The longest recorded movement of an inshore common bottlenose dolphin (Tursiops truncatus)

Abstract

Information on movements and connectivity among populations of animals is important for the delineation of units to conserve, so that demographic parameters, such as abundance, fecundity and mortality, can be placed in an appropriate population and conservation context. Common bottlenose dolphins (Tursiops truncatus) are often considered relatively ‘resident’ and demonstrating strong site fidelity to specific areas. However, this perception may partly be an artefact of the distribution and ‘habitat use’ of cetacean researchers, rather than animals themselves, and bottlenose dolphins have been shown to be capable of substantial movements, often in relatively short periods of time. Here, we report on two long-distance movements of a common bottlenose dolphin within the Mediterranean Sea, across the Tyrrhenian, Ionian and Adriatic Seas, and subsequently back across all three seas to Ligurian Sea, making these the two longest recorded movement for this species in the Mediterranean Sea to date and some of the longest in the world. We also review published records of long-distance movements in this species worldwide. This study highlights the utility of photo-identification and the importance of regional data sharing. We argue that photo-identification comparisons are always worthwhile and the results are informative regardless of the presence or absence of matches, especially with the ongoing advances in automated matching software.