Swimmer Adam Walker was simply trying to help the dolphins. The mammals returned the favor in a fashion he may never be able to be repay.

Walker found himself swimming New Zealand's Cook Strait as a part of the Oceans Seven mission. The British open-water swimmer hopes to be the second person ever to complete this group of seven long-distance swims in sites around the world. He is also looking to raise funds for Stop Whaling, a nonprofit group focused on whale and dolphin conservation.

His swim in New Zealand spanned 16 miles, and he didn't expect to encounter any sharks. But, alas, Walker looked down in the middle of the swim and saw a great white below him.

Walker was worried, to say the least. And then a pod of dolphins swam up and surrounded him. The group of about 10 stayed with him for an hour until the shark left.

"I'd like to think they were protecting me and guiding me home!" he posted on Facebook. "This swim will stay with me forever."

A video of his swim with the dolphins was uploaded on Wednesday to YouTube. Many viewers are commenting on dolphins' history with protecting humans, while some are simply in awe of the scene. Even Walker commented that he felt "blown away" by the whole ordeal. The two-minute clip has more than 300,000 hits.

Walker eventually completed the task in 8 hours and 36 minutes. It is his sixth of seven long-distance swims before the mission is finished. It Walker's last swim will take place in August in the Irish Sea.