Lanternfish, scientifically known as myctophids, represent one of the most numerous vertebrate families on Earth. These small deep-sea fish are found in oceans across the globe, inhabiting depths from near the surface to over a mile deep. They are characterized by their ability to produce light through specialized organs called photophores, which are arranged in unique patterns on their bodies.
Primary Food Sources
Lanternfish primarily consume zooplankton, tiny drifting animals found throughout the ocean. Their diet commonly includes copepods, small crustaceans abundant in marine waters. Euphausiids, also known as krill, form a significant component of their diet, particularly for larger lanternfish species.
Other small crustaceans such as ostracods and amphipods are also regular food items for many lanternfish. While zooplankton constitutes the bulk of their intake, some larger lanternfish species may also prey on small fish larvae or other small fish.
Lanternfish are considered opportunistic feeders, consuming what is available in their environment. This adaptability allows them to thrive in diverse oceanic regions, from tropical to polar waters. Their feeding habits link the microscopic world of plankton to larger marine life.
Feeding Strategies and Habitat Influence
Lanternfish employ specific behaviors to acquire their food, influenced by their deep-sea habitat. A prominent strategy is diel vertical migration (DVM), where they ascend from deeper, darker waters to shallower, food-rich zones at night. During daylight hours, they descend back to depths between 300 to 1,500 meters to avoid visual predators.
This nightly ascent allows them to feed on abundant surface zooplankton. Their bioluminescence may also play a role in feeding. While primarily used for camouflage, bioluminescence might also help attract or illuminate small prey.
The availability and distribution of prey in both the mesopelagic (twilight) and epipelagic (surface) zones directly influence their feeding patterns. Some lanternfish populations may adjust their migration depth or even forego migration depending on prey density and predator presence. This flexibility ensures they can efficiently forage while minimizing exposure to threats.
Ecological Significance of Their Diet
The feeding habits of lanternfish position them as a central component of marine food webs. By consuming vast quantities of zooplankton during their nocturnal migrations, they transfer energy from lower trophic levels to higher ones. They serve as a primary food source for a wide array of marine animals.
Many commercially important fish, such as tuna and salmon, rely on lanternfish as a significant part of their diet. Marine mammals like dolphins and whales, along with various seabirds and squid, also consume lanternfish.
Lanternfish contribute to the “biological pump,” a process that sequesters carbon from the atmosphere into the deep ocean. As they feed on surface-dwelling organisms and then migrate to deeper waters, they transport organic carbon. This carbon is then released through their metabolism, respiration, or fecal pellets, moving it into long-term storage in the deep sea.