Anglerfish

The deep sea anglerfish is one of the most bizarre-looking fish in the sea. Known scientifically as Melanocetus johnsoni, it is also one of the best-known creatures of the deep. There are more than 200 species of anglerfish, most of which live in the murky depths of the Atlantic and Antarctic oceans, up to a mile below the surface, although some live in shallow, tropical environments. Generally dark gray to dark brown in color, they have huge heads and enormous crescent-shaped mouths filled with sharp, translucent teeth. Some angler fish can be quite large, reaching 3.3 feet (1 meter) in length. Most however are significantly smaller, often less than a foot. It can weigh up to 110 lbs (50 kg).

Their most distinctive feature, worn only by females, is a piece of dorsal spine that protrudes above their mouths like a fishing pole—hence their name. Tipped with a lure of luminous flesh this built-in rod baits prey close enough to be snatched. Their mouths are so big and their bodies so pliable, they can actually swallow prey up to twice their own size.

The male, which is significantly smaller than the female, has no need for such an adaptation. In lieu of continually seeking the vast abyss for a female, it has evolved into a permanent parasitic mate. When a young, free-swimming male angler encounters a female, he latches onto her with his sharp teeth. Over time, the male physically fuses with the female, connecting to her skin and bloodstream and losing his eyes and all his internal organs except the testes. A female will carry six or more males on her body.

The deep sea anglerfish has a round body that resembles a basketball, and indeed, it looks like it could easily swallow one. It has a very large mouth with sharp, fang-like teeth. Its grotesque appearance has earned it the nickname "common black devil". Due to its wide, round body, it cannot swim very fast. Its skin is specially adapted to reflect blue light. The anglerfish's lighted lure glows with the help of millions of bioluminescent bacteria. Since nearly all light emitted from bioluminescent creatures is blue, the anglerfish can be nearly invisible to other deep sea animals.

The anglerfish uses its illuminated lure as its hunts for prey. This specialized spine is highly manoeuvrable and can be moved in any direction. The anglerfish is known to remain completely motionless, waving its lure back and forth like a fishing pole. When the prey fish gets close enough, the angler snaps it up with its powerful jaws and swallows it whole. The sharp teeth of the angler are angled inwards, which helps to prevent the prey from escaping. The anglerfish can extend both its jaw and its stomach to an incredible size, allowing it to swallow prey twice the size of its entire body. Since food can be scarce in the deep sea, this special adaptation allows it to stock up on food during times of plenty.

The deep sea angler is found throughout the world's oceans at depths of over 3,000 feet (914 meters). At this depth, there is almost no light and the water is near freezing. Many species of anglerfish are fished commercially throughout the world. They are compared to lobster in taste and texture. In Japan, anglerfish is considered a delicacy and can fetch a premium price.