Hidden pandemic is quietly wiping out sea urchins globally-Here is what scientists found

Sea urchins in the Canary Islands and Madeira through 2022 and 2023 (Image: Cano/Lorenzo-Morales/Bronstein/Sangil and Hernández)

The once-abundant sea urchins of the Canary Islands and Madeira are disappearing.

Scientists warn this “pandemic” could reshape marine ecosystems deeply. Recent studies reveal population crashes of up to 99.7% in some reefs.

What Happened To Sea Urchins?

Populations of Diadema africanum collapsed between 2022 and 2023. The surveys recorded almost total disappearance in Tenerife and large losses elsewhere. Follow-up surveys from 2023–2025 confirmed ongoing population deficits. Larval traps in 2023–2024 showed almost no new juvenile recruitment.

Scientists suspect the die-off event may be part of a wider timeline. Thousands of urchins died on the seafloor, showing morbid signs first. The event signals a major ecological crisis for regional reefs.

Who conducted this study?

The study on sea urchin die-off was led by Iván Cano. He is affiliated with the University of La Laguna, Tenerife in Spain. Researchers focused on Diadema africanum populations across 76 reef sites. Surveys were conducted between 2022 and 2025 in the Canary Islands. This study was published in Frontiers in Marine Science.

Is someone affected by Die-Off?

Yes, the die-off affected 76 reef sites in the Canary Islands. Tenerife, La Palma, and surrounding islands suffered the largest losses. Nearby Madeira also showed significant population declines in 2023 surveys. Reports suggest the pandemic may extend to other Atlantic reefs. Global implications are possible if similar events continue elsewhere.

Why Are Sea Urchins Dying?

Exact cause remains unknown. The researchers aim to understand whether a global pandemic is underway. Loss of urchins could destabilize entire reef ecosystems quickly.

“We don’t yet know for certain which pathogen is causing these die-offs. Mass mortality events of Diadema elsewhere in the world have been linked to scuticociliate ciliates in the genus Philaster, a kind of single-celled parasitic organisms,” said Cano.

What Future actions Are Underway?

The marine biologists are monitoring surviving sea urchin populations carefully. They study larval recruitment to understand future population recovery. The die-off highlights the fragile balance of marine ecosystems.

Scientists warn that without urgent intervention the ecosystems will face long-term collapse. Ongoing research and conservation offer hope for reef recovery and resilience.