Preliminary results of the craniometric characteristics of the Mediterranean Monk Seal population at Cabo Blanco Peninsula (western Sahara-Mauritania)

Abstract

The Mediterranean Monk Seal (Monachus monachus), classified by the International Union for Conservation of Nature (IUCN) as critically endangered, is one of the world’s most endangered marine mammals, with an estimated total population size of 350-450 animals around the world (mainly located on the eastern Mediterranean, Cabo Blanco area, and Desertas Island in Madeira). In the 1990’s there were around 300-400 individuals in Cabo Blanco (Western Sahara-Mauritania), but on 1997 a mass mortality killed two thirds of the population. Currently, about 130 individuals inhabit the Cabo Blanco Peninsula. Only a few studies have been made on the osteometry of the Mediterranean Monk Seal, mostly in the Mediterranean population, where a sexual dimorphism on the adult skull was described. We carried out craniometric measure ments of 46 individuals died on that mass mortality event. For each individual, we took 31 measurements, founding that the mean length of the cranium, condilobasal length, was 28.62 cm, and the mean length of the mandible, from condylar process to cranial part of alveolar (infradental) arch, was 17.26 cm. The goal of the study was to develop a first approach of the craniometric characteristics of the Cabo Blanco population, in order to provide key information for the management of the actual population.