‘Ocean detectives’ boost protection for endangered marine life

Volunteers are swimming in the sea to help science conserve some of the world’s rarest fish. Scuba divers and snorkelers are among those helping to identify endangered species, such as giant guitarfishes, whip-stingrays and thresher sharks.

They are collecting environmental DNA which comprises billions of fragments of marine creatures—scales, blood, saliva, feces, and more—which can help paint a picture of which creatures live close or have passed by.

Around 30 scuba diving and snorkeling volunteers have taken up the challenge, including British Sub-Aqua Club member Rosie Horner, who said, “It is great to contribute to scientific research by doing the thing I love most—scuba diving. These forensic techniques uncover species that we may have missed on our dives.”

“Where the volunteers come in is we attach a plastic ball full of cotton to their wet suit; and as they swim, that little ball becomes completely soaked with water, trapping the eDNA fragments dissolved in it,” explained Professor Stefano Mariani, a marine biologist at Liverpool John Moores University who coordinates the project.

“No-one has to take photographs, notes or even keep a look out. All they need do is swim around in the ocean to contribute to conservation science,” he said.

Dr. Erika Neave, a Ph.D. researcher at Liverpool John Moores University, said, “The volunteers give us their seawater-soaked cotton—or stick it in the post to the lab—and by sequencing what they collect, we can build up a picture of the local fauna.”

The method, she says, is simple, inexpensive and saves complex scientific explorations and audits of marine life.

It is also effective, says Neave. “We were able to perfect the technique based on feedback from a small network of volunteers, who dived in a dozen locations in the Atlantic, Pacific and Indian oceans and detected 275 unique species from varied marine habitats. The swimming motion of divers was more effective than just dipping the cotton into the water.”

“DNA Divers: Volunteer-based eDNA capture for local and global marine biodiversity monitoring” is published in Methods in Ecology and Evolution.