A pod of orcas or killer whales has appeared in the harbour at Strangford Lough in County Down on Friday
It may be unusual, but according to a local skipper, it is not unheard of.
Richard Connor from Causeway Boats said that it was the third time he had seen them in 22 years of skippering.
Biologist Suzanne Beck from the Agri-Food and Biosciences Institute said the group that are in the lough are part of the west coast community and may be seen a few times a year.
"Usually they might travel on round the coast and the guys in the Hebrides might get a sighting and later they may travel right round Ireland, so you do hear of them every so often," she told BBC News NI.
Still, she said it is an "exciting sighting to see".
"I have only seen them once in Northern Ireland and this is my day job," she added.
"They aren't migrating at the moment.
"We know little about them but I would say they just have a wider range and travel round the British Isles searching for food.
"They're just doing this circuit around us the whole time and it's only when they come close to the coast that we're getting these lucky sightings," she said.
"Killer whales are a really cosmopolitan species," she said.
"They are found in all waters around the world - Antarctica and the Tropics. They're very adaptable."
She said they would not usually be on the coast.
"I would have been concerned if they kept travelling up through the lough but they could have come in to chase a seal or been interested in different noises."
Orcas are the largest member of the dolphin family.
One of the orcas sighted is known to conservationists as John Coe.
Iain McCarthy came down with his children, Cohen, Harris and Ada to see the sight.
It was a dream come true for six-year-old Harris who is "obsessed with whales".
The family was out delivering shopping to an auntie when they got wind it was happening from the Irish Whale and Dolphin Group NI's Facebook page and decided to take a quick detour.
'What a treat'
"When we arrived they were on the turn back and there were three boats near them," he said.
"I was concerned that it could turn into an awkward situation if they didn't find their way out through the narrows but they seemed to make their way back fairly comfortably".
He said the three boats out with them "did a good job of holding back".
He described it as an "incredible still night on the lough".
"There was quite a crowd there and it was funny watching everyone excited watching while observing social distancing," he said.
"It was a stunning night and what a treat," he added.
So what should people do if they see a an orca?
"Respect them and keep your distance. If you're in a boat let the animal approach you. Do not speed off towards them," said Suzanne Beck.
"It's important for the public to get involved and track these animals as it's just too expensive to get on a boat for days and search for them," she added.