The crew of a North Sea emergency response and rescue vessel were amazed to see a school of orca whales surround their ship, 155 nautical miles east of Aberdeen.

Chief officer Graeme Hately on the Grampian Protector captured the episode on video, including a mother and baby swimming under the waves. The killer whales can also be seen leaping from the water and swimming alongside the ship.

Graeme said he estimated there were around 30 animals in the vicinity. He and his colleagues believed the orcas were hunting for fish.

“We are all stunned to see so many of them at the one time. There were at least 30. We were completely surrounded by them.

“You can see them thrashing their tails, we think they were trying to trying to corral a shoal of fish.”

Graeme has served aboard the ERRV Grampian Protector, owned by Aberdeen-based North Star Shipping, for the past 11 years. The ship is on permanent standby to support Marathon’s East Brae platform, which can be seen in the foreground. Other platforms nearby include Brae Alpha, Brae Bravo and the BP Miller platform.

Under his YouTube username Bigwavemaster1, Graeme has recorded other spectacular events such a huge wave hitting the ship, which has received over nine million hits on the social media site.

Graeme, who lives in Nottinghamshire, records a video blog for the crew and is always on the look out for unusual happenings.

He said: “I was just about to turn in and get some sleep, but I always the guys that if anything interesting happened, they should give me a shout -and it doesn’t get much more unusual than a school of whales alongside.

“I have a good quality digital camera and I also have a Go-Pro which I threw into the water with a weight and a buoy to see what I could get. The second mate was trying to keep ahead of them.

“I thought the flashing light on the Go Pro might attract them. You can hear them communicating on the underwater footage. To get the mother and baby was just a lucky shot. I was thrilled when I played back the footage.”

“A lot of the guys were on the deck, but everyone was really quiet. I think we were just awestruck. It’s not the first time we’ve seen them, but it is very unusual to see so many at one time.”

He added: “I have worked offshore for 24 years and this is one of the most spectacular sights I have seen.”