A video of what appears to be a blue shark spotted in the water between Żurrieq and Filfla has been uploaded on social media. 

The shark is seen circling a jet ski with its much feared fin at one point appearing above water. 

"Am no marine expert, but, that looks like a shark to me," wrote Elian Mallia, who posted the clip on Facebook.

But marine expert Alan Deidun said there was no cause for alarm since the fish appears to be the harmless blue shark, which is not uncommon in the central Mediterranean. 

"The blue fin is actually a protected shark nowadays since it used to be over-fished," Dr Deidun said.

Known for their torpedo shaped figure, the shark can reach up to four metres in length and weight up to 205 kilos.