How eDNA technology is changing the game for protecting ocean species

New, noninvasive techniques turn samples of sea water into a treasure trove of genetic information about the species below

Hanging over the side of the boat, Nahi El Bar Jiyed scoops up a jug of sea water, then carefully pours it into a large syringe. While the sample may seem ordinary, to the biologist it's a trove of secrets: the DNA of every living creature swimming below.

He presses the water sample through a filter about the size of his hand, which captures the DNA fragments, then repeats the process several more times. Meters away, a sea turtle emerges for a breath then retreats to the seagrass meadow below.

Scientists and students take water samples at Banc d'Arguin national park in Mauritania