Integration of different methodologies into a Geographic Information System (GIS) to study coralligenous habitat in Calabrian deep waters (South Italy).

A marine biodiversity monitoring project was conducted by ICRAM in the coastal waters of Calabria (South Italy) on board of ICRAM’s research vessel R/V Astrea, by means of a Remotely Operated Vehicle (ROV). The aim of the project was to study the hard bottom macrozoobenthos in the 30- 250 m depth range. The ROV was equipped with an underwater acoustic tracking position system, a digital camera (Nikon D80, 10 megapixel) with underwater strobe (Nikon SB 400), two laser pointers spaced 10 cm apart (used as linear scale) and a three-jaw grabber to take species samples. Multibeam data were collected, before ROV dives to identify and map potentially interesting sites. These data were also used to create two-dimensional digital maps and were integrated with the acoustic tracking data in a Geographic Information System (GIS) in order to have the ROV position georeferenced in real time on a PC screen during the dives. The analysis of the videos collected by the ROV was done in post-process by means of the software ADELIE, developed by Ifremer, and video-clips of the identified species were inserted in the right position (latitude, longitude) on the multibeam three-dimensional maps, previously created by means of a GIS software. Photos of the identified species were also placed on the 3D maps in the right position (latitude, longitude), linking every picture click-time with the time of the acoustic tracking position system. These methodologies allowed us to find and study the coralligenous habitat at depths not reachable in safety by scuba divers equipped with compressed air, trimix or rebreather, and for a very long time. Furthermore, the integration of these tools in order to create georeferenced 3D seascape maps allows a simple representation and interpretation of the real situation respect to traditional 2D maps, also thanks to the possibility of creating animations. This tool is also particularly useful to study spatial distribution of coralligenous biocenosis presence along sub-horizontal or inclined substrata.