Deep-sea sponge-dominated communities are complex habitats considered hotspots
of biodiversity and ecosystem functioning. They are classified as Vulnerable Marine
Ecosystem and are listed as threatened or declining as a result of anthropogenic
activities. Yet, studies into the distribution, community structure and composition of
these habitats are scarce, hampering the development of appropriate management
measures to ensure their conservation. In this study we describe a diverse benthic
community, dominated by a lithistid sponge, found in two geomorphological features
of important conservation status —Le Danois Bank and El Corbiro Canyon— of the
Cantabrian Sea. Based on the analyses of visual transects using a photogrammetric
towed vehicle and samples collected by rock dredge, we characterize the habitat and
the associated community in detail. This deep-sea sponge aggregation was found on
bedrock. It is dominated by one lithistid sponge, Neoschrammeniella aff. bowerbankii
(0.2 ind./m2) and further composed of various sponge species as well as of other benthic
invertebrates such as cnidarians, bryozoans and crustaceans. Using a non-invasive
methodology (SfM – Structure from Motion) and empirical relationships of individuals
size and biomass/volume obtained in laboratory for N. aff. bowerbankii, we were able
to estimate a total biomass of 41 kg and volume of 39 l of this species in the surveyed
area. This approach allows a fine tune methodology for estimating biomass and volume
by image-based-observed area avoiding destructive techniques for this species.Postprin