A grey seal pup who was found dehydrated and underweight at St Brides Bay in Pembrokeshire - following a long 120km journey in the wild from Cornwall in four days - has been released back into the wild.

Affectionately named Muse [after the Devon rock band that hail from Teignmouth] - the seal pup has been cared for by staff at RSPCA West Hatch Wildlife Centre in Taunton, Somerset, for the past few months.

After his rehabilitation he now weighs 41.5kg - nearly tripling in size since he was rescued back in December in Pembrokeshire, after concerns were raised about his health four days earlier when he was spotted in Cornwall.

Muse was released at a location in Devon on Wednesday, April 8 and a video shows him racing down to the water’s edge when he was released from his carrier.

He was released alongside five other seals - who were rescued by British Divers Marine Life Rescue - Jimi Hendrix, Lewis Capaldi, Run DMC, Kate Nash and Oxford Comma (with singers and bands being this year’s theme at the centre).

RSPCA West Hatch Wildlife Supervisor Ryan Walker, said: “It was absolutely wonderful to see Muse along with the group of seals going back to where they belong. They had all been admitted either with injuries, were unwell or were underweight and we have spent the time needed to get them back to full health and at a weight fit for release.

“As always, their success stories are down to a real team effort from the rescuers, all the vets, staff and volunteers at West Hatch and to our supporters who generously help us so we can continue what we do.”

Each seal pup rehabilitated at RSPCA West Hatch can remain in care at the centre for a number of months and during this time the centre will be spending on average £1,400 a week on fish and veterinary care during seal season - which typically runs from September to March.

Muse, a moulted pup, was fully weaned but was found in a thin condition when he was spotted on the rocks at St Brides Bay on December 11.

RSPCA Animal Rescue Officer and Wildlife Officer, Ellie West attended the location, and said she had concerns about him immediately as he was dehydrated, in a thin body condition and with “obvious rolls of skin” that should have been filled with fat/blubber.

She also noticed he had marks on his back, similar to the spray marks put on seals by the RSPCA after they have been assessed, so if there are any further calls or they come into care again some of their history is known.

But Ellie noted that the colour of the marks were different to the usual used in the area so she contacted the British Divers Marine Life Rescue who confirmed they had checked on the seal a few days previously.

Ellie said: “Muse's story is such a fascinating one, and I’m delighted that he has now returned to the wild.

“When I initially assessed him, little did I know that he had travelled such a long way in such a short time. When I spoke with the British Divers Marine Life Rescue they confirmed that the pup was the same one their volunteers had marked four days previously on December 7 at Port Gaverne, North Cornwall.

“He had been very feisty and a borderline weight at that time and he was released. With space in wildlife rehab centres at a real premium for seals, this particular seal was deemed suitable to be given another chance in the wild without intervention.

“However, in the four days after this, he made his way to St Brides Bay, covering a distance of around 120km!

“This is a really long swim for a young pup and during these few days he had lost more weight and now on the Pembrokeshire coastline he was dehydrated and passing some very dark loose faeces. He also had some ulcers in his mouth.”

Ellie removed the pup from the beach and she gave him the immediate care he needed by giving him tube feeds of electrolyte fluids and fish before taking him to RSPCA West Hatch.

Ryan said: “Muse came into the centre underweight and with a possible respiratory infection so he had a course of antibiotics but following the work of Ellie and her team he had self fed the entire time.”

Ryan added: “He's consistently gained weight each week over the past few months showing he can compete well with the other seals for his share of the fish. As of Christmas Eve he had gone up from 16kg on admission to 19kg.

“He paired up well with another seal and moved to our shallow outdoor pools in early January then moved into the main pre-release pool with 11 other seals at the end of February.

“His last weight was measured at 41.5kg - nearly tripling in size since he was picked up on the beach.”

The RSPCA works in partnership with a number of other organisations to come to the aid of seals, and British Divers Marine Life Rescue rescued all of the five seals who were released alongside Muse.

The RSPCA advises that if members of the public spot a seal on a beach that they observe them from a distance and do not approach them. Seals are wild animals and have a nasty bite if they feel threatened. It is also advised people keep dogs on leads on beaches that have seal colonies too.

“It's not unusual to see a dependent seal pup by itself, as their mothers will leave the pups alone very early on in life, feeding in the sea then returning to feed them,” said Ellie.

“If you find a seal pup that looks fit and healthy and shows no signs of distress, monitor it first from a safe distance for 24 hours.

“However, if the mother doesn’t return after 24 hours or the pup appears distressed, injured or unwell, or is on a busy public beach, our emergency line can be reached. Please always stay at a safe distance and keep dogs well away - seals can have a very nasty bite if threatened.”

Ellie added that in west Wales it is generally grey seals they see (rather than common seals) and grey seal pups are a little easier to tell if they are of an unweaned age.

“If they have a long white coat of fur (lanugo) they are most likely still dependent on mum and likely still suckling,” said Ellie.

“It’s when they lose this long white fur they are at a weaned stage. A large majority of seal pups we get called to are in fact weaned from their mothers and have lost a significant amount of weight where they have not mastered the act of feeding and fending for themselves well enough, these pups quite often need to be rescued for assessment and rehabilitation due to being malnourished.

“Our main message is if they look in distress or unwell please call it in,” she added.

There is more information on the RSPCA website about what to do if you see a seal or pup on the beach alone.