Past and present of fucalean diversity in the island of Marettimo, Egadi Islands Marine Protected Area (Central Mediterranean, Italy)

The Egadi Islands Marine Protected Area (MPA) (west of Sicily) is one of the largest MPAs in the Mediterranean Sea. Nevertheless, studies of benthic macroalgae in this MPA are few and quite outdated. The latest study, performed about 20 years ago, documented the disappearance of cold affinity species (mainly Cystoseira s.l. and Sargassum species) in favour of warm affinity ones. In this study, we conducted a visual census activity through snorkelling and scuba dives on the island of Marettimo, and we found a total of 17 Fucales: four belonging to Cystoseira, eight to Ericaria, two to Gongolaria, and three to Sargassum. The obtained data were compared with previous studies conducted in the 1970s and in the early 2000s in the E-MPA reporting data on the Fucales stands to understand the dynamics that have occurred during this period. Five species, not previously reported from the island of Marettimo, were found during this study: Cystoseira cf micheleae, Ericaria barbatula, Ericaria brachycarpa var. claudiae, Gongolaria montagnei var. compressa and Sargassum cf furcatum.