Download Predictive habitat modeling of Cold Water Coral Distribution in the

Predictive habitat modeling of Cold Water Coral Distribution in the Bari
Canyon (Adriatic Sea) with Hydrodynamic variables.
Federica Foglini1 Annaëlle BARGAIN2, Lorenzo Angeletti, Davide Bonaldo, Marie-Claire
FABRI2, , Marco Taviani
2
1
LER PAC, IFREMER, La Seyne Sur Mer, France.
ISMAR–CNR, Bologna, Italy.
Madrepora oculata and Lophelia pertusa are the two main species of cold-water coral (CWC) found
in the Mediterranean Canyons. These Hexacoralia (Scleractinia) are important biodiversity hotspots,
providing habitat and resources for many species, including commercial fishes. However, CWC ecosystems
are especially vulnerable (Freiwald, 2004) and suffer from many physical damages, particularly
anthropogenic impacts from fishery activities (Fabri et al. 2014). Therefore, they have been identified as
sensitive habitat, being priority species for management and protection measures by The General Fisheries
Commission foe the Mediterranean (GFCM, 200a). However, the Mediterranean CWC distribution is still
unknown compared to the one in the Atlantic Ocean (Freiwald et al. 2009) and factors controlling their
repartition are still not entirely understood.
The Bari Canyon is located along the South Western Adriatic Margin and represents the main
sediment conduit active since the last glacial interval (Trincardi et al., 2007). It is the main path for the North
Adriatic dense Water cascading and represents the main biodiversity hotspot for CWC habitats in the
Adriatic Sea.
The objective of this study is to combine several parameters to describe the environmental
conditions in favor of CWC settlement: (1) CWC observations, extracted from georeferenced underwater
video films, (2) eco-geographic variables (EGVs) derived from high resolution bathymetry (collected by an
autonomous underwater vehicle), (3) reflectivity from the multibeam (4) hydrodynamic data (based on
ROMS for ocean currents, coupled with SWAN within the COAWST modelling system). Habitat suitability
models have been used to identify the main eco-geographical variables explaining CWC distribution.
Presence-only models (MaxEnt and ENFA) but also presence-absence model (GLMs) have been used and
compared.
The models pointed out slope, rugosity, water density (salinity and temperature) and maximum current to be
the main explaining factors for CWC distribution. These results have been used to produce habitat suitability
maps useful for the assessment of potential habitat extent for deep sea environment also in the framework of
the Marine Strategy framework directive (MSFD).