A molecular approach to unveil micropredators of sea urchin juveniles in Mediterranean rocky reefs

Alberto Sutera 
Istituto di Bioscienze e BioRisorse -

October 09, 2024 (11:30-12:30)
Webinar Link: https://teams.microsoft.com/meet/332355660434?p=ts6zVVwvpfU9KqIqpq

Abstract: Rocky reefs can alternate two distinct stable conditions: productive algal forests, characterized by high biodiversity, and barren zones dominated by overgrazing sea urchins. Sea urchins, abundant in impoverished states, are generally considered responsible for maintaining this status. In the post- settlement phase, predation of sea urchins may play a crucial role in controlling their population density. However, the small size of both predators and prey makes it difficult to observe these events in the field. We developed specific primers and tested for the detection of mitochondrial DNA (mtDNA) of juvenile Mediterranean sea urchins Paracentrotus lividus and Arbacia lixula on degraded samples. The amplification of urchin DNA in 360 predators collected in algal forests during a sea urchin colonization suggests recent predation events. The results confirm that micropredation plays a significant role in controlling urchin populations, contributing to the maintenance of algal forests in temperate reefs