body of Commonwealth water with high levels of both recreational and commercial fishing activity. While manta rays are protected from targeted fishing in Australia, their interactions with bycatch and fishing gear at this site are unknown and potentially problematic. This study will support the effective management of this site and ensure the safeguarding of the east-coast Australian manta rays.

 PAST STUDENTS