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.

Connectivity patterns of bottlenose dolphins (Tursiops truncatus) in the north-east Mediterranean: implications for local conservation.

“…Our study con rms the occurrence of such individuals for the Gulf of Trieste at least, where two individuals (a male and a female) identi ed as having pure Ambracia ancestry, were only seen in the Gulf of Trieste for a limited period of time. The occurrence of such ' oaters' in the region is also supported by recent records of long-distance movements of one individual photo-identi ed in the Gulf of Trieste, which was also previously observed in the Tyrrhenian Sea and subsequently in the Ligurian Sea (Genov et al 2022). Conversely, all individuals that were biopsied and known to exhibit high long-term site-delity, were identi ed as native to the area.…”

Northern Range Expansion of California Coastal Bottlenose Dolphins (Tursiops truncatus)

“…The northernmost coastal bottlenose dolphin sightings in Washington State, where occurrences of this species are rare (Ferrero & Tsunoda, 1989), establish a new distance record for coastal bottlenose dolphins, based on a coastal range of 2,500 km from San Diego to Puget Sound. This exceeds the distance records of photo-identified coastal bottlenose dolphins reported in European waters of 1,076 km (Wood, 1998), 1,277 km (Robinson et al, 2012), and 2,053 km (Genov et al, 2022). By comparison, the offshore ecotype of bottlenose dolphin has exhibited movements of up to 4,200 km in the Gulf of Mexico (Wells et al, 1999).…”

Mitochondrial Variation of Bottlenose Dolphins (Tursiops truncatus) from the Canary Islands Suggests a Key Population for Conservation with High Connectivity within the North-East Atlantic Ocean

“…The lack of genetic structure with pelagic populations, the deep bathymetry of the islands, and the high levels of haplotypic diversity support the hypothesis that bottlenose dolphins from the Canary Islands are part of a large oceanic population in the North-East Atlantic [ 18 , 20 ]. This connectivity among populations could be maintained by the high dispersal capacity of the species [ 35 , 48 , 49 ] and adaptations to deep oceanic environments [ 21 ]. However, one low but significant value in terms of genetic structure ( F st = 0.057, p < 0.001) was found between the Canary Islands and pelagic Mediterranean (but not the Φ st value) ( Table 3 ).…”