Photophores (light producing organs) are used in several ways by various fishes. The deepwater lanternfish, in the family Myctophidae, has photophores and lives in deep in the water where there is not very much ambient (natural) light (SF Fig. 4.10).

Special Feature Questions

1. Many bacteria and small invertebrates are luminescent. How might a lanternfishes’ photophores help it attract prey?
2. They light from photophores helps to break up the outline of the fish against backscattered light coming down from above. Explain how this might provide a type of countershading camouflage for the lanternfish.
3. Most lanternfish have species-specific patterns of photophores, and patterns can also vary between males and females. Explain how photophores might help with communication.