The Deadly Deep-Sea Anglerfish
Deep-sea anglerfish are perhaps among the most fascinating and weird ocean creatures known to humans and are likely the first that comes to mind when we think about marine creatures living in the deepest parts of the ocean.
When researchers talk about anglerfish, they are referring to an order of bony fish named for their characteristic mode of predation, during which the fish's modified spine grows its own glowing fleshy mass that acts as a lure for other fish.
There are numerous species of anglerfish, and among them are the deep-sea species that thrive several miles below the surface. Such deep sea-dwelling species include the humpback anglerfish (Melanocetus johnsonii), the triplewart seadevil (Cryptopsaras couesii), and Diceratias trilobus. About 160 different species have been identified by scientists so far.
Deep-sea anglerfish use their bioluminescent "lure" to bait and capture prey under the cover of darkness. They hardly ever survive a journey toward the surface, making them difficult animals to research. What has been learned about deep-sea anglerfish has largely come from scientists studying dead specimens that have been caught in fishing trawls.
The closest researchers came to observing a live deep-sea anglerfish in its natural habitat was during a 2018 expedition around Portugal's Azores islands. The remarkable video showed a female fanfin angler with bioluminescent lights and whisker-like body features projecting from her exterior.
Even more remarkably, the video captured the peculiar mating process of the deep-sea anglerfish. The female anglerfish captured on the video showed how its mate, a tiny male anglerfish, attached to the side of its body. As it turns out, male anglerfish act like "parasites" during reproduction as they latch onto the female's skin and fuse with her. The couple will share even a circulatory system between them.
Researchers have speculated that this parasitic mating method among deep-sea anglerfish benefits both parties, as the male easily receives nutrients from the female while the female receives a constant supply of sperm to fertilize her eggs.
"An anglerfish couple requires about half of the amount of food they would if the male was the same size as the female. [The male] is stripped down to the absolute bare essentials," according to ichthyologist James Maclaine of London's Natural History. "The idea is basically that it's a deep-sea economy measure."
Due to this bizarre method of reproduction, perhaps the anglerfish can be considered the strangest sea animal on this list.
Now that you've checked out some scary ocean animals, learn about these 19 otherworldly fish and insects that featured in "Animal Crossing". Then, see some more of the scariest sea creatures courtesy of photographer Roman Fedortsov.
