A dead dolphin was washed up on a Gower beauty spot, tangled up in fishing netting.
The sad sight was witnessed by visitors to Caswell Bay over the weekend.
However, despite being caught up in the fishing equipment, experts say the animal may have died before it became entangled.
It will now be subject to a post mortem to determine the cause of death.
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Rod Penrose, of the Cetacean Strandings Investigation Programme which retrieved the dolphin carcass, said: “I carcass has been recovered, but unfortunately all traces of the fishing gear had been removed from the carcass and the beach.
“Although I’m sure this was done by a well meaning individual or group, it would have been useful to document the type of gear in case it was involved in the entanglement of this female short-beaked common dolphin.
“However, the dolphin may have died from other causes and washed into the net already dead.
“We shall not know until it undergoes a full post-mortem examination at London Zoo”.
Matthew Westfield, Wales s trandings co-ordinator for CISP said: "The dolphin was first reported to me on Sunday around lunchtime.
"The initial pictures showed it wrapped in what looks to be fishing net on a beach at Caswell bay, but it is currently unclear if this is what caused the dolphin to strand.
"As the day went on we got a number of other reports of the dolphin wrapped in netting but just after 3pm I was sent further pictures with no netting. It would seem that some well meaning individuals had removed the netting and disposed of it".
Lauren Eyles, a marine biologist and south west Wales coordinator for the Sea Watch Foundation which monitors whales, dolphins and porpoises around the UK's coastline, added: "It is difficult at this stage to know what might be the cause of death; it could be a number of reasons.
"It looks like quite a healthy dolphin, and it might have come into contact with mircoplastics, but it could also been victim to ghost-fishing, which is when nets have been left in the ocean, or having become lost and the dolphin became tangled.
"They are air-breathing mammals so have to come to the surface to breath like we do, or else they will drown.
"Or there is also bycatch fishing, when fishermen target specific species of fish, but sea mammals get caught up in them.
"There are lots of different ways it might have died, and we won't know until the post mortem is carried out, but having said that plastics and litter could be highly likely.
"It is a world wide, massive problem".
Earlier this summer, a pod of dolphins were caught playfully swimming around the shore at Oxwich, as well as sea lions.
But they have also been discovered lifeless on Swansea 's beaches.
A short-beaked common dolphin became stranded at West Pier last year, and was discovered on the beach near Swansea Marina.
The Cetacean Strandings Investigation Programme (CSIP) records information on all cetaceans, marine turtles and basking sharks that strand around the UK shores each year, and with the investigation of suitable strandings through post-mortem examination.
Anyone does come across a dead Cetacean, marine seal or basking shark should report it to the cetacean strandings line on 0800 652033.