Rob Deaville, CSIP project manager, said the adult male short-beaked common dolphin was believed to be the dolphin sighted at various locations across the Thames in the last few days.
Deaville said the animal had travelled the furthest west up the River Thames for a common dolphin.
He said that in the past 35 years, common dolphin deaths had rarely been reported within the southern North Sea, but were being increasingly recorded, with the “reasonable assumption” that it was due to climate change.
“Historically the North Sea was an alien habitat for this species,” he said.
Deaville said a post-mortem examination would take place on Friday, but the animal showed signs of skin damage from fresh water, and appeared “skinny” and “not in the best condition”.
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