Yellow Sea Fan

Yellow sea fans are the dominant structural feature of the Puerto Colón Wall between 15 and 35 metres, their flattened fan structures oriented perpendicular to the prevailing current to maximise planktonic capture by the polyps that line every branch. As ecosystem engineers they provide structural complexity equivalent to coral heads on tropical reefs, with each colony supporting populations of associated species including Canarian blennies nesting in the base branches, Mediterranean arrow crabs sheltering among the fans, and cryptic nudibranchs grazing on the polyp tissue itself. Their recovery from historical collection for the souvenir trade and net damage from artisanal fisheries is ongoing, and the density of large individuals on this wall suggests several decades of protection from direct disturbance.