Sea caves are habitats of great ecological and geological value. This habitat is very specific and important in terms of marine productivity, providing a refuge for several species of fish that use the area as a nursery (such as the Conger Conger conger) and for many marine invertebrates. In Berlengas archipelago there are several sea caves very interesting for marine biodiversity. Because of the frail light that penetrates the caves there are few algae and plants however, sea caves are authentic wildlife refuges, with many species of invertebrates (sea fans) and tunicates covering the stony walls. The unique beauty of these caves attracts many scuba divers to Berlengas. The caves on the bay of “Cova do Sono” in Berlenga Island, or the cave of “Rabo de Asno” in Farilhões are two diving hot-spots.