Officials are monitoring a seal with black tubing around its neck on Rathlin Island.
The Department of Agriculture, Environment and Rural Affairs (DAERA) said it has been visiting the island off Co Antrim every two weeks to monitor the seal's condition.
The department in Northern Ireland said it is liaising with Exploris Aquarium and Seal Sanctuary in Portaferry, Co Down.
Head Keeper at Exploris Aquarium Euan Morrison said the seal is a female and is "roughly around two or three years old".
Mr Morrison said she is "perfectly healthy" and is "bright and alert".
"Its head and tail are up and it looks nice and fat," Mr Morrison said.
He said Exploris was first alerted about the seal at the start of August but said it might have had the tubing around its neck since May or even longer.
Mr Morrison said intervention measures are difficult to implement without disturbing other seals in the colony.
"It would be lovely to catch it but it isn't straightforward as it is a big animal," Mr Morrison said.
He said it would take five to six people to try to restrain the seal, so they have to wait to see if its condition deteriorates and then intervene.
Mr Morrision added they cannot "dart" the seal because it could disappear in the water and fall asleep.
Cherie Toland from Lurgan, Co Armagh, took a video of the seal while hiking on the island last Saturday afternoon and said it was upsetting to witness the seal in that condition.
"I thought it had happened recently as the seal wasn't emaciated. However, I found out from locals it had been reported three weeks prior to me seeing it," Ms Toland said.
"My first instinct was we needed to try help so I posted footage on Facebook and a couple Rathlin groups in the hope people could advise. I then contacted Seal Rescue Ireland, Exploris Aquarium and British Marine Divers Life Rescue," she said.
DAERA said it is asking members of the public to notify it and its partners, such as Exploris Aquarium, of any further sightings of the seal.
