Mapping of Mediterranean rhodolith beds (RBs) should be focussed on areas of the seafloor with >10% cover of live calcareous red algae for a minimum surface of 500m2, on 1:10000 scale. More detailed scales (at least 1:1000) should be used for monitoring selected RBs, in order to detect significant changes through time. Beside the location and areal extent, the description of a RB that could be provided by non-specialists should include the occurrence of macroscopic sedimentary structures of the seafloor, thickness of live cover, mean percentage cover of live thalli, and dominant morphologies of rhodoliths (unattached branches, pralines or boxwork rhodoliths). For the purpose of ecological status assessment and the evaluation of human-induced impacts, the protocol requires the support of specialists to add details on the assemblage composition
