Essay On Angler Fish

Angler fish is a bony fish from order of Lophiiformes. There are 18 families, 5 suborders and more than 200 species of anglerfish. Most angler fish around the world live in the bathypelagic zone of the Atlantic and Antarctic oceans. They can survive up from 1000m to 4000m below the surface, although some live in shallow waters too. (National Geographic)

Most of the angler fish are generally dark grey to dark brown in colour, they have huge heads and enormous crescent-shaped mouths filled with sharp and translucent teeth. The size of angler fishes are normally smaller and often less than a foot but there still some of them can be quite long, reaching 1 meter. However, the size of males and females are not the same as females are much bigger than males. Angler fishes have a distinctive feature that a long bioluminescent rod sprouted from the middle of their heads and which is actually an extension of a dorsal spine.

However, all bioluminescence are utilized for similar reasons as it allows marine species to communicate, attract prey and mate at the depths of the ocean.

The way for marine creatures to control the luminescent light is by the density of the bacterial population to form colonies. When a certain density of bacteria is reached, this cause the luminescent light produced. If creatures want to shut down the luminescent light, bacteria will be released out. However, the density of the bacterial populations is influenced by the oxygen and nutrient provided by the host that can result in slower growth rates if oxygen and nutrient levels are not maintained. Low osmolarity increases luminescence and decreases the growth of bioluminescent bacteria due to a lack of oxygen. The opposite is also true, high osmolarity decreases luminescence while increasing growth