Background.

Corals play a fundamental role in reef structure and function because of their ability to deposit calcium carbonate and contribute to the formation of complex three-dimensional structures. However, the functioning potential of a reef community, in terms of its building capacity, is affected by the relative abundance of coral species on the reef.

Objectives.

Evaluate the physical functionality of coral reefs at six sites in the Parque Nacional Zona Marina del Archipiélago Espíritu Santo (PNZMAES).

Methods.

The Reef Functional Index (RFI) was implemented as a metric of physical functionality; this tool considers the calcification rate, structural complexity, and abundance of coral species at each site.

Results.

Las Navajas and San Gabriel sites had the highest coral cover, with 74.72 % and 60.14 %, respectively, while La Ballena was the site with the lowest coral cover (6.77 %). In terms of IFA, the sites with the highest index were Las Navajas (0.68) and San Gabriel (0.65), dominated by Pocillopora meandrina and Pocillopora verrucosa corals, respectively. The site with the lowest IFA was La Ballena (0.35), with Pocillopora verrucosa being the predominant coral. Coral species of the genus Pocillopora were predominant in all sites and contributed the most to the Reef Function Index.

Conclusions.

The Reef Function Index helped to complement the information on the coral assemblage in the PNZMAES and to understand the performance of coral species in the reef functioning of the Mexican Pacific.