By Peter
A marine pandemic has pushed the ecologically important Diadema africanum sea urchin to the brink of extinction, with some populations in the Canary Islands nearly wiped out, a recent study has revealed.
Since 2021, Diadema africanum populations have plummeted by 99.7% in Tenerife and by 90% around the Madeira archipelago, decimating these vital ecosystem engineers. Researchers warn that similar mass die-offs have also been reported in the Red Sea, Mediterranean, Caribbean, and western Indian Ocean, raising global concerns about the health of marine ecosystems.
Sea Urchins: Guardians of Marine Ecosystems
Sea urchins play a crucial ecological role. Related to starfish, they breathe through their feet and defend themselves with sharp spikes, which also provide shelter for smaller marine creatures. By grazing on algae, Diadema africanum helps maintain healthy coral reefs, promoting biodiversity and supporting marine predators.
In the Caribbean, the loss of sea urchins has already caused coral cover to halve, while algal cover increased by 85%, highlighting the cascading effects on marine habitats.
“What fascinated me is that they change their environment. Like humans, when they are present, they modify their habitat,” said Iván Cano, researcher at the University of La Laguna. “We don’t know the cascading effect this could have on other species.”
Unknown Cause Raises Global Alarm
The exact cause of the pandemic remains uncertain, but scientists suspect human activity may be involved in spreading the disease. Potential transmission pathways include shipping traffic, changes in ocean currents, and abnormal wave activity.
Cano initially traveled to the Canary Islands to study the early life stages of Diadema africanum but discovered insufficient juvenile populations to continue his original research. He shifted focus to investigate the rapid population decline, warning that the ongoing die-offs could have long-term consequences for marine biodiversity.
Marine biologists are calling for urgent conservation measures to protect the remaining sea urchin populations and prevent further disruption to coral reef ecosystems.
