Mortalidades masivas de Diadema africanumUna oportunidad para la restauración de los fondos rocosos de Canarias

Zusammenfassung

Two mass mortality events in 2009-2010 and 2018 have decimated the populations ofthe sea urchin Diadema africanum in the Archipelagos ofthe Canaríes and Madeira (Eastern Subtropical Atlantíc).ln these íslands this sea urchin is a key-herbivore controlling the growth ofthe macroalgae in the rocky ecosystems. Resulting of overfishing and ocean wanning, the urchin populations ha ve transfor- med large areas dominated by non-crustose macroalgae in sea urchin barrens. The two mortality events have been due to an amoebiasis, a disease that has devastated the sea urchin populations, reducing 94 to 98% its initial densities. The monito- ring of urchin populations in two islands of the Canary archípelago, La Palma and Tenerife, has revealed a strong change in the rocky ecosystems organization and functioning. Non-crustose macroalgae have benign recovered their distribu- tion and potential abundance, in addition other organisms such as herbivore fishes have also increased their biomass.