Denizens Of The Abyss: The Weird World Of Deep Sea Fishes

Even the deepest parts of the ocean, where water pressures are crushingly high and no sunlight can penetrate, have been colonized by living creatures which are counterparts of the more familiar ones that live in shallower waters and closer to shore. Many have developed unusual adaptations to help them survive in this harsh environment, and one of these is bioluminescent organs that help them to locate or lure prey, as well as to see each other for mating or schooling purposes. Here is one example (a squid)

There are various deep sea fishes that have developed this feature also, as well as unusual feeding habits that help them to make the most of the sparse prey items they come across. Some have enormous mouths with long, sharp teeth that act as traps, and hugely distensible stomachs that allow them to swallow prey that is actually larger than themselves. Here are a few examples:

 Flashlight fish (Photostomias)

Viperfish (Chauliodus)

Gulper eel (Eurypharynx)

Ceratioid Anglerfish (Melanocetus)

Ceratioid Anglerfish (Linophryne)

Some of these fish look more like nightmares than living creatures, but thankfully perhaps, they are mostly rather small in size. The gulper eel looks almost like a windsock with a huge mouth that can engulf any prey item it happens to come across. In the ceratioid anglerfishes (which are cousins of the more familiar shallow water anglerfishes or frogfishes, such as the sargassumfish, see below) the foremost ray of the dorsal fin has developed into a luminescent lure to attract small prey items, and in some such as Linophryne there are weird luminescent barbels growing from the chin. The ceratioid anglerfishes are arguably the most bizarre of all vertebrate creatures. Generally only the female grows to a larger size, whereas the males are tiny and underdeveloped by comparison, and lack lures. In some types, the small males bite down on the female's body and then attach themselves to it, and eventually become completely fused with them so that they simply serve as male organs for reproduction (there can be more than one small male attached to one large female). Apparently this strategy helps to simplify the difficult task for the males and females of these slow moving creatures to get together.

Sargassumfish (Histrio histrio), a shallow-water anglerfish with superb camouflage for blending in with seaweed
crotus crotus
51-55, M
Dec 15, 2012