An international team of marine scientists from the United Kingdom, Slovenia and Italy has documented the longest recorded movement in an inshore common bottlenose dolphin (Tursiops truncatus) — an incredible journey of 2,053 km (1,276 miles).
Prešeren with Slovenia’s highest mountain Triglav in the background. Image credit: Genov et al., doi: 10.1007/s42991-022-00316-5.
On February 8, 2020, University of St Andrews researcher Tilen Genov and colleagues photographed a bottlenose dolphin off the town of Piran, Slovenia, in the Gulf of Trieste, northern Adriatic Sea.
The scientists named it Prešeren, due to the fact it was spotted on Prešeren Day, a Slovenian national holiday dedicated to poet France Prešeren.
On March 10, Prešeren was seen again, this time alone, about 50-100 m (164-328 feet) from cape Madona, Piran, where he engaged in surface feeding activities.
The following year, Genov by chance attended an online talk by an Italian colleague and spotted a fin he recognized in one of the photographs.
After a careful examination of all available photographs, the researchers jointly determined beyond doubt that this was the same dolphin, which was originally called Lino by Italian researchers.
Prešeren had to travel at least 1,251 km (777 miles) to get to Slovenia from the Tyrrhenian Sea, north of Sicily, breaking all the existing Mediterranean records, and most world records too.
But the surprises didn’t end there. After they presented their preliminary results at an online international conference, the authors were contacted by Italian researchers who study dolphins in the Ligurian Sea.
They had photographed the same dolphin as well, just six months after he was observed off Piran.
This time Prešeren had to travel a minimum of 2,053 km, which is the longest recorded movement in a so-called inshore ecotype of bottlenose dolphins, and the second longest for the species overall.
“Bottlenose dolphins are generally thought of as a relatively resident species, with strong fidelity to their home area,” Genov said.
“This is mostly true, but our new findings, together with a review of the existing literature that we carried out, show that this species is much more mobile than we previously thought.”
“This is important in relation to gene flow among populations, which is crucial in the long-term conservation of this species, but it also demonstrates the importance of international collaboration in conserving biodiversity.”
“Such findings contribute to a better understanding of species, which indirectly leads to a better understanding of marine ecosystems.”
The team’s work appears in the journal Mammalian Biology.
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T. Genov et al. The longest recorded movement of an inshore common bottlenose dolphin (Tursiops truncatus). Mamm Biol, published online December 13, 2022; doi: 10.1007/s42991-022-00316-5
