Ocean warming effects and reef manta cleaning station use
By using camera monitoring (MantaCam) information and temperature data (February 2023 to June 2025), this project aims to assess if and how the 2024 acute ocean-warming event and subsequent reef bleaching at D’Arros Island altered the visitation patterns of reef manta rays (Mobula alfredi) at the cleaning station.
Axelle Joutel
From the Mediterranean coast of France to international research programmes, my journey has been shaped by one constant: a deep fascination for the ocean and its living world. Passionate about animal welfare from an early age, I knew by the time I was 13 that marine biology was more than an interest; it was a calling.
Now, at 21, I am proud to join the SOSF team at D’Arros and take a decisive step towards the conservation of reefs and marine ecology – a long-held dream. My ambition is clear: to turn science into impactful conservation of the oceans.
Effects of the most recent acute ocean-warming event on the use of a cleaning station by reef manta rays at D’Arros Island, Seychelles
To analyse whether the 2024 ocean-warming event and the bleaching that subsequently occurred had any effect on reef manta ray visitation and behavioural patterns by relating habitat to behavioural metrics.
This study provides valuable insight into whether acute warming events and climate-driven coral bleaching influence the behaviour of a key marine species. The reef manta ray is classified as Vulnerable on the IUCN Red List and is facing global decline. Increasing our understanding of impacts on behaviour and habitat use that are related to climate change helps us to assess national and global risks that are usually not easy to quantify.
By linking temperature and reef condition to behavioural ecology, the study contributes to conservation management and to research into resilience to climate change. Understanding behavioural adaptations will help to predict the future responses of manta rays to changing reef conditions on a broader scale and inform conservation measures nationally for the species.
Coral reef ecosystems are among the most biodiverse habitats on earth and provide essential ecological services to marine life and coastal communities. Cleaning stations are specific reef sites where reef manta rays and other species interact with cleaner fish. They are also a place for social interaction among individuals and with other megafauna.
Mass coral bleaching driven by elevated sea-surface temperatures has caused the widespread loss of live coral and the structural degradation of reefs, which can change cleaner-fish communities and the visibility of stations, and thus the use of cleaning stations by visitors such as manta rays.
The overall aim is to evaluate whether an acute ocean-warming event that led to bleaching at the site in 2024 has affected patterns of use of cleaning stations in Seychelles by reef manta rays, and their cleaning behaviour. This will be achieved by:
- Quantifying manta ray visits (frequency and duration) before, during and after the ocean-warming event at the most closely monitored cleaning station in Seychelles.
- Using temperature data to determine the intensity of the warming event on the cleaning station, and using raw camera images to analyse the severity of bleaching and the indications of recovery at the cleaning station.
- Correlating habitat condition metrics (temperature, bleaching extent, coral recovery) with behavioural metrics (number of visits, seasonality, duration, frequency, life stages).
- Assessing potential shifts in cleaning behaviour between comparable timeframes or seasons before, during and after bleaching.