Overview
- Surveys at 76 sites from 2022 to 2025 document archipelago-wide crashes in Diadema africanum, including a 99.7% decline on Tenerife and 74% on La Palma since 2021, with several populations nearing local extinction.
- A second mortality wave in 2023 followed the initial 2022 die-off, unlike the 2008 and 2018 events that were followed by partial rebounds.
- Larval traps in September 2023 captured negligible larvae and January 2024 checks found no early juveniles on eastern Tenerife, pointing to a breakdown in reproduction and recruitment.
- The pathogen remains unconfirmed; past die-offs implicated Philaster-like ciliates or amoebae, and researchers cite unverified spread via currents, shipping or unusual wave activity.
- Parallel die-offs of Diadema species were reported across the Caribbean, Mediterranean, Red Sea, the Sea of Oman and the western Indian Ocean, while Southeast Asia and Australia have not reported similar losses to date.