A deadly marine pandemic is wiping out sea urchins in large numbers. Since 2021, the Diadema africanum species in the Canary Islands has faced almost total extinction. In Tenerife, their numbers have dropped by 99.7 percent. Near the Madeira archipelago, the population is down by 90 percent. Similar massive deaths are also seen in sea urchin species from the Red Sea, Mediterranean, Caribbean, and western Indian Ocean. Iván Cano, a researcher from the University of La Laguna, calls this situation "really, really concerning." He said, "We are talking about the disappearance of several species in a really short time." Sea urchins play a vital role in the ocean. They breathe through their feet and use their spikes for protection. These spikes also shelter smaller sea creatures. Known as "ecosystem engineers," they control algae growth, which helps coral survive. Healthy coral reefs are homes to thousands of marine species. In Caribbean reefs, losing sea urchins led to coral cover halving and algae increasing by 85 percent. Cano said, "What fascinated me in the first place about this species is that they change their environment. Like humans, when they are present, they modify their habitat." He warned, "We don’t know the cascading effect that this could have in other species." The cause of the disease is still unknown. But Cano believes humans might be involved in spreading it. Possible causes include shipping, changes in ocean currents, and unusual wave activity. Cano originally came to the Canary Islands to study young urchins but found too few to research. This led him to change his focus to study the rapid population decline. The Diadema genus is the most widespread and ecologically important sea urchin family in tropical waters worldwide. Only a few spots remain unaffected by the outbreak. Cano said, "We aren’t yet sure how this pandemic will evolve. So far, it seems not to have spread to other populations in Southeast Asia and Australia, which is good news – but we cannot rule out the possibility that the disease will reappear and potentially spread further."