Fears grow for 'lethargic' dolphin spotted swimming in the Thames as expert says aquatic mammal 'shouldn't really be this far up the river or alone'

Concerns are mounting about a 'lethargic' dolphin which has been spotted swimming in the Thames.  

A dolphin has been spotted swimming in the Thames near Bermondsey in southeast London and a further dolphin sighting was reported near Putney in the southwest of the city.

Whilst it remains unclear if both sightings are of the same dolphin, experts have voiced concerns that the marine animal spotted in Putney looked 'disoriented and lethargic.'  

In a video, shared on social media, a dolphin can be seen swimming along the river near the Angel Pub in Bermondsey. 

The dolphin's  fin can be seen cutting through the waves of the River Thames before it comes up for air giving passersby a clear view of the animal before it disappears under the water once again. 

The passerby who filmed the creature on Wednesday evening said: My friend turned to me and said "I can see a fin". 

'It was quite exciting - everyone was looking over at the river and everyone was in pure shock.' 

Yesterday, there were further sightings of a dolphin further up the Thames.  

The marine animal, which has been nicknamed Jo Jo was spotted breaching the water just west of Putney Bridge at around midday yesterday by a group of rowers. 

Marine mammal medics from the British Divers Marine Life Rescue (BDMLR) are monitoring the dolphin in case it becomes stranded at any point.

Mary Tester, Thames Area Coordinator at the BDMLR in a video posted to X, said: 'It’s on its own, which is extremely rare, and it looks extremely disoriented and pretty lethargic. 

'So it’s potentially swam up the river, maybe gotten lost, and doesn’t have the energy to swim back where it needs to go.' 

She added that this year three dolphins have travelled up the Thames and into London and tragically all of them have died. 

Mike Benson, head of rowing at Barn Elms Boat House, opposite Fulham's Craven Cottage stadium, spied the common dolphin from his office and rushed out on the water to get a closer look.

The 31-year-old, who lives in Bloomsbury in central London, said: 'I could hear some of the kids saying, "What's that?".

'When I went outside I realised it was a dolphin. We were trying to slow everyone down when passing it so it wouldn't become too distressed, but at that point everyone was more interested to see what was going on.

'It isn't every day you see a dolphin in the Thames.

'It would surface every few seconds, but I'm not sure if that's normal because I rarely see dolphins here.

'It went downriver towards Putney for a bit and came back around 4pm.

'We think it must be lost and must be having a horrible time.'

It is unclear if both sightings are of the same dolphin but, conservationists say seeing the dolphin as far up the Thames as Putney was a 'worrying' sign.

Though he frequently sees seals on the river, Mr Benson added that the last time he saw a dolphin back in 2018, the animal didn't survive.

'We quite often get seals up this far,' he said.

'In 2018 another dolphin swam right under our boat, which was amazing.

'But it was found dead a week later so I'm a bit pessimistic about this one's chances.'

The sighting of the common dolphin comes during the 2024 National Whale and Dolphin Watch event, organised by the Sea Watch Foundation (SWF), which involves thousands of volunteers around the UK between July 26 and August 4.

The event has already revealed a striking biodiversity of Britain's whales, dolphins, and porpoises.

Common dolphins are identified by an hourglass shape along the side of the body and their yellow and grey colouring.

They are typically seen in open water in large numbers, are one of the UK's most sociable dolphins and are often seen performing acrobatics - leaping out of the water and breaching at high speeds.

Although an offshore species, the mammals will venture into shallower coastal waters to feed; working together as a pod to herd prey into a 'bait-ball'.

SWF outreach officer Claudia Afeltra explained: 'Over the last week, we have had many common dolphin sightings - however none quite like this.

'These animals are open water, offshore marine mammals, rarely seen close to the shore.

'Reports of dolphins in the River Thames are becoming more prevalent, and although exciting to onlookers, this is very worrying.

'With this concerning sighting, we encourage all to submit any marine mammal sightings through our app, so we can better understand UK populations and can hopefully protect our species more to prevent unusual cases like this happening again.

'This dolphin will continue to be monitored, and, hopefully, will find its' way back to the open water.'