The animal was spotted three days earlier off the Italian island of Ponza, in what is hailed as the “first visit” to Italy by a grey whale.
Experts believe the whale seen off the coast of Pozzuoli on Saturday evening and the port of Baia the next morning, is likely the same animal seen off the Pontine Islands the week before.
Regional maritime authorities have dispatched boats to allow for observation of the whale – estimated at eight metres long – while the local coast guard has ordered all ships away from the area to avoid obstructing its journey.
Noting that grey whales live in the north-eastern Pacific Ocean, between California and Alaska, experts from the Punta Campanella Marine Protected Area said “it remains to be understood how and for what reasons the whale finds itself in the Mediterranean”.
“It could be the changing climatic conditions, with the melting of Arctic glaciers, that has caused this incredible migration,” they said.
The experts also said the animal appears “undernourished and very thin”.
The researchers believe that the sighting of a grey whale off the coast of Morocco in March could be the same specimen.
The grey whale is believed to have carried out the longest migration of a marine mammal: 22,000 kilometres.
Grey whales are found regularly in coastal waters of the North Pacific.
Populations of grey whales off the European coast were wiped out before AD 500, perhaps due to whaling, and became extinct in the North Atlantic in the 18th century.
This makes the sighting of a grey whale off Italy an exceptionally rare event, although it is not the first time one was spotted in the Mediterranean: after centuries of no sightings, a grey whale was seen off the coasts of Israel and Spain in 2010.
