A dolphin has been found dead on the bank of the Thames in southwest London.
It comes just days after a dolphin had been seen swimming in the river between Hammersmith Bridge and Putney Bridge on Tuesday.
The mammal, confirmed as an adult male short-beaked common dolphin, was seen lying on the foreshore at Mortlake in Richmond on Thursday, according to the Port of London Authority (PLA).
The Cetacean Strandings Investigation Programme (CSIP), an organisation that coordinates the investigation of all cetaceans, marine turtles and basking sharks that strand around the English coastline, attended the scene.
Representatives from the British Divers Marine Life Rescue, an organisation dedicated to the rescue and well being of all marine animals in distress around the UK, also attended.
It has not been officially confirmed if it was the same dolphin seen earlier in the week.
Back at @ZSLScience after recovering this adult male common dolphin earlier today- live stranded and died at Mortlake in the Thames, #CSIoftheSea exam to follow tomorrow. Many thanks to our friends at @BDMLR and the @TidewayScullers team for all their help today! pic.twitter.com/nD8pVpSolZ
— Rob Deaville (@strandings_man) July 2, 2026
Rob Deaville, a project manager for CSIP, said that it had travelled the furthest west up the River Thames for a common dolphin.
He said that common dolphin deaths had rarely been reported within the southern North Sea in the past 35 years.
However, reports have increased, with the "reasonable assumption" that it was due to climate change.
Mr Deaville told the BBC: "Historically the North Sea was an alien habitat for this species."
He said that the animal showed signs of skin damage from fresh water, and appeared "skinny" and "not in the best condition".
A post-mortem examination will take place on Friday.
A PLA spokesperson said: "Unfortunately, when dolphins are sighted this far up the Thames it can often indicate they are already in distress."
They added: "British Divers Marine Life Rescue have been monitoring the situation and we are working with them, Cetacean Strandings Investigation Programme and other partners to carefully recover the animal and establish what may have happened."
