Surprising fish fact

by Arthur Fisher

More than 90 percent of the fish and other marine creatures that live in the oceans mid-watersfrom 300 to 3,000 feet deep-glow in the dark.The light emitted by living things is called bioluminescence. Why do some fish, squid, jellyfish, and other deep-sea dwellers glow? Well, some use a lighted lure to attract prey, the way a fisherman sometimes baits a hook with a brightly painted fake fish. Others use their light to attract (or to find) a mate in the dark.

But most glowing sea creatures use light as a kind of camouflage. The glow makes it harder for other creatures who might be looking for a tasty treat to see them. Hows that? A fish glows in the dark to hide? Heres the scoop: Seen from below, a fish would be silhouetted against the faint light cast downward from the oceans sunlit surfacea tempting tip-off to a hungry predator. But a fish that glows can avoid becoming the "catch of the day" by precisely balancing the downcoming light with its own bioluminescence. Biologists call this smart fish trick counter-illumination.

Ocean Planet Exhibition Floorplan

gene carl feldman ( (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)