Gulper Eel

Name: Gulper eel
Scientific Name: Eurypharynx pelecanoides
FAQ

• Saccopharyngiformes is an order of unusual ray-finned fish superficially similar to eels, but with many internal differences. Most of the fish in this order are deep-sea types known from only a handful of specimens such as the Umbrella Mouth Gulper Eel. 
• Saccopharyngiformes are also bioluminescent in several species. Some, such as the swallowers, can live as deep as 10,000 feet (3,000 m) in the ocean, well into the aphotic zone.
• Saccopharyngiforms lack several bones, such as the symplectic bone, the bones of the opercle, and ribs. They also have no scales, pelvic fins, or swim bladder. 
• The jaws are quite large, and several types are notable for being able to consume fish larger than themselves. Their myomeres (muscle segments) are V-shaped instead of W-shaped like in all other fish, and their lateral line has no pores, instead it is modified to groups of elevated tubules.
• DIET: The gulper eel eats fish, copepods, shrimp, and plankton. It uses its mouth like a net by opening its large mouth and swimming at its prey. Due to the gulper eel's specialised body shape, it is a poor swimmer and relies on the luminescent organ at the tip of its tail to attract prey.

Flashfish

Name: Flashfish
Scientific Name: Kryptophanaron alfredi
FAQ:

• The flashlight fish are a family, the Anomalopidae, of beryciform fish. There are some unrelated fish with similar features, some of which are also called flashlight fish. 
• Notable among these are the deep sea lanternfish, of the family Myctophidae, of which there are over 200 species.
• Flashlight fishes live in tropical waters across the world. Some species move to shallow waters or coral during the night, but otherwise, they are exclusively deep water fish. 
• SIZE: They are typically about 14 centimeters (5.5 in) in adult length, although some species reach twice this size. 
• DIET: They feed on small crustaceans.
• Flashlight fish are named for their large bioluminescent organs. These are located beneath the eyes and contain luminous red bacteria. 
• Different species have an array of methods for shielding the light to escape from predators. The light is used to attract prey, and for communication.

Antarctic Krill

Name: Antarctic krill
Scientific Name: Euphausia superba
FAQ:

• Antarctic krill, Euphausia superba, is a species of krill found in the Antarctic waters of the Southern Ocean. Antarctic krill are shrimp-like invertebrates or crustaceans that live in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic meter. 
• DIET: They feed directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic (open ocean) life cycle.
• GROWTH: They grow to a length of 6 centimeters , weigh up to 2 grams, and can live for up to six years. They are a key species in the Antarctic ecosystem and are, in terms of biomass, probably the most abundant animal species on the planet
• Krill are often referred to as light-shrimp because they can emit light, produced by bioluminescent organs. These organs are located on various parts of the individual krill's body: one pair of organs at the eye-stalk, another pair on the hips of the second and seventh thoracopods, and singular organs on the four pleonsternites. These light organs emit a yellow-green light periodically, for up to 2–3 s. 
• They are considered so highly developed that they can be compared with a torchlight: a concave reflector in the back of the organ and a lens in the front guide the light produced, and the whole organ can be rotated by muscles. 
• The function of these lights is not yet fully understood; some hypotheses have suggested they serve to compensate the krill's shadow so that they are not visible to predators from below; other speculations maintain that they play a significant role in mating or schooling at night.
• The krill's bio-luminescent organs contain several fluorescent substances. The major component has a maximum fluorescence at an excitation of 355 nm and emission of 510 nm.

Cookie Cutter Shark

 
Name: cookiecutter shark
Scientific Name: Isistius brasiliensis
FAQ:

• The cookiecutter shark , also called the cigar shark, is a species of small dogfish shark in the family Dalatiidae. 
• This shark occurs in warm, oceanic waters worldwide, particularly near islands, and has been recorded from as deep as 3.7 km (2.3 mi). It migrates vertically up to 3 km (1.9 mi) every day, approaching the surface at dusk and descending with the dawn. 
• GROWTH:Reaching only 42–56 cm (17–22 in) in length, the cookiecutter shark has a long, cylindrical body with a short, blunt snout, large eyes, two tiny spineless dorsal fins, and a large caudal fin. 
• It is dark brown in color, with light-emitting photophores covering its underside except for a dark "collar" around its throat and gill slits.
• The name "cookiecutter shark" refers to its feeding habit of gouging round plugs, like a cookie cutter, out of larger animals. Marks made by cookiecutter sharks have been found on a wide variety of marine mammals and fishes, as well as on submarines, undersea cables, and even human bodies. It also consumes whole smaller prey such as squid. 
• Cookiecutter sharks have adaptations for hovering in the water column and likely rely on stealth and subterfuge to capture more active prey. Its dark collar seems to mimic the silhouette of a small fish, while the rest of its body blends into the downwelling light via its ventral photophores. When a would-be predator approaches the lure, the shark attaches itself using its suctorial lips and specialized pharynx and neatly excises a chunk of flesh using its bandsaw-like set of lower teeth. 
• This species has been known to travel in schools.
• The intrinsic green luminescence of the cookiecutter shark is the strongest known of any shark, and has been reported to persist for three hours after it has been taken out of water .The ventrally positioned photophores serve to disrupt its silhouette from below by matching the downwelling light, a strategy known as "counter-illumination", that is common among bioluminescent organisms of the mesopelagic zone. The individual photophores are set around the denticles and are small enough that they cannot be discerned by the naked eye, suggesting that they have evolved to fool animals with high visual acuity and/or at close distances.
• Set apart from the glowing underside, the darker, non-luminescent collar tapers at both sides of the throat and has been hypothesized to serve as a lure by mimicking the silhouette of a small fish from below. The appeal of the lure would be multiplied in a school of sharks. 
• If the collar does function in this way, the cookiecutter shark would be the only known case of bioluminescence in which the absence of light attracts prey, while its photophores serve to prevent premature detection by incoming would-be predators. As the shark can only match a limited range of light intensities, its vertical movements likely serve to preserve the effectiveness of its disguise across various times of day and weather conditions.
• DIET: Virtually every type of medium to large-sized oceanic animal sharing the habitat of the cookiecutter shark is open to attack: bite scars have been found on cetaceans, dugongs, sharks, deepwater stingrays, and bony fishes.  The cookiecutter shark also regularly hunts and eats entirely squid