According to new research, large ocean species can be protected in large Marine Protected Areas (MPAs) for a large portion of their lifecycles.

The Chagos Archipelago MPA is a 640,000 km² protected area in the Indian Ocean where the study monitored the migrations of seabirds, manta rays, and sea turtles.

Findings revealed that 95% of all recorded tracking locations for these wide-ranging species fell within the MPA boundaries — highlighting its effectiveness in protecting highly mobile marine wildlife.

Comparing Large and Smaller MPAs

The research, led by a team from the University of Exeter, Heriot-Watt University, and the Zoological Society of London (ZSL), also assessed the impact of a hypothetical smaller MPA covering 100,000 km². While manta rays (97%) and turtles (94%) would still have most of their movements within protected waters, seabird protection dropped significantly to just 59%, due to their greater travel range.

Expert Perspectives

“Very large Marine Protected Areas (VLMPAs) are seen as essential for meeting international goals, such as the target for 30% protection by 2030,” said Dr Alice Trevail, from the Environment and Sustainability Institute at the University of Exeter’s Penryn Campus in Cornwall.
“However, the conservation value of VLMPAs – defined as anything over 100,000 square kilometres – is debated.
Our results provide clear evidence for the value of the Chagos Archipelago VLMPA for protecting a diverse range of large and mobile marine species.”

Co-author Dr Ruth Dunn, from Heriot-Watt University, added:
“These large animals play a variety of important roles in marine ecosystems. For example, the Chagos Archipelago supports a huge number of seabirds, and the guano (droppings) from these birds help to fertilise coral reefs and other marine species.”

Ecological and Policy Significance

With anticipated changes in sovereignty as the Chagos Archipelago transitions to Mauritian control, the findings carry increased relevance for policymakers. The study not only underscores the current MPA’s importance but also pinpoints critical areas for future long-term protection to sustain the marine megafauna community.

Ernesto Bertarelli, President of the Bertarelli Foundation, which funded the study, remarked:
“Discoveries like this are only possible when scientists from different disciplines work together. By doing so, this team of researchers has shown how truly large Marine Protected Areas can provide vital protection to vulnerable species throughout their lives.”

Key Findings 

• Study location: Chagos Archipelago Marine Protected Area, Indian Ocean.
• MPA size: 640,000 km² — covers 95% of tracked species’ movements.
• Species studied: Hawksbill turtles, reef manta rays, red-footed boobies, brown boobies, and wedge-tailed shearwaters.
• Smaller MPA scenario (100,000 km²):
  • 97% manta rays and 94% turtles still within protected waters.
  • Only 59% of seabirds protected due to larger travel ranges.
• Conservation impact: Strong evidence for the role of Very Large MPAs (VLMPAs) in meeting global biodiversity targets.
• Policy relevance: Highlights need for continued and targeted protection, especially during political transitions.

Original Publication
Authors: Alice M. Trevail, Ruth E. Dunn, Peter Carr, Nicole Esteban, Robin Freeman, Joanna L. Harris, Malcolm A. C. Nicoll, Nia Stephens, Guy M. W. Stevens, Stephen C. Votier, Hannah Wood and Graeme C. Hays.
Journal: Journal of Applied Ecology
DOI: 10.1111/1365-2664.70117
Article Title: Large marine protected areas can encompass movements of diverse megafauna.”
Article Publication Date: 7-Aug-2025