The basking shark, about seven metres long, was spotted off Faro Island on Saturday, during a leisurely boat trip being enjoyed by a group of friends during the recent spring-like weather.

The animal is the second largest living shark in the world, after the whale shark, and one of three plankton-eating shark species, along with the whale shark and megamouth shark.

Adults typically reach 6–8 metres in length and are usually greyish-brown, with mottled skin.

Newspaper Correio da Manhã reported that the shark spotted off Faro island was “almost the size of the boat” in which the person who filmed it was travelling, at about seven metres.

Marine biologist Élio Vicente explained that the basking shark is “totally harmless to humans” and that “it is a natural and regular presence” in the waters of the sea off the Algarve coast.

Also on Saturday, another ‘giant of the seas’ was sighted on the same coast, albeit in a different location.

A dwarf whale was spotted off the lighthouse of Alfanzina, near Carvoeiro, in the municipality of Lagoa.

The mammal was sighted during a tourist boat trip aboard a whale-watching vessel and by coastal hikers.

The captain of the boat estimated that the whale was at least “seven or eight metres long”.

Biologist Élio Vicente explained that it is also normal for dwarf whales to pass along the Algarve coast, but stressed that “it is not easy to spot them”.