The distinctive black dorsal fin of an orca spotted from the Celtic Explorer. Pic: William Hunt

A group of scientists and students aboard an Irish research vessel had the rare pleasure recently of encountering a group of killer whales - properly known as orcas - which are an uncommon sight in Irish waters.

The pod of seven orcas was spotted on Friday by researchers aboard the Marine Institute vessel the R.V. Celtic Explorer, which is currently conducting a week-longsurvey of marine fauna along Ireland's Atlantic margin as part of a programme called Cetaceans on the Frontier.

The orca is a rare sighting in Irish coastal waters. Pic: Joanne O'Brien

The vessel was retrieving acoustic monitoring devices on the Porcupine Bank, off the south-west coast of the country, when the sighting took place.

Marine Institute map showing the Porcupine Bank to the south west of Ireland

According to a blog post, fin whales, common dolphins and other sea life had been seen in the area when at lunchtime on Friday the killer whales made an appearance.

"Nobody would have predicted the events that would unfold after lunch however when at 13:30 the call came over the walkie-talkies of “KILLER WHALES!!!”," wrote Niall Keogh of Birdwatch Ireland.

"Two enormous, black, triangular dorsal fins came looming out of the water together on our starboard side no more than 50m out!

"Needless to say our full attention was now focused on them! The ship was manoeuvred in order to attain photo-ID pics (which now became our top priority) but the whales did us a massive favour and made several passes alongside us at close range allowing for excellent views of the eye masks, dorsal fins and on some occasions, tail fluking!"

The tail fluke of one of the whales. Pic: Joanne O'Brien

The whales were described as a family group, numbering seven in total.

The encounter was described as an "important find" for the Cetaceans on the Frontier survey.

"Killer whales in Irish waters seem to have a real element of unpredictability about them," said Keogh.

"Some of the Marine Mammal Observers present today have many hundreds of observation hours and thousands of at-seas miles under their belt without having encountered killer whales before today, whist for some of the students joining us on the trip for their first time offshore, things could not have worked out better!"

Two orcas with a great shearwater and a fulmar in attendance. Pic: William Hunt

"Whether informed planning or blind luck had anything to do with it still does not detract from how absolutely amazing the 20 minutes we had with these animals this afternoon was. Smiles all round!"

The Cetaceans on the Frontier survey is a collaboration between Galway-Mayo Institute of Technology, the Irish Whale and Dolphin Group and BirdWatch Ireland, and has been running since 2009.

The R.V. Celtic Explorer. Picture: Irish Aer Corps

The survey is supported under the Marine Institute's competitive ship-time scheme, funded through the Marine Research Sub-programme of the National Development Plan 2007-2013, as part of the Sea Change strategy.

Niall Keogh keeps watch for sightings as the sun rises. Picture: Jason McGuirk

Students and scientists aboard the vessel are currently enjoying a feast of marine fauna sightings off the Kerry coast, with fin and pilot whales as well as dolphins a daily feature.

More exotic marine animals have also been spotted, including gigantic ocean sunfish and even a leatherback turtle!

"We've had fantastic weather this time out, which really helps in terms of sightings," Joanne O'Brien of the Marine and Freshwater Research Centre (MFRC) in GMIT, chief scientist on the survey, told breakingnews.ie.

"Our last survey was in January, during the time of the big storms, and we were pretty much blown back to Galway.

"I think the conditions this time around are our reward for that!"

A giant leatherback turtle spotted by the team today (Monday September 22). Pic: William Hunt

Among the researchers on board the Explorer for this survey are five fourth-year students from GMIT enjoying their first offshore trip as part of research for their final-year project.

"They've all been fantastic," O'Brien said. "It's not easy to come out on a ship like this for your first time but they've all mucked in and been great."

Although the sighting of the killer whales has been the highlight of the trip, O'Brien added that the team had another marine mammal on their wishlist - the gigantic blue whale.

"There's been a lot of baleen whale activity in the area and blue whales have been recorded here in the last two or three years," she said.

"But so far we haven't had any luck. It's nearly time to turn back for Galway so we're hoping that the next couple of hours will bring a sighting."

Meanwhile, in between spotting and recording marine wildlife, they also find time for a a bit of fun aboard ship - such as proudly flying the Donegal flag on top of the M6 weather buoy, located hundreds of miles off the west coast (and probably still technically Kerry territory).

The Donegal flag flies proudly on the M6 buoy. Picture: Damien McCallig

Not that it did any good!

(All pictures courtesy Marine Institute/GMIT/IWDG)

H/T: Irish Examiner