People may soon find out what Benny the Beluga sounds like as experts plan to record him as he continues to stay in the River Thames.

The whale, which was first spotted off Gravesend on Tuesday, September 25, has been delighting the crowds and media since it arrived.

The mammal has been spotted many times between Cliffe and Shorne Marshes and has even made some friends when he was joined by two porpoises which were seen with him last weekend.

A joint statement from the British Divers Marine Life Rescue (BDMLR) organisation and the Port of London Authority, has revealed the organisations plan place hydrophone equipment in the water to record its sounds to see if that will help them assess if it is happy and feeding and analyse its behaviour.

Mark Stevens, director of BDMLR said: "The beluga whale continues to be highly mobile, providing limited sightings and swimming strongly and from what we can tell, it is exhibiting normal foraging.

"The sex and age are unknown but improved estimates of length now put it at around 3.5 metres, about eleven feet long."

The organisations have also been in contact with whale experts to help them assess if the animal is well.

Mr Stevens, of Wigmore, added: "Discussions have been held this week with whale experts and relevant agencies to share information and assess possible scenarios.

"Beluga researchers and other experts abroad have been consulted and we will take into consideration their advice and knowledge of this enigmatic species.

"It is planned to place hydrophone equipment in the water this week to record the whale sounds so that experts can then analyse its behaviour. This may help confirm it is feeding.

"The whale’s welfare is our shared priority and we are continuing to observe and protect it."

The public are also being reminded not to take boats out or get close to the whale or even fly a drone over it.

Mr Stevens added: "The safety of the public is also paramount.

"The restriction on boat traffic in the local area remains in force.

"We continue to ask that members of the public do not attempt to enter the water or bring boats or small craft close to the whale or overfly it using drones."

Belugas are also called white whales, and their unusual colour makes them one of the most familiar and easily distinguishable of all the whales.

Calves are born grey or even brown and only fade to white as they become sexually mature around five years of age.

Belugas generally live together in small groups known as pods. They are social animals and very vocal communicators.