Temperature data of the 2022 MHW and underwater pictures of impacts on bath sponge populations

July-to-August seawater temperature recorded at 18 m depth at the “3PP” station, La Ciotat, near Marseille, South of France (43.163°N; 5.599°E) using <em>in situ</em> autonomous sensors during the 2022 MHW, in the two previous years (grey dotted lines), and during the reference 2003 MHW (orange dotted line). Only one record per day is shown; IMG 1467: Two living sponge species, <em>Ircinia oros</em> and the bath sponge <em>Spongia officinalis</em>, the latter with necrotic spots on its surface (September 7, 2022) - Author Thierry Pérez IMG 1688: The same two sponges after five days (September 12, 2022), <em>S. officinalis</em> is dying, covered by a white bacterial veil. Author Thierry Pérez P9216598: A once rich and healthy population of <em>S. officinalis</em> at 10 m depth, September 21, 2022; Arrows point to <em>S. officinalis</em> dead skeletons left attached to the rocky wall; Author Pierre Chevaldonné