The public has been warned to keep away from an injured dolphin that was filmed dancing and playing with swimmers off the coast of Dorset earlier this month.

The Marine Management Organisation (MMO), a government-backed agency responsible for England’s seas, said it was “increasingly concerned about a lone dolphin spotted in Lyme Bay, Dorset, following multiple potential marine wildlife disturbance offences observed online and shared on social media”.

The post showed an image of a bottlenose dolphin, who has been nicknamed Reggie, that appeared to have a gash on the right side of its torso beneath its dorsal fin, which it said was not part of a pod.

Reggie with injuries. Photograph: Marine Management Organisation

The dolphin appeared in a viral clip in early August in the bay alongside Lynda MacDonald, her partner, her son and his girlfriend as they were out for a swim. The dolphin bobbed in and out of the water, playfully engaging them and receiving belly rubs.

Though the interaction appeared jovial and harmless, the MMO has issued a strict warning that such encounters “can harm dolphins leading to injury, death, or aggression”, urging the public to keep its distance.

The MMO said the public should “never swim with, touch, feed, or approach dolphins. If a dolphin approaches you, calmly leave the area.”

“Human interaction can cause dolphins to lose their natural wariness, leading to injury or even death,” the agency added. “Disturbed dolphins are also known to become aggressive toward people.

“Dolphins may seem friendly, but they are wild animals. The dolphin in Lyme Bay has already been injured by a suspected boat propeller,” the MMO said. “Let’s protect them by keeping our distance and please share this message to respect their space.”

Whale and Dolphin Conservation, a charity dedicated to protecting wild dolphins and whales, says dolphins can be disturbed not only by jetskis and motorboats but any intrusive human interaction. When people encounter dolphins, the WDC advises keeping a safe distance, leaving after about 15 minutes, and ensuring no more than two boats are within 300 metres of a group of dolphins.

According to the Joint Nature Conservation Committee, 28 different species of whales, dolphins and porpoises have been recorded in UK waters – including four types of dolphin: bottlenose, common, Risso’s and white-beaked. There are an estimated 700 bottlenose dolphins living off the UK’s shores.

They can be encountered fairly regularly off the British coast, potentially coming into contact with swimmers or people sailing, interactions that can cause the animals harm.