Diadema Updates – Recent Publication January 2023

Diadema Updates – Recent Publication

The 2022 Diadema antillarum die-off event: Comparisons with the 1983-1984 mass mortality (Hylkema et al., 2023)


The 1983-1984 die-off of Diadema antillarum (long-spined sea urchin) across the entire Caribbean had devastating impacts on its coral reefs. As populations of a key reef herbivore were decimated, cascading effects included excess algal growth, increased competition between corals and algae, and reduced coral recruitment. When Diadema were suddenly observed dying again in spring 2022, there was concern for negative consequences of additional ecological stressors on the region’s coral reefs, especially following the catastrophic loss of massive corals due to stony coral tissue loss disease in many locations.

The Diadema Response Network (DRN), which AGRRA is a founding member, has documented the spread of the 2022 die-off with the online  ArcGIS Diadema Tracking map (https://www.agrra.org/sea-urchin-die-off/). Thanks to the collaboration of numerous partners in the region, over 700 reports of healthy, sick, and dying urchins have been submitted from >30 jurisdictions to date; identifying areas affected by the die-off as well as areas not affected.


Map shows Progression of the 2022 D.antillarum die-off in the Caribbean (Figure 1 from Hylkema et al 2023).

Authors: Alwin Hylkema, Kimani Kitson-Walters, Patricia R. Kramer, Joshua T. Patterson, Lynnette Roth, Moriah L.B. Sevier, Maria Vega-Rodriguez, Matthew M. Warham, Stacey M. Williams and Judith C. Lang. January 2023.

Diadema Publications can be found in the Resources section of the AGRRA Diadema Response Network page.

The chronological spread and duration of this new die-off, and descriptions of sick and dying urchins have been presented by Hylkema et al., 2023. The die-off has affected at least 25 jurisdictions in the Caribbean.