Modelling predicted sperm whale habitat in the central Mediterranean Sea: requirement for protection beyond the Pelagos Sanctuary boundaries

Abstract

Abstract Climate change and human activities impacts are considered to be the main causes of sperm whale habitat alteration. Despite the creation of several marine protected areas in the Mediterranean Sea, the sperm whale status remains ‘endangered’. Its spatial distribution has been reported in different areas of the Mediterranean, among them the Pelagos Sanctuary. Various biophysical parameters have been recognized to influence sperm whale distribution depending on the modelling scale. Hence, this study investigates and predicts sperm whale relative occurrence, taking into account the parameters that affect their habitats in the central Mediterranean Sea, inside and beyond the boundaries of the Pelagos Sanctuary. An artificial neural network (ANN) model was used to predict the probability of sperm whale occurrence in the central Mediterranean Sea, for each cell of a 3 × 3 minute grid using a Visual Basic script to interface with GIS software. The algorithm was trained using species presence/absence data and a set of physiographic variables such as depth, slope, distance to shore and magnetic field. Some geographic areas exhibit a consistently high probability of occurrence and may be identified as highly used areas for special management concern. Thus, this work represents a preliminary evaluation of management and conservation effort outside the Pelagos Sanctuary. The map of sperm whale predicted relative presence can be used to mitigate potentially harmful human activities and to support the design and management of marine protected areas, including the delineation of ecologically meaningful boundaries. Copyright © 2013 John Wiley & Sons, Ltd.