The Ocean Race
Seawater samples collected by sailors during The Ocean Race Europe 2025 could provide new insights into ocean hazards, such as algal blooms and jellyfish swarms. This is particularly timely, as shorelines across the Caribbean and beyond are still grappling with the impact of sargassum seaweed. This highlights the urgent need to better understand ocean biodiversity and the spread of invasive species. The data collected during the Race could help assess how climate change and human activity are driving these phenomena and identify potential risks in Europe’s seas. These preliminary results are being released today to coincide with World Ocean Day, a global event that aims to raise awareness about the ocean’s crucial role in sustaining life on Earth.
During last summer’s competition, Team Paprec Arkéa collected environmental DNA (eDNA) as they raced through the Mediterranean, covering over 2,000 nautical miles between Cartagena, Spain, and Boka Bay, Montenegro. These samples contain the genetic material left behind by organisms in the water, such as skin cells, mucus, and waste. By analyzing these traces, scientists from Citizens of the Sea were able to identify the presence of various species without direct observation or capture. The analysis of 24 samples yielded over 8.5 million DNA sequences and the detection of 2,365 types of bacteria and 785 plant and animal groups.
One of the most significant findings was the detection of the Mauve Stinger jellyfish, a species that is increasing due to climate change and overfishing. Most jellyfish monitoring is conducted near shore, providing only a limited view of their movements. Therefore, samples collected offshore during the Race could be invaluable in predicting future distribution patterns and mitigating the impact on tourism and fishing industries.
Species associated with harmful algal blooms (HABs), such as Alexandrium and Dinophysis, were also discovered. While this doesn’t necessarily indicate active blooms, their presence highlights the potential of eDNA as an early-warning tool. This tool could be crucial, as such blooms can produce dangerous toxins and cause harm to marine ecosystems, coastal economies, including fisheries, and human health.
Traces of the invasive Red Sea plume seaweed were detected offshore, despite it being a coastal species. This finding suggests that it may have spread further than previously thought. This could negatively impact Mediterranean seaweed forests by blocking sunlight, leading to a decrease in biodiversity.
Other non-indigenous species commonly associated with shipping and marine infrastructure, such as barnacles, reef-building worms, and colonial tunicates, were also detected. These findings emphasize the role of maritime activity in spreading invasive species and demonstrate how eDNA can help track these movements across vast ocean areas.
Stefan Raimund, the Science Programme Coordinator for The Ocean Race, stated, “Climate change and human activity are driving new marine threats, yet scientists know surprisingly little about many of the species and their movements. Sailing boats are what we call vessels of opportunity that can make a real difference when equipped with the right equipment. They offer many advantages over traditional research methods, providing a broader range of biodiversity data more quickly and at a lower cost. We aim to equip many more racing boats to collect eDNA in real-time and help scientists gain a better understanding of species and their distribution in our seas. This is vital to the health of the ocean, which we all depend on.”
The Ocean Race is a pioneer in eDNA collection on sailing boats. The 11th Hour Racing Team is currently gathering data during a leg of the The Ocean Race 2022-23. This initiative is part of The Ocean Race’s long-standing Science Programme, which leverages the power of sport to advance ocean research, expand global observation efforts, and accelerate action for ocean health.