Lanternfish (Family Myctophidae)

FishDeep seaBioluminescentMarine

Overview

Lanternfish (family Myctophidae) are small deep-sea fish — typically just a few centimetres long — found in oceans worldwide. Their name comes from rows of light-producing organs, called photophores, that dot the head and body and glow with a soft blue-green light.

What lanternfish lack in size they make up in sheer numbers. They are extraordinarily abundant and form a huge part of the deep-ocean fish biomass; by some estimates they are among the most numerous vertebrates on the planet, and they are a vital link in marine food webs.

Note: Myctophidae contains hundreds of species; details here describe the family broadly.

Habitat & Range

Lanternfish live in the open ocean, mostly in the twilight (mesopelagic) zone roughly a few hundred to a thousand metres down by day. At night many rise toward the surface to feed. They occur in all the world's major oceans, from the tropics to polar seas, and make up much of the life of the deep mid-water.

Diet

Lanternfish feed mainly on tiny drifting animals — zooplankton such as copepods and krill, and other small invertebrates. In turn they are eaten by a vast range of larger animals, including bigger fish, squid, seabirds, seals, dolphins, and whales, which makes them a crucial step in transferring energy up the ocean food chain.

Behavior

Lanternfish are famous for taking part in the largest movement of animals on Earth: the daily vertical migration. Each evening huge numbers swim up from the depths to feed in richer surface waters under cover of darkness, then descend again before dawn to hide from predators in the dim deep — a daily rhythm so dense it shows up on ship sonar as a moving “deep scattering layer.” Their photophores are thought to help with camouflage (matching faint light from above), signalling to others of their kind, and possibly confusing predators.

Human Interaction & Conservation

People rarely see lanternfish, but they are immensely important: as prey for commercially valuable fish and marine mammals, and as part of the “biological pump” that carries carbon from the surface into the deep sea during the nightly migration. There is growing interest in fishing them at scale, which raises concerns about the effects on ocean food webs. Consult marine science and fisheries sources for current information.

More photos of the lanternfish