Cialdi Seamount 

The Cialdi Seamount is a 36 km-long N-S oriented structural ridge, located 10 km to the east of the Etruschi Seamount in the northern Tyrrhenian Sea. It shows steep western and eastern slopes, and reaches 340 m depth at its flat top area (Würtz & Rovere, 2015).

The high primary production area, surrounding Cialdi Seamount, is known to support many different shark and ray species (Baino et al., 2010). No previous ROV surveys were conducted in this site.

The BioMount surveys were carried out on the top as well as the northern and southern flanks between 340 m and 591 m depth. The seafloor is dominated by Fe-Mn-encrusted CWCs tanatocoenoses (free or embedded) immobile witnesses of past lush communities as revealed by previous fossils analyses (López Correa et al., 2005).


Solitary scleractinians and decapods inhabit the crevices on the bottom, hardground oases surrounded by biogenic detritus. Sponges, gorgonians and sea urchins are also found in this habitat, but the most striking discovery is a dense forest of Parantipathes sp., a deep red antipatharian species surrounded by clouds of minute mysidiaceans and watched by rockfish and catsharks at over 500m depth. Very few antropic traces are found on this mount.

The catshark Galeus melastomus.The deep gorgonian Bebryce mollis.A deep siphonophoran dancing in the deep.A deep cidarid sea urchin.A colony of Parantipathes sp. surrounded by a cloud of euphausiaceans attracted by lights.