Pacific viperfish

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Pacific viperfish
Head of a pacific Viperfish 4037.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Stomiiformes
Family: Stomiidae
Genus: Chauliodus
Species:
C. macouni
Binomial name
Chauliodus macouni
T. H. Bean, 1890
Head of the pacific viperfish Head of a pacific Viperfish.jpg
Head of the pacific viperfish

The Pacific viperfish, Chauliodus macouni, is a predatory deep-sea fish found in the North Pacific. [1] [2] It is reported as being either mesopelagic [1] or bathypelagic, with diel vertical migration to shallower waters. [2] The Pacific viperfish is one of the nine different species that belong to the genus Chauliodus, the viperfish. The Pacific viperfish tend to be the largest of the species, [3] typically reaching lengths of up to 1 foot and are considered an example of deep-sea gigantism. The length-weight relationship of the pacific viperfish varies with sex with females tending to be longer and heavier than males. [4]

Contents

Description

The pacific viperfish is classified as one of the most ferocious deep seas fish for its size. They are iridescent dark silver-blue color in life with pale fins. They can also be a light black color with blue fins. The coloration of the Pacific viperfish has what is known as ultra-black skin to reduce the reflection of other bioluminescence surrounding them to better camouflage in the deep sea. This ultra black skin reduces the amount of light reflected from the body of the viperfish which scatters the light using the melanosomes in its skin that are optimized for reduced reflectance. Looking at the mouth and curvature of teeth one can easily recognize the pacific viperfish. [5] The fangs of the pacific viper are abnormally long that its jaw is extended out, so its teeth can fit outside of its mouth. The fangs rest near the viper's eyes. These fangs are the viper's way of killing fish, the viper will swim at high speeds at its prey and impale them in the process. [6] The jaw of the Pacific Viperfish is also hinged in order to fit large sized prey for its size. [7] It also has a loosejaw that improves the closing of the jaw by facilitating faster closing to better capture prey that may be harder to catch. [8] Furthermore, its hinged skull allows it to rotate upwards when looking to attack and, ultimately, swallow a large prey. High speed collisions and force in bites have cause the viperfish to adapt to high impact. The vertebrae that is located right behind its head is used a shock absorber, very similar to an air bag. They are excellent maneuvers in areas that receive significantly less sunlight than uppermost regions. This is accredited to a protein in the rods known as rhodopsin, composed of the transmembrane protein opsin, and retinal. [9] The viperfish lacks a swimbladder and has large amounts of acidic glycosaminoglycans in its gelatinous tissue that are hypothesized to be used as a possible buoyancy mechanism. [10]

Hunting and feeding

Pacific Viperfish are also one of the many deep-sea fishes that migrate vertically to feed on fish at night. [11] This feeding mechanism is referred to as diel vertical migration (DVM).

Viperfish are often caught with empty stomachs. The viperfish's diet consists of fish with myctophids and slender fangjaws being their most common prey. [12]

According to O'Day (1973) luminescent silhouetting may aid the fish in mating, spacing themselves out as they hunt, maintaining conspecific aggregations, warning potential predators of their own formidable size, or perhaps allowing them to escape from predators by temporarily blinding them. These functions, however, remain speculative. [13]

The Pacific viperfish has large photophores that are found on the ventral side, as well as the ventrolateral sides, where they create rows. These photophores present themselves in luminous tissue that is evident on the dorsal and ventral portions of the fish, as well as the fins. This luminescence was described as having a “blue color” by a scientist who had the fish in a tank for 45 minutes before it expired. It was further noted that luminescence could be induced by prodding the fish with a glass rod, which would cause the luminescence to pulse through the body of the fish before returning to its static glow in the ventral region. It was further noted that placing the fish in a weak adrenaline-seawater solution caused luminescence to increase (as would applying a topical adrenaline solution or injecting adrenaline intravenously. There is a simple, un-pigmented type of luminescent organ found in these fish that is found within a gelatinous sheath which surrounds the entire body. [13]

The photophore is found on the dorsal fin of the pacific viper. The photophore uses bioluminescence to produce light to entice a victim. The prey is attracted to the flickering light like a fishing lure. Along with the extended photophore on the dorsal fin, the viperfish also carries photophores on side and underneath its body. The lights underneath provide a camouflage to fish from below. [7] The photophore also serves as a communication tool; it is used by the viperfish to signal a mate or ward off potential rivals in the area. The Pacific viper utilizes the low visibility and darkness to its advantage for hunting tactics. The Pacific viper lies motionless in the darkness and waves its blinking lure over its head waiting on its meal to arrive. Their stomach is quite large, and they have low basal metabolic rates which enables them to go days without food and store up on food. [7] They're composed of many light organs. Specifically, one of their light organs is found on a long dorsal fin which acts as a lure for when searching for prey. Their light organs allow them to attract prey and warn other viperfish of danger.

Reproduction and ontogeny

Little is known on Pacific viperfish reproductions due to the depths it lives at. Due to darkness and limited mates it is best suited that the Pacific viper externally spawn (biology) or oviparous. [2] Females will release eggs into the water which the male will fertilize. The number of eggs and larvae produced by the female is determined by the temperature of the water and concentration of salt. [14] Spawning is believed to occur year-round but with spikes of young larvae during January and March. When an offspring is born it is about six millimeters long. Offspring's are expected to defend themselves until they are mature. [7]

The first two vertebral centra of the Pacific viperfish are replaced with the first epineural and cartilage within connective tissue. The enlarged first epineural ossification is pointed dorsally in both larval and adult fishes. [15] The epural chondrocytes appear and develop after caudal fin flexion has occurred in development. [16]  

Parasite on the Pacific viperfish Parasite170136-fig1 Protosarcotretes nishikawai PART.png
Parasite on the Pacific viperfish

Parasites

The Pacific viperfish has one documented parasite. In 2018, Susumu Ohtsuka, Dhugal J. Lindsay and Kunihiko Izawa described a new genus and species of pennellid copepod, Protosarcotretes nishikawai , from a single ovigerous female infecting a Pacific viperfish collected from the deep-waters of Suruga Bay, Japan. According to the authors, the new genus had the most plesiomorphic states in the first to fourth legs of pennellid copepods. [17] The discovered a parasite attached to the posterior to the right eye of the host fish, and this discovery marked the only documented case of this species. [17]

Captivity

Viperfish are not an endangered species, but they are preyed on by some dolphin and shark species. They are also unable to live in captivity because of the extreme pressure differences within the environment. [18] Pacific viperfish have been recorded living from 15 to 40 years in their natural habitat. A few species have been captured, but only lasted a couple hours before dying.

Related Research Articles

<span class="mw-page-title-main">Deep-sea fish</span> Fauna found in deep-sea areas

Deep-sea fish are fish that live in the darkness below the sunlit surface waters, that is below the epipelagic or photic zone of the sea. The lanternfish is, by far, the most common deep-sea fish. Other deep-sea fishes include the flashlight fish, cookiecutter shark, bristlemouths, anglerfish, viperfish, and some species of eelpout.

<span class="mw-page-title-main">Stomiiformes</span> Order of fishes

Stomiiformes is an order of deep-sea ray-finned fishes of very diverse morphology. It includes, for example, dragonfishes, lightfishes, loosejaws, marine hatchetfishes and viperfishes. The order contains 4 families with more than 50 genera and at least 410 species. As usual for deep-sea fishes, there are few common names for species of the order, but the Stomiiformes as a whole are often called dragonfishes and allies or simply stomiiforms.

<span class="mw-page-title-main">Gonostomatidae</span> Family of fishes

The Gonostomatidae are a family of mesopelagic marine fish, commonly named bristlemouths, lightfishes, or anglemouths. It is a relatively small family, containing only eight known genera and 32 species. However, bristlemouths make up for their lack of diversity with relative abundance, numbering in the hundreds of trillions to quadrillions. The genus Cyclothone is thought to be one of the most abundant vertebrate genera in the world.

<span class="mw-page-title-main">Lanternfish</span> Family of fishes

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.

<span class="mw-page-title-main">Pelagic fish</span> Fish in the pelagic zone of ocean waters

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.

<span class="mw-page-title-main">Viperfish</span> Genus of fishes

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.

<span class="mw-page-title-main">Stomiidae</span> Family of fishes

Stomiidae is a family of deep-sea ray-finned fish, including the barbeled dragonfishes. They are quite small, usually around 15 cm, up to 26 cm. These fish are apex predators and have enormous jaws filled with fang-like teeth. They are also able to hinge the neurocranium and upper-jaw system, which leads to the opening of the jaw to more than 100 degrees. This ability allows them to consume extremely large prey, often 50% greater than their standard length.

<span class="mw-page-title-main">Stoplight loosejaw</span> Genus of fishes

The stoplight loosejaws are small, deep-sea dragonfishes of the genus Malacosteus, classified either within the subfamily Malacosteinae of the family Stomiidae, or in the separate family Malacosteidae. They are found worldwide, outside of the Arctic and Subantarctic, in the mesopelagic zone below a depth of 500 meters. This genus once contained three nominal species: M. niger, M. choristodactylus, and M. danae, with the validity of the latter two species being challenged by different authors at various times. In 2007, Kenaley examined over 450 stoplight loosejaw specimens and revised the genus to contain two species, M. niger and the new M. australis.

<i>Malacosteus niger</i> Species of fish

Malacosteus niger, commonly known as the black dragon fish, is a species of deep-sea fish. Some additional common names for this species include: northern stoplight loosejaw, lightless loosejaw, black loosejaw, and black hinged-head. It belongs to the family Stomiidae, or dragonfishes. It is among the top predators of the open mesopelagic zone. M. niger is a circumglobal species, which means that it inhabits waters ranging from the tropics to the subarctics. Not many studies have been conducted on its feeding habits, but recent research suggests that M. niger primarily feed on calanoid copepods which is a form of zooplankton. Indeed, it appears that M. niger primarily prey on zooplankton despite its apparent morphological adaptations for the consumption of relatively large prey. Another unique adaptation for this species is its ability to produce both red and blue bioluminescence. Most mesopelagic species aren't capable of producing red bioluminescence. This is advantageous because most other species cannot perceive red light, therefore allowing M. niger to camouflage part of itself to its prey and predators.

<span class="mw-page-title-main">Mueller's pearlside</span> Species of fish

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).

<span class="mw-page-title-main">Sloane's viperfish</span> Species of fish

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.

Stomias boa boa, also called the scaly dragonfish or boa dragonfish, is a subspecies of abyssal barbeled dragonfish of the family Stomiidae. It is found at great depths worldwide in tropical to temperate oceans but is absent from the northern Pacific and northwest Atlantic Oceans.

<span class="mw-page-title-main">Viper dogfish</span> Species of shark

The viper dogfish or viper shark is a rare species of dogfish shark in the family Etmopteridae, and the only extant member of its genus. It has been found in the Pacific Ocean off southern Japan, the Bonin Islands, Pacific Ocean off northern Taitung County and the Northwestern Hawaiian Islands. This species inhabits upper continental slopes and seamounts. It may migrate vertically, shifting between bottom waters 270–360 m (890–1,180 ft) deep during the day and upper waters less than 150 m (490 ft) deep at night. A slender, black shark reaching 54 cm (21 in) in length, the viper dogfish can be recognized by its narrow, triangular jaws and well-spaced, fang-like teeth. It also has two spined dorsal fins, dermal denticles with faceted crowns, and numerous light-emitting photophores concentrated on its ventral surface.

<span class="mw-page-title-main">Velvet belly lanternshark</span> Species of shark

The velvet belly lanternshark is a species of dogfish shark in the family Etmopteridae. One of the most common deepwater sharks in the northeastern Atlantic Ocean, the velvet belly is found from Iceland and Norway to Gabon and South Africa at a depth of 20–2,490 m (66–8,169 ft). A small shark generally no more than 45 cm (18 in) long, the velvet belly is so named because its black underside is abruptly distinct from the brown coloration on the rest of its body. The body of this species is fairly stout, with a moderately long snout and tail, and very small gill slits. Like other lanternsharks, the velvet belly is bioluminescent, with light-emitting photophores forming a species-specific pattern over its flanks and abdomen. The ventral photophores are thought to function in counter-illumination, which camouflages the shark against predators and prey. The bioluminescent flank markings may play a role in intraspecific communication.

Vinciguerria lucetia is a species of marine ray-finned fish in the genus Vinciguerria known by the common name Panama lightfish. It is a small bioluminescent fish, with two rows of tiny photophores along its body. It is very abundant in the tropical Indo-Pacific where it makes large vertical migrations each day.

Aristostomias is a genus of barbeled dragonfishes native to the ocean depths in the Pacific, Atlantic and Indian oceans.

<i>Idiacanthus</i> Genus of fishes

Idiacanthus is a genus of barbeled dragonfishes, the larvae of which are noted for exhibiting the Stylophthalmine trait.

Pachystomias microdon, the smalltooth dragonfish, is a species of barbeled dragonfish found in the oceans at depths of from 660 to 4,000 metres. This species grows to a length of 22.1 centimetres (8.7 in) SL. This species is the only known species in its genus.

<i>Neoscopelus macrolepidotus</i> Species of fish

Neoscopelus macrolepidotus, also known as a large-scaled lantern fish, is a species of small mesopelagic or bathypelagic fish of the family Neoscopelidae, which contains six species total along three genera. The family Neoscopelidae is one of the two families of the order Myctophiformes. Neoscopelidae can be classified by the presence of an adipose fin. The presence of photophores, or light-producing organs, further classify the species into the genus Neoscopelus. N. macrolepidotus tends to be mesopelagic until the individuals become large adults, which is when they settle down to the bathypelagic zone.

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.

References

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