The Sisbiota-mar photoquadrat survey aims to quantify the benthic cover of horizontal reef surfaces using photography and subsequent image analysis, in a manner that is directly comparable across geographies. Our survey method employs 2m2 horizontal surfaces of reef area at 1-7 meters (shallow) and 8-15 meters (deep). At each locality, between one and five reef sites were assessed (but most of them had at least three sampled sites). The 2m2 horizontal surfaces of reef area were at least 2 meters apart and haphazardly selected (avoiding sand patches). On each 2m2 reef area, the benthic community was assessed by a set of five 25x25 cm photoquadrats.