By John Balson @JJBalson
Scroll down for the full story
Videographer / Director: Paul Slater & Don Shellhammer
Producer: John Balson, Nick Johnson
Editor: Joshua Douglas
Diving instructor Paul Slater, 54, was on a group trip off the coast of Costa Rica when they spotted the 16ft giant caught up in a net.
With help from American Don Shellhammer and their dive master, they swam up behind and used knives to unpin it from the line.
Although it was scared at first and swam away they said it eventually slowed to a stop so they could release it.
They then watched in amazement as it finally broke loose and began to swim around them in barrel rolls in what looked like a gesture of thanks.
Paul, who is originally from Leeds but now lives in New Orleans, said: "It was a wonderful heartwarming event that we all cherished in being able to be involved in. I sincerely believe the display was a thank-you to us."
The rescue unfolded on May 17 off Cocos Island, about 550km off the Pacific Coast of Costa Rica.
The remote island is a protected marine sanctuary and popular among divers searching for encounters with rays, sharks and dolphins.
It is believed to have been the inspiration for the fictional setting of Jurassic Park - although no filming ever took place there.
Recalling the manta ray rescue, Paul said: "I saw a giant manta ray swimming above me.
"I approached the animal and immediately noticed it was snared in a commercial fishing line around its body and dragging at least 200ft more behind it.
"I was shooting GoPro video at the time and the dive master and I approached the animal from behind, deciding originally to cut the trailing line some 20ft behind the animal.
"We made a first cut of the line around the body, but he was pretty spooked and swam off.
"I believe he then realised we were there to help and it circled back around, we came back to him and proceeded to cut the remaining line from him and free him.
"The manta stopped swimming completely so we could work on him. It clearly knew we were trying to help it.
"After it was released the manta then proceeded to stick around and do barrel roles for lots of photo ops - which we are convinced was in appreciation of our efforts."
Sadly marine life isn’t always safe from man’s interference.
Although the area is a protected national park there is an ongoing battle with illegal fishing vessels looking to capitalise on the abundant marine life with the 12 mile exclusion area of the island.
Park rangers have found themselves battling to remove baited fishing lines up to two miles long, which often result in non-commercially valuable species being caught and killed.