Abundance and movements of sperm whales in the western Mediterranean basin

Sperm whales in the Mediterranean are classified as ‘Endangered’ by the IUCN. They are apparently isolated from adjacent Atlantic populations, and subject to anthropogenic pressures including interactions with illegal driftnet fisheries, ship strikes, ingestion of debris and underwater noise.Photo-identification data opportunistically collected from the western Mediterranean basin show that individual sperm whales regularly move in excess of 500 km across the western basin, suggesting that this area is occupied by a single population.The best abundance estimate for this region is approximately 400 animals, with confidence intervals between 200 and 1000.Given the mortality levels reported in the literature, this figure suggests that the conservation status of sperm whales in this region is very serious. Immediate priority should be placed both on conducting systematic surveys for abundance estimation and on measures to reduce the mortality associated with driftnet fishing