The mesopelagiczone, also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins at the depth where only 1% of incident light reaches and ends where there is no light; the depths of this zone are between approximately 200 to 1,000 meters below the ocean surface.
The bathypelagic zone or bathyal zone is the part of the open ocean that extends from a depth of 1,000 to 4,000 m below the ocean surface. It lies between the mesopelagic above and the abyssopelagic below. The bathypelagic is also known as the midnight zone because of the lack of sunlight; this feature does not allow for photosynthesis-driven primary production, preventing growth of phytoplankton or aquatic plants. Although larger by volume than the photic zone, human knowledge of the bathypelagic zone remains limited by ability to explore the deep ocean.
Lanternfish are small mesopelagic fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represented by 246 species in 33 genera, and are found in oceans worldwide. Lanternfishes are aptly named after their conspicuous use of bioluminescence. Their sister family, the Neoscopelidae, are much fewer in number but superficially very similar; at least one neoscopelid shares the common name "lanternfish": the large-scaled lantern fish, Neoscopelus macrolepidotus.
Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs.
A viperfish is any species of marine fish in the genus Chauliodus. Viperfishes are mostly found in the mesopelagic zone and are characterized by long, needle-like teeth and hinged lower jaws. A typical viperfish grows to lengths of 30 cm (12 in). Viperfishes undergo diel vertical migration and are found all around the world in tropical and temperate oceans. Viperfishes are capable of bioluminescence and possess photophores along the ventral side of their body, likely used to camouflage them by blending in with the less than 1% of light that reaches to below 200 meters depth.
Argyropelecus hemigymnus, the half-naked hatchetfish, short silver hatchetfish or spurred hatchetfish, is a deep-sea hatchetfish of the genus Argyropelecus found mesopelagically in the Atlantic, Indian, and Pacific Oceans as well as in the Mediterranean Sea. It is a small species rarely exceeding 38 millimetres (1.5 in) standard length. It feeds on zooplankton, particularly ostracods and copepods. Sexual maturation occurs at length of about 22 mm, and adult males have more developed olfactory organs than females, i.e. the species is sexually dimorphic.
Lightfishes are small stomiiform fishes in the family Phosichthyidae
Maurolicus muelleri, commonly referred to as Mueller's pearlside,Mueller's bristle-mouth fish, or the silvery lightfish, is a marine hatchetfish in the genus Maurolicus, found in deep tropical, subtropical and temperate waters of the Pacific Ocean and the Atlantic Ocean, from the surface to depths of 1,500 metres (4,900 ft). It can grow to a maximum total length of 8 centimetres (3.1 in).
Sloane's viperfish, Chauliodus sloani, is a predatory mesopelagic dragonfish found in waters across the world. The species was first described by German scientists Marcus Elieser Bloch and Johann Gottlob Schneider in their 1801 book Systema ichthyologiae: iconibus CX illustratum, volume 1. Female C. sloani reach maturity between 133 and 191 mm, while males likely reach maturity at slightly smaller body lengths. It has two rows of photophores along its ventral side. It is believed that C. sloani can adjust the intensity of bioluminescence of the ventral photophores to camouflage itself from predators that might see its shadow from below.
The abyssal grenadier, Coryphaenoides armatus, is an abyssal fish of the genus Coryphaenoides, found in all the world's oceans, at depths between 800 and 4,000 metres. Its adult length is 20 to 40 centimetres, although Fishbase gives lengths up to 1 metre. The abyssal grenadier's body is unique in that it contains two dorsal spines and about 124 dorsal soft rays, which are the flexible jointed rays supporting a fin nearest to the back in the spinal column. It has no anal spines, but has 115 anal soft rays along its body. The head and eyes of this fish are very large, while the mouth is very small. The color of the abyssal grenadier is brown apart from the abdomen, which is bluish.
Myctophum is a genus of lanternfishes, some species of which, such as M. punctatum are noted for having the Stylophthalmine trait in their larval form.
Gelatinous zooplankton are fragile animals that live in the water column in the ocean. Their delicate bodies have no hard parts and are easily damaged or destroyed. Gelatinous zooplankton are often transparent. All jellyfish are gelatinous zooplankton, but not all gelatinous zooplankton are jellyfish. The most commonly encountered organisms include ctenophores, medusae, salps, and Chaetognatha in coastal waters. However, almost all marine phyla, including Annelida, Mollusca and Arthropoda, contain gelatinous species, but many of those odd species live in the open ocean and the deep sea and are less available to the casual ocean observer. Many gelatinous plankters utilize mucous structures in order to filter feed. Gelatinous zooplankton have also been called Gelata.
Opisthoproctus soleatus is a species of fish in the family Opisthoproctidae. It was first described in 1888 by Léon Vaillant. The species lives in most tropical seas, but is more common in the eastern Atlantic, from western Ireland to Mauritania and from Sierra Leone to Angola, and also in the South China Sea. O. soleatus can grow to a standard length of 10.5 centimetres (4.1 in) and usually live from about 500 to 700 metres deep.
Flashlight fish is a common name for several fish and may refer to:
Benthosema glaciale, or glacier lantern fish, is the most common species of lanternfish and important part of the midwater ecosystem of northern North Atlantic.
Notoscopelus bolini is a species of lanternfish in the family Myctophidae. It is found in the North Atlantic Ocean and the Mediterranean Sea. It was first described in 1975 by the American ichthyologist Basil Nafpaktitis and named in honour of the American marine biologist Rolf Ling Bolin who had reviewed the genus in 1959.
Lampadena speculigera is a species of lanternfish in the subfamily Lampanyctinae. It is a mesopelagic fish that is found in the Atlantic, Indian, and Pacific Oceans. Its vernacular name is mirror lanternfish.
The headlight fish is a species of lanternfish in the family Myctophidae. It is also sometimes referred to as the headlight lanternfish, or even the lanternfish, though it is not the only species to be called this.
A micronekton is a group of organisms of 2 to 20 cm in size which are able to swim independently of ocean currents. The word 'nekton' is derived from the Greek νήκτον, translit. nekton, meaning "to swim", and was coined by Ernst Haeckel in 1890.
The white-spotted lantern fish, also called Rafinesque's lanternfish, is a species of fish in the family Myctophidae.
