A family spending the day snorkeling in Hawaii managed to free a 20-foot whale shark ensnared in heavy fishing line.

Joby Rohrer and Kapua Kawelo, their children, and a family friend spotted the whale shark off Kaunolu, Lanai, on July 29.

"We swam with the whale shark for about one hour before deciding that it may be possible to help," Kawelo tells MNN. "My husband is a free diver and could dive down to the depths where the whale shark was swimming, between 30 and 60 feet."

The family thought for a long time before deciding to take action. Ultimately, they felt it was a question of responsibility.

"Being of Hawaiian ancestry, we feel that it was meant to be for us to be at this spot on this day. The Hawaiian word kuleana sums it up," Kawelo says.

Kuleana refers to "a reciprocal relationship between the person who is responsible, and the thing which they are responsible for."

Rohrer and Kawelo and their friend, Jonathan Sprague, are all biologists; they knew the whale was in serious distress and they knew they were equipped to help.

"Being trained as biologists I think we were able to get in tune with how the whale shark was behaving and certainly recognized the importance of trying to assist," Kawelo says. "Had we not, this shark may not have survived to maturity."

Putting the whale shark at ease

That didn't mean the rescue was easy.

"There was a lot of apprehension about wanting to limit the amount of stress for the animal and of course concern for Joby's safety," Kawelo says. "I suggested Joby help and try to cut the rope off, he took things stepwise. First, diving down very close to the animal to see how it reacted. Second, trying to take hold of the rope to see how the whale shark would respond. Then, finally feeling that it was safe to cut, he began cutting."

Once Rohrer felt it was safe to try cutting the rope, it took him five dives, holding his breath each time and sawing at the line with a small 4-inch dive knife. It took a total of about 30 to 40 minutes.

"[It was] certainly intimidating to be so close to such a gigantic animal!" Kawelo says. "Joby has a very calm demeanor especially when he is free diving, [which] helps him to hold his breath a very long time. Needless to say, his adrenaline was pumping. I think Joby's calm nature put the whale shark at ease. At one point it even stopped beating its tail and waited for Joby to remove the final rope.

A life-threatening entanglement

Joby Rohrer swims toward the entangled whale shark. Joby Rohrer swims toward the entangled whale shark. (Photo: Kapua Kawelo)

Although the family didn't know it at the time, the juvenile whale shark was likely the same one that had been spotted several times over the past two weeks with heavy gauge fishing line wrapped around its body. Experts said they thought the entanglement could be life threatening for the animal. They urged anyone who saw the whale shark to call the National Oceanic and Atmospheric Administration (NOAA) so a team could try to help it.

Whale sharks are listed as endangered according to the International Union for Conservation of Nature (IUCN) and it's estimated that the global whale shark population has declined more than 50 percent over the last 75 years. The animals are at risk due to threats like entanglement.

Untrained people shouldn't try disentangling whales or any other marine animals, said Hawaii Department of Land and Natural Resources in a Facebook post describing the rescue.

According to the Hawaii DLNR, the rope was estimated to weigh between 150 to 200 pounds.

"The whale shark swam calmly through the disentanglement process as the divers removed the heavy rope," the post says. "After the whale shark was freed, it stopped swimming back and forth, went into deeper water and swam off."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

Vacationing biologists free tangled whale shark
A Hawaiian family of biologists felt it was their responsibility to save an entangled whale shark.