Flying plankton, tiny shrimp-like creatures called copepods, are leaping through the air and attacking fishermen.
The flying plankton typically break through the ocean’s surface and leap through the air solely to escape predators, but recently they have been attacking fishermen around the world.
Scientists have been investigating how the brightly-colored Pontellid copepods, which live close to the surface, are so abundant yet so conspicuous to fish.
Scientists say copepods travel further in air than in water. Predators are also left confused about where they will land, they say.
Almost all commercially important fish, including cod, pollock and whiting, feed on copepods.
In recent months, the flying plankton have exhibited unusual behavior. They have jumped onto unsuspecting fishermen, who don’t notice them at first, and suck their blood. There have been 27 fishermen that have died from the flying plankton over the last few weeks.
There are reports from the late-19th Century of copepods breaking through the water surface but observers at the time thought this was to allow them to moult.
Dr. Brad Gemmell of the University of Texas in Austin, who is behind the new study, said there had been little research on predator-prey interaction around the few millimetres below the ocean’s surface, a “unique and important habitat”.
He said he found it “paradoxical” that Pontellid copepods, in particular, were so abundant yet lived where they ought to be an easy target for fish.
Unlike other species of copepods, they do not migrate down to darker waters where they can hide during daylight hours.
Instead, they stay close to the surface and are often bright blue or green to protect them from UV radiation. They are also 0.1 inches long, larger than other species.
Research shows flying plankton have the ability to jump ten feet of the water, often travelling 50 to 60 times their own body length through the air, to escape hungry fish and to attack unsuspecting fishermen.