Anglerfish Sea Animal
Scientific name: Lophiiformes
Order: Lophiiformes; Garman, 1899
Mass: Angler: 32 kg,
Lophius americanus: 12 kg
The anglerfish is a fish of the teleost order Lophiiformes. It is a bony fish named for its characteristic mode of predation, in which a fleshy growth from the fish’s head acts as a lure for other fish.
The anglerfish is a fish of the teleost order Lophiiformes (/ˌlɒfiɪˈfɔːrmiːz/).It is a bony fish named for its characteristic mode of predation, in which a fleshy growth from the fish’s head (the esca or illicium) acts as a lure for other fish.Some anglerfish are notable for extreme sexual dimorphism and sexual symbiosis of the small male with the much larger female, seen in the suborder Ceratioidei. In these species, males may be several orders of magnitude smaller than females.Anglerfish occur worldwide. Some are pelagic (dwelling away from the sea floor), while others are benthic (dwelling close to the sea floor).Some live in the deep sea (e.g., Ceratiidae), while others on the continental shelf (e.g., the frogfishes Antennariidae and the monkfish/goosefish Lophiidae).
Pelagic forms are most laterally compressed, whereas the benthic forms are often extremely dorsoventrally compressed (depressed), often with large upward-pointing mouths.Biology of AnglerfishAnatomyAll anglerfish are carnivorous and are thus adapted for the capture of prey. Ranging in color from dark gray to dark brown, deep-sea species have large heads that bear enormous, crescent-shaped mouths full of long, fang-like teeth angled inward for efficient prey grabbing.
Their length can
vary from 2–18 cm (1–7 in), with a few types getting as large as 100 cm (39 in). , but this variation is largely due to sexual dimorphism with females being much larger than males.Frogfish and other shallow-water anglerfish species are ambush predators, and often appear camouflaged as rocks, sponges or seaweed.Most adult female ceratioid anglerfish have a luminescent organ called the esca at the tip of a modified dorsal ray (the illicium or fishing rod). The organ has been hypothesized to serve the obvious purpose of luring prey in dark, deep-sea environments, but also serves to call males’ attention to the females to facilitate mating.
The source of luminescence
is symbiotic bacteria that dwell in and around the esca, enclosed in a cup-shaped reflector containing crystals, probably consisting of guanine.In some species, the bacteria recruited to the esca are incapable of luminescence independent of the anglerfish, suggesting they have developed a symbiotic relationship and the bacteria are unable to synthesize all of the chemicals necessary for luminescence on their own.Swimming and energy conservationIn 2005, near Monterey, California, at 1474 metres depth, an ROV filmed a female ceratioid anglerfish of the genus Oneirodes for 24 minutes. When approached, the fish retreated rapidly, but in 74% of the video footage, it drifted passively, oriented at any angle.
When advancing, it swam intermittently at a speed of 0.24 body lengths per second, beating its pectoral fins in-phase.
The lethargic behaviour
of this ambush predator is suited to the energy-poor environment of the deep sea.Another in situ observation of three different whipnose anglerfish showed unusual inverted swimming behavior. Fish were observed floating inverted completely motionless with the illicium hanging down stiffly in a slight arch in front of the fish.The illicium was hanging over small visible burrows. It was suggested this is an effort to entice prey and an example of low-energy opportunistic foraging and predation. When the ROV approached the fish, they exhibited burst swimming, still inverted.The jaw and stomach of the anglerfish can extend to allow it to consume prey up to twice its size. Because of the small amount of food available in the anglerfish’s environment this adaptation allows the anglerfish to store food when there is an abundance.