Terradas, Marc, Pena-Martín, Carolina, Valverde Urrea, Miguel, Gran García, Alicia, Blanco Murillo, Fabio, Leyva, Laura, Abellán Gallardo, Eleuterio, Beresaluze, Esther, Izquierdo Muñoz, Andrés, Del-Pilar-Ruso, Yoana, Aguilar Escribano, Javier, Fernández-Torquemada, Yolanda An outbreak of the invasive macroalgae Rugulopteryx okamurae in Alicante Bay and its colonization on dead Posidonia oceanica matte Aquatic Botany. 2023, 189: 103706. https://doi.org/10.1016/j.aquabot.2023.103706 URI: http://hdl.handle.net/10045/136838 DOI: 10.1016/j.aquabot.2023.103706 ISSN: 0304-3770 (Print) Abstract: We report the first occurrence of Rugulopteryx okamurae in Alicante Bay, the northernmost location in the Iberian Mediterranean where this species was detected. Collected specimens were studied using a morphological and molecular approach. A rapid assessment survey was conducted to assess its presence and abundance in the nearest beach-cast and infralittoral areas. The highest abundance was found over dead P. oceanica matte, occupying an important extension in the bay. We found detached fragments of R. okamurae dispersed by local hydrodynamics, accumulating on some tourist beaches in the region. The potential suitability of the Mediterranean for its spread necessitates monitoring programs to study its variation over time and potential impacts on native biota. Keywords:Exotic species, Non-indigenous macroalgae, Rugulopteryx okamurae, Mediterranean sea, Dead Posidonia oceanica matte, Alicante Bay Elsevier info:eu-repo/semantics/article