After 'Mimmo' the dolphin started hanging out in Venice's waters in recent months, the city's lagoon has had a new visitor, with the appearance of a monk seal.

The seal was filmed swimming near the Lido mouth that connects the lagoon to the Adriatic Sea on Sunday and the video was published on the 'Pesca in laguna e mare' Facebook page, daily newspaper Il Gazzettino reported.

"It's likely that this specimen came to our waters to explore new areas, perhaps driven by a search for food, given that our coasts are rich in the fish they feed on," said Mauro Bon of Venice's Giancarlo Ligabue Natural History Museum.

"It's also possible that it came from the Croatian coast, where there are large populations of (monk seals)."