Deep Sea Anglerfish

An anglerfish is a unique fish with a bizarre look, which belongs to the order Lophiiformes. Some families of this order live in the deep sea, while a few are shallow water species. The scientific name of the deep sea anglerfish is Melanocetus johnsoni. The fish got its name from its unique mode of predation. It possesses a fleshy growth that sprouts from the middle of the head, which it uses as a fishing lure, and resembles a fishing pole to attract the prey. This is considered similar to the act of angling, and so the name 'anglerfish'. About 200 species of anglerfish can be found in the oceans across the world.

Anglerfish Residing in Deep Sea

Physical Appearance
It has a ferocious look, though it's not too big in size. This ugly fish has earned the name of 'common black devil' due to its unsightly appearance. What gives the fish its terrible look is its large mouth with the sharp, fang like teeth. The teeth of anglerfish can look even more intimidating than the teeth of the sharks. This ugly fish has a round body that looks like a basketball. It can reach only a length of about 12 cm.

The body of anglerfish can be dark gray, brown or black in color, and the skin can reflect the blue light. This in turn, helps it to remain invisible to other deep sea fish and animals, as almost all bioluminescent fish or creatures of the deep sea emit blue light. Its eyes are too small. The fish possesses one, or more of such long filaments, that sprung from the center of its head. These are the modified spines of the anterior dorsal fin, but they look like filaments. Usually, the longest filament is the first spine or illicium, that protrudes above the eyes, and then terminates in an irregular mass of flesh at the tip of the spine, which is called 'esca'. This serves as a lure for the anglerfish, which can be moved back and forth. The spine attached to the lure is also movable.

Predation
As has been mentioned already, the anglerfish has an extraordinary mode of predation. It basically uses its lure, which emits light to attract its prey. While remaining motionless, it waves its lure back and forth, and waits for the prey to come closer to its mouth. The specialized spine attached to the lure can also be moved by the fish in any direction. Moreover, the 'esca' is connected with the mouth reflex, so that when the prey touches it, the anglerfish can instantly snap the prey with the powerful jaw and then swallow it. The teeth of the fish are bent inwards, for which the prey cannot escape once its enters the mouth of the anglerfish. Anglerfish can swallow a prey twice the size of its body, as it can distend its jaw and stomach. This is because, the bones of this fish are thin and flexible, due to which the fish can extend its jaw and the stomach to an incredible size. So, it catches its prey with the help of light emitted from the esca. This bioluminescence is the result of the large number of bacteria that enter the esca, and produce a bluish or greenish light.

Reproduction
The mating of male and female anglerfish is quite unusual. The male anglerfish is much smaller than the female, and looks quite different. The male is usually not larger the size of a small finger. The male fish is black in color, and it possesses well-developed olfactory organs at birth, with the help of which it can detect scent in water. Due to its small size, the male anglerfish cannot effectively find foods, and moreover, its digestive system also starts to degenerate once its matures.

All these makes the male anglerfish desperate to find a female and then mate. It can detect the pheromones of the female anglerfish with the help of its olfactory organs. When the male anglerfish finds the female, it attaches itself to the body of the female with its small hook like teeth. The male anglerfish then bites into the skin of the female. It releases an enzyme that dissolves the skin of its mouth and that of the body of the female, after which the two fuse together to the level of the blood vessels. Then the male slowly loses all its body parts, except for the pair of gonads. These gonads release sperms, when the female is ready to release the eggs. The male in this way remains as a parasite in the body of the female, and draws nourishment from there.

In this way, the female anglerfish can carry up to six males on her body. This bizarre method of reproduction makes sure that when the female is ready to spawn, she does not have to look for the male, as he is already available. After fertilization, the female lay the eggs in a thin sheet of transparent gelatinous material, which can be 2 to 3 feet wide and about 25 to 30 feet long. This sheet with the eggs floats in the sea, till the eggs hatch into larvae. The larvae usually feed on the surface of the sea, until they mature.

It is really a unique fish, not only from the way it looks and hunts its prey, but also the way it reproduces. The exceptional method of reproduction in the anglerfish was discovered when scientists noticed that all the anglerfish that they captured were females. Besides this, all the female fish were found to have parasites attached to them. Later, the scientists were able to figure out that what seemed to be parasites to them were actually the remains of the male anglerfish. Subsequently, they unveiled this unique reproduction method of anglerfish including the deep sea anglerfish. It can be found at the depth of over 3,000 feet in the oceans. Despite their frightening look, anglerfish are consumed in many parts of the world, especially in Japan.