Here’s how to use DNA to find elusive sharks

Genetic traces in seawater reveal an unseen ‘dark diversity’ that divers and cameras miss

shark

SHARK SIGNS  A baited camera lures a tiger shark and gray reef shark into view, as part of a test to compare what works better to census the elusive fishes: cameras, divers or collecting DNA from seawater. 

Laurent Vigliola/IRD

Pulling DNA out of bottles of seawater collected from reefs has revealed some of what biologists are calling the “dark diversity” of sharks.