These divers are on a very important mission; to preserve the world's largest coral reef ecosystem from a predator whose appetite knows no bounds.
One of the team members securing the containment lines around the reef is Mat Trueman, a dive supervisor who now dedicates his life to the fight against Crown of Thorns Starfish (CoTS).
"I like to do my part to make sure we're getting rid of the Crown of Thorns on the reef so that it helps preserve it for future generations," said Mat.
Mat works for the Association of Marine Park Tourism Operators (AMPTO), the organization that manages the Crown of Thorns Control Program in Queensland. He leads teams of up to 12 men and women on 10-day voyages off the coast of Cairns and Port Douglas in Tropical North Queensland.
While it sounds like an idyllic job, diving the Great Barrier Reef four times a day to contain outbreaks is grueling work.
Thanks to a new culling technique, which sees the starfish injected with bile salts from cattle, Mat and his team are reclaiming reef territory faster than ever before. One quick and simple injection euthanizes a starfish, without harming the reef, a far cry from the previous method in which divers had to inject the reef pests up to 30 times.
"Using the old technology and sodium bisulfate it used to take around about six minutes to deal with a (single) Crown of Thorns Starfish," explained Executive Director of AMPTO, Col McKenzie. "These days with a single shot injection, we are able to deal with one every four or five seconds.
"We would be pretty happy if we could take 500 Crown of Thorns in a day using the old method. (With) the new method, the best we've done is 7000."
Also helping AMPTO teams to seek and destroy the starfish is a military invention called the SeaDoo, currently being trialed to help divers move quicker through the water and cover greater territory.
Since 2012, teams from AMPTO have destroyed more than 400,000 of the starfish, which are native to the waters of North Queensland. In healthy numbers Crown of Thorns Starfish are essential to the future of the reef, consuming fast growing corals so that slower growing corals have a chance to develop. If left unchecked, CoTS has the potential to devour large coral outcrops.
Learning about the size and the fragility of the reef along with its beauty is all part of the experience for visitors like Cynthia Diamond from Minneapolis, Minnesota, who last week booked a Reef Magic day trip to Moore Reef just off Cairns.
"I don't think people realize how big (the Reef) is in that it's multiple reefs in one. I was amazed to find out how many square meters (it is) and that it's as big as the country of Japan," said Cynthia.
"People would be amazed if they came here for the first time and discovered what I discovered in an hour under the water."
Eric Fisher, a marine biologist with Reef Magic, said a visit to the reef is as much a lesson in ecology as it is in beauty.
"The education is very important and the reef has millions of stories to tell. We like people to take home a couple of those stories they affiliate with. That helps their understanding of the reef and their care for the reef as well.
"(The Great Barrier Reef) is a world heritage site. It's not just for Australians, it belongs to the whole world," added Eric.
Every cloud has a silver lining, and while the Crown of Thorns may be a threat to the reef, they're providing valuable training and employment for young men and women in the local area.
"We're actually running two programs here," said Col McKenzie. "One is the Crown of Thorns control program and the other is called Skilling Queenslanders for Work program. That second program takes unemployed youth and we teach them to be occupational divers using the Crown of Thorns as the catalyst. So we're getting an employment benefit as well as an ecological benefit."
Dive supervisor Mat is a star graduate of the program. "I was in the original unemployed youth program. After I completed my training I came back a couple of years later and now I'm dive supervisor on the vessel."
It takes the young divers six months to gain their dive master status; so far 145 men and women have graduated from the program with an 85% employment rate.
For more information, please contact Shelley Winkel, Global Publicity Manager Tourism and Events Queensland, at firstname.lastname@example.org.