Myctophiformes

Myctophiformes is an order of marine ray-finned fishes that includes the lanternfishes and their relatives. The two living families are Myctophidae (lanternfishes) and Neoscopelidae. Myctophiformes are among the most abundant and widespread fishes of the open ocean, especially in the mesopelagic zone, and they play a central role in midwater ecosystems worldwide.

Most species are small to medium-sized, with slender, streamlined bodies and relatively large eyes adapted to low light. A defining feature is the presence of photophores—bioluminescent organs—arranged in species-specific patterns on the head, body, and fins. Light production is used for camouflage through counter-illumination, as well as for signaling and mate attraction.

Ecology and behavior: Myctophiformes inhabit midwater zones from tropical to polar regions and often form dense, schooling populations. They undertake diel vertical migrations, rising toward the surface at night to feed on zooplankton and returning to deeper waters by day. Their diet includes copepods, krill, and other planktonic crustaceans. They are an important prey source for larger pelagic fishes, squid, seabirds, and marine mammals. The light-emitting organs also likely facilitate species recognition and reproduction.

Life history and significance: Reproduction is typically pelagic, with eggs and larvae developing in the open ocean. Growth rates are generally rapid, and many species have short lifespans. Myctophiformes contribute enormously to oceanic energy transfer and carbon cycling through their vertical migrations, and the deep scattering layer often observed by sonar is largely composed of lanternfishes and related taxa.