The challenge of habitat modelling for threatened low density species using heterogeneous data : the case of Cuvier’s beaked whales in the Mediterranean

摘要: Abstract The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to number conservation threats, in particular underwater noise. It also cryptic at surface relatively rare, so obtain robust knowledge on distribution abundance presents unique challenges. Here we use multiplatform multiyear survey data analyse this species across Sea. We novel approach combining heterogeneous gathered with different methods single density index for region. A total 594,996 km effort 507 sightings Cuvier’s whales, 1990 2016, were pooled together 24 sources. Data divided into twelve major groups according platform height, speed sea state. Both availability bias effective strip width calculated available perpendicular distance data. This was extrapolated rest each groups. Habitat preference models fitted GAM framework using counts as response variable searched area an offset. Depth, coefficient variation depth, longitude marine regions (as defined by International Hydrographic Organization) identified important predictors. Predicted per grid cell multiplied mean group size prediction animals. 5799 (CV = 24.0%) animals estimated whole basin. Alboran Sea, Ligurian Hellenic Trench, southern Adriatic Sea eastern Ionian being main hot spots urge that relevant stakeholders incorporate information planning execution high risk activities these high-risk areas.