being below the tail. Lanternfish are generally small fish, ranging from about in length, with most being under . Shallow-living species are an iridescent blue to green or silver, while deeper-living species are dark brown to black. Ecology Lanternfish are well known for their diel vertical migrations: during daylight hours, most species remain within the gloomy bathypelagic zone, between deep, but towards sundown, the fish begin to rise into the epipelagic zone, between deep. The lanternfish are thought to do this to avoid predation, and because they are following the diel vertical migrations of zooplankton, upon which they feed. After a night spent feeding in the surface layers of the water column, the lanternfish begin to descend back into the lightless depths and are gone by daybreak. By releasing fecal pellets at depth, Laternfish make the carbon capture process called biological pump more efficient. Most species remain near the coast, schooling over the continental slope. Different species are known to segregate themselves by depth, forming dense, discrete conspecific layers, probably to avoid competition between different species. Due to their gas bladders, these layers are visible on sonar scans and give the impression of a "false bottom"; this is the so-called deep scattering layer that so perplexed early oceanographers (see below). Great variability in migration patterns occurs within the family. Some deeper-living species may not migrate at all, while others may do so only sporadically. Migration patterns may also depend on life stage, sex, latitude, and season. The arrangements of lanternfish photophores are different for each species, so their bioluminescence is thought to play a role in communication, specifically in shoaling and courtship behaviour. The concentration of the photophores on the flanks of the fish also indicate the light's use as camouflage; in a strategy termed counterillumination, the lanternfish regulate the brightness of the bluish light emitted by their photophores to match the ambient light level above, effectively masking the lanternfishes' silhouette when viewed from below. A major source of food for many marine animals, lanternfish are an important link in the food chain of many local ecosystems, being heavily preyed upon by whales and dolphins, large pelagic fish such as salmon, tuna and sharks, grenadiers and other deep-sea fish (including other lanternfish), pinnipeds, sea birds, notably penguins, and large squid such as the jumbo squid, Dosidicus gigas. Lanternfish themselves have been found to feed on bits of plastic debris accumulating