An outbreak of the bald sea urchin disease was detected in 2003 in the coast off Tenerife (Canary Islands, Northeastern Atlantic). The disease affected intertidal populations of the sea urchin Paracentrotus lividus. The mortality event was linked with highest sea surface temperatures (SST) and low wave heights (calm sea conditions). The study carried out by BIOECOMAC constitutes the first record of a mortality event affecting any sea urchin at subtropical latitudes. P. lividus is a temperate species in this area, where it is living at its southernmost geographical limit, constituting a border species. In this context, this disease outbreak and mortality event could be a further example of how predicted changes in ocean temperature can lead to an increased frequency of disease events in sea urchins, as well as in other marine organisms, with the potential to modify their actual distribution.