Deep sea fish is the term given to fishes that live below the photic zone of the ocean. The types of Deep Sea Fish are Lanternfish, flashlight fish, cookie cuter shark, bristle mouths, anglerfish and Viperfish, hatchet, gulper eel and whale. The endangered species of deep sea include blue hyke, spiny eel, spiny tail skate, round nose grenadier and onion-eye grenadier. They are on the verge of extinction due to the shift of commercial fisheries from the continental slopes to continental shelves area up to 6000 meters. Another contributing factor is the slow reproduction of these fishes.
The photic zone lies few hundred meters below the water; this region is not much explored. This fishes are weird and most mysterious species on Earth. Although they have evolved in harsh climate, they don't survive in laboratory conditions and so they are still unknown. Less amount of research has been done about them as the expenses of equipments for exploring deep sea is high. They are recognized by their scientific names as only scientists know about them. Many species in the deep sea emit lights called luminescent which attracts other fish.
Apart from these they live under high pressure and the climate is very cold here. The water has high quantity of nutrients which are obtained from the accumulated wastes sinking form the high level. Oxygen content in this water is high which is about 5-6%.
There is very less light reaching this surface of the earth and so the process of photosynthesis does not take place. They survive on the organic matter that sinks on from higher surface. These areas are poor in productivity. So the fishes here have jelly-like flesh and have a minimal bone structure.
In order to survive from the predators, they use the technique of Camouflage in which they merge into the surroundings. Some animals allow the light to pass through them and become transparent. Whereas the fishes that are black colored could easily escape in the darkness. These fishes live in areas where there is no natural light available, so they cannot rely on the eyes for feeding and mating. They have adapted to darkness by large eyes known as bioluminescent or feelers which help them to locate their mates.
Types of Deep sea fishes:
It accounts for 65% of all the deep sea biomass. Their length varies between 3cm to 35 cm and has a pattern of photophores all down the body. It swims to the top to catch the prey. These fishes if are brought above to the surface they cannot survive and their organs and eyes will explode.
Sea Whales : They dive in deep sea in search of prey.
Viperfish: It is one of the scariest fish found in deep sea. It has long sharp clear teeth and light is used to catch their prey.
Hatchet: It possesses light that grabs the attention of their prey.
Gulper eel : They have a huge head and mouth to gulp their prey easily. They have elastic stomachs help them to eat large fishes.