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Tricky Tactics

April 3, 2017

A team of WHOI researchers on the R/V Neil Armstrong encountered these unusual-looking specimens last summer, about 100 miles off the southern coast of New England. They collected the fish at night, between about 300 and 600 meters (980 and 1970 feet) below the surface, using a multi-net system called a MOCNESS. Both viperfish (top) and dragonfish (bottom) live in near darkness, in what’s known as the mesopelagic or “twilight zone.” To attract their prey, the fish use a bioluminescent lure, or esca, suspended like bait on a fishing rod from either a dorsal spine, in the case of the viperfish, or a chin barbel, as with the dragonfish. The animal uses the light to trick zooplankton or small fish into approaching—and becoming the next meal. (Photo by Joel Llopiz, Woods Hole Oceanographic Institution)