Seychelles 2024

The Seychelles, an African nation located in the southwestern Indian Ocean and comprised of 115 islands, is world-famous for its vibrant shallow reefs, but much of the region’s deeper waters have remained a mystery. The waters surrounding the Seychelles are especially productive due to the Seychelles-Chagos Thermocline Ridge, a year-round upwelling area that brings nutrient-rich waters from the depths to the surface, attracting megafauna and sustaining a diverse array of marine life in the open ocean. Past research efforts have largely focused on the shallow and mesophotic ecosystems inner islands of the Seychelles Plateau. In contrast, the outer islands, consisting of coral atolls further into the Indian Ocean, remain understudied, especially in the deep ocean.  

These deep habitats are home to unique species, vital fisheries, and ecosystems that help sustain life in the Seychelles, yet they face growing pressures from climate change and human activity. Because accessing them requires advanced technology and significant resources, there is still much to be discovered in the deep-sea waters of the Seychelles that could inform protection and sustainable use of their resources. By combining the OceanXplorer’s state-of-the-art submersibles, underwater robots, and mapping systems, the month-long mission to the Seychelles conducted the deepest manned submersible and Remote Operated Vehicle (ROV) dives ever in the region, revealing what lies beneath for the first time.  

Using multibeam echo sounders (MBES), the team mapped over 22,600 km² of previously unmapped seafloor, including seamounts and the peaks and valleys of the Amirantes Trench, producing high-resolution bathymetric data critical for marine spatial planning. ROVs and manned submersibles conducted 52 video surveys and collected biological samples from habitats ranging from mesophotic reefs (~60–150 m) to depths of 4,603 m, documenting coral gardens, sponge grounds, and species never before recorded in Seychelles waters. Environmental DNA (eDNA) analysis from 209 water samples and 5 sediment samples revealed the presence of species without the need for capture, while Baited Remote Underwater Video Systems (BRUVS) — both shallow and pelagic — captured over 260 hours of footage, offering rare behavioral and distribution insights for sharks, turtles, and other pelagic fauna. These discoveries provide baseline biodiversity data, extend known species ranges, and highlight ecologically significant areas that could be prioritized for marine protected area (MPA) expansion. 

The expedition also strengthened the science behind sustainable fisheries management. Acoustic surveys and BRUVS footage identified pelagic fish and shark aggregation sites, while plankton tows and water column profiling pinpointed likely spawning areas and revealed larval dispersal patterns. Coupled with oceanographic measurements such as temperature, salinity, nutrient levels, and chlorophyll concentrations, these data help predict how climate variability could shift fish distributions.  

The mission’s collaborative approach was equally impactful. Seychellois students and researchers from the James Michel Blue Economy Research Institute at the University of Seychelles, along with numerous local scientists, took part in every stage of the research, from sampling and data collection to analysis. These collaborations built national capacity to carry out advanced and long-term marine monitoring. The mission’s research was focused on measuring the biodiversity of newly proclaimed MPAs in the Amirantes Group and Aldabra Atoll, leveraging new skills in tools such as sea-floor mapping, submersible dives, BRUV videos, and water quality sampling to understand the effectiveness of the management and establish baseline biodiversity for future comparative work over time. This deep dive of ocean literacy through the combination of technology-driven exploration and hands-on training directly strengthens ocean career paths and ensures the knowledge gained will directly support both MPA management and fisheries policies. 

Expanding beyond the region, the mission reached global audiences through livestreams, media coverage, and digital storytelling. Highlights included a live submersible broadcast to the World Economic Forum in Davos hosted by Dr. Diva Amon and Mattie Rodrigue, connecting the Seychelles’ deep sea to world leaders and decision-makers. By showcasing the value of ocean science in real time, the mission fostered ocean-positive decision-making, ensuring that both policymakers and the public see the ocean not as an abstract frontier, but as a vital, living system we depend on and must protect. 

This mission was built on close collaboration with the Republic of Seychelles, led by the Ministry of Agriculture, Climate Change and Environment (MACCE), and supported by a network of local conservation and research organizations. Partners such as the Seychelles Island Foundation (SIF), Island Conservation Society (ICS), Seychelles Fishing Authority (SFA), Save Our Seas Foundation (SOSF), and the Seychelles Climate and Conservation Adaptation Trust (SeyCCAT) each brought deep knowledge of local ecosystems and priorities. By combining OceanX’s advanced exploration tools with the expertise and stewardship of these institutions, the mission ensured that new discoveries directly feed into national conservation strategies, fisheries management, and blue economy goals, making it a truly Seychellois-driven effort with global scientific reach. 

Having conducted the deepest ever dives, mapped 22,555 square kilometers of the sea floor, and collected biodiversity data for the newly established MPAs of the Seychelles, this OceanX mission successfully supported national efforts to strengthen MPAs and apply new knowledge to sustainable fisheries management. These findings will also inform marine spatial planning across the Blue Economy Zone, ensuring that conservation and development move forward together.  

The mission also laid the groundwork for the future by building local expertise. The skills gained by Seychellois students and researchers during the expedition will continue to grow through national institutions, advancing ocean literacy, expanding career pathways in marine science, and strengthening the country’s ability to make informed, ocean-positive decisions.