Additional Deep Sea Species

All of the species featured on this page are found in the deep sea areas around the British Isles. However, the species featured here are either rare, or relatively obscure and so do not have their own profiles. Scroll down to read through the species, or use the links below to jump to a fish species.

Bean’s BigscaleDeep-sea LizardfishRisso’s LanternfishCut-throat EelGreater ArgentineSlickhead SpeciesLeafscale Gulper SharkKnifetooth DogfishPortuguese Dogfish – Velvet Belly Lanternshark – Sloane’s Viperfish – Spiny Eel Species

Bean’s Bigscale

  • Scientific name: Scopelogadus beanii
  • Size: Up to 15cm in length
  • UK shore caught record: No record stands
  • IUCN Status
    • Global: DD (Data Deficient)
    • Europe: NE (Not Evaluated)
  • Distribution: Found on a worldwide basis in waters at least several hundred metres deep.
  • Feeds on: Small mid-water crustaceans and zooplankton.
  • Description: A small fish which has a large head, taking up between a quarter and a third of its overall length. The head is scaleless but may have marks present, while the rest of the body has is covered in large, loose scales. A single dorsal fin is present and the tail is small relative to the overall size of the fish. The colour is usually dark grey to black.

Bean’s bigscale is a deep-sea species of fish which is usually found at depths of several hundred metres down to over three thousand metres. It is found in the deep sea areas around the British Isles but has a global distribution, being found in the waters off North and South America, Australia and Africa. This species feeds on small crustaceans. Its small size means that it may itself become prey for larger species.

Tarleton Hoffman Bean

Tarleton Hoffman Bean

Bean’s bigscale is of no interest to commercial fisheries, and any which are caught are likely to be discarded at sea as unwanted bycatch. The International Union for the Conservation of Nature (IUCN) classes Bean’s bigscale as a species of Least Concern in European waters, although there is not enough research to make an assessment of stock levels around the world, meaning it is classed as Data Deficient on a global basis, although its population is thought to be stable. Bean’s bigscale are named after Tarleton Hoffman Bean (1846-1916), the American ichthyologist who has eight other species of fish and a genus of lanternfish named after him.

Deep-sea Lizardfish

Lizardfish

  • Scientific name: Bathysaurus ferox
  • Also known as: Bathysaur
  • Size: Generally around 2ft in length when fully grown
  • ICUN Status
    • Global: LC (Least Concern)
    • Europe: LC (Least Concern)
  • Distribution: Found across most of the world in deep sea areas.
  • Feeds on: Thought to be a predator which will attack and eat small fish, squid and deep-water prawn species.
  • Description: Long, eel-like body which is can be brownish, silver or light grey in colour and covered in tough scales. Mouth is very large in relation to the overall size of the fish and is full of long, sharp teeth which may also be present on the tongue. Lower jaw protrudes slightly further than upper jaw.

There are over fifty species of lizardfish across the world and the vast majority of these live in shallow waters. However, the species of lizardfish which are found in UK and Irish waters are very deep sea creatures found at depths of several hundred metres to thousands of metres. For this reason they are poorly known to both anglers and the general public.

Distribution

Deep-sea lizardfish are found in the deepest parts of the sea around the British Isles such as the Rockall Trough and Faroe-Shetland Channel. They are found throughout the North East Atlantic, although they are absent from areas such as the Baltic Sea, Black Sea and the Mediterranean. Their range extends across the Atlantic to the western coastline of the USA and Canada, and they are also found in the Southern Hemisphere off the coasts of South Africa, New Zealand, Australia and South America.

Behaviour

Deep-sea lizardfish are a poorly understood species, although the basic facts about how this species behaves are known. Despite their maximum size being only a few feet in length they are active predators, feeding on small fish, deep water crustaceans and squid. It is thought that deep-sea lizardfish wait on the seabed for smaller creatures to pass by and then launch themselves at their prey in an ambush attack. The sharp teeth of this species are hinged backwards, meaning that prey cannot escape once it is in the mouth of the lizardfish. Despite this predatory nature it is also believed that they will scavenge on dead and rotting fish and other forms of animal matter which fall down to the seabed from the upper levels of the ocean.

Commercial Value

While lizardfish may be caught by deep sea trawls and possibly by longlines they are have no commercial value at all and are likely to be discarded at sea if caught by commercial vessels. They are classed as a species of Least Concern by the International Union for the Conservation of Nature.

Risso’s Lanternfish

Risso's Lanternfish

  • Scientific name: Electrona risso
  • Also know as: Chubby Flashlight Fish, Electric Flashlight Fish
  • Size: Grows to around 8 – 9cm
  • IUCN status
    • Global: LC (Least Concern)
    • Europe: LC (Least Concern)
  • Distribution: Found worldwide in deep waters. Much of the European population is found around the Mediterranean with some populations found around the southern and western parts of the British Isles.
  • Feeds on: Tiny crustaceans and copepods.
  • Description: Large blunt head with upturned mouth and very large eyes. Body is short with small fins and small deeply forked tail. Light emitting photophores are located under the eyes and elsewhere on the body.

Risso’s lanternfish are a species of small deep-sea fish which are found in all of the seas and oceans of the world, with the exception of the polar and arctic regions. They generally live at a depth of at least one hundred metres and can be found all of the way down to several thousand metres.

Antoine Risso

Risso’s lanternfish are a small species, seldom exceeding 9cm in length. They shoal in huge numbers around sea mounts and other underwater features. They emit bio-luminescent light from photophores which are located under their eyes and along their lateral line. This light is thought to be used as a form of communication and allows Risso’s lanternfish to shoal together in great numbers, although it may also play a role in distracting predators. Risso’s lanternfish make vertical migrations where they move upwards from their deep-sea habitat to mid-water during darkness. This may be done to pursue copepods and other tiny mid-water crustaceans which make up the vast majority of their diet, although their vertical migration may also be connected to avoiding predators which are more active at night. Although some species of lanternfish are caught commercially on a very small and specialised basis, Risso’s lanternfish are not targeted by commercial fisheries and have no value as a food fish. They are therefore classed as a species of Least Concern by the International Union for the Conservation of Nature (IUCN).

This species is named after Antoine Risso (1777 – 1845), the French naturalist who also has a species of dolphin named after him.

Cut-throat Eel

Cut-throat Eel

  • Scientific name: Synaphobranchus kaupii
  • Also know as: Kaupt’s Arrowtooth Eel, Long-nosed Eel, Slatjaw Eel, Grey’s Cut-throat Eel
  • Size: Up to 3ft in length
  • IUCN status
    • Global: LC (Least Concern)
    • Europe: LC (Least Concern)
  • Distribution: Distributed worldwide. British populations concentrated in the Rockall Trough and Faroe-Shetland Channel.
  • Feeds on: Scavenger that will feed on dead fish and also eat any other bottom dwelling creatures it comes across such as deep-sea prawns and crustaceans.
  • Description: Elongated, typical eel-like body. Long snout with large, wide-opening mouth filled with sharp teeth. Dorsal fin starts half way back on body. Dark grey to dark purple in colour.

The cutthroat eel is a medium sized eel, growing to around one metre in length. They are found in very deep water across the world. They are classed as abundant in number across most of their range, mostly due to their lack of commercial value.

Distribution

It is a deep sea species, which can be found all of the way down to depths of five thousand metres, although it has been known to live and feed at depths of around five hundred metres. It has a worldwide distribution being found throughout European waters with its range extending across the Atlantic to the coasts of Iceland and Greenland to the coasts of the USA and Canada. This species is also found all around the African continent, in Asian waters (particularly off the coast of Japan) and is also present in the Caribbean Sea and off the coast of South America.

Life Cycle and Feeding

The cutthroat eel is mostly a scavenger, scouring the seabed for pretty much anything it can find. They will eat all manner of bottom dwelling creatures such as deep-water prawns, crustaceans and dead and rotting fish, and may also hunt smaller fish and squid. Cutthroat eels may themselves become prey for larger species, such as deep-sea sharks.

Conservation Status

Cutthroat eels have no commercial value and are not targeted by fishing vessels. They may, however, be caught as bycatch where they will almost always be discarded at sea. Due to its widespread distribution and lack of commercial exploitation the IUCN (International Union for the Conservation of Nature) believe that the population of cutthroat eels is stable across the world and class this species as one of Least Concern.

Greater Argentine

Greater Argentine

  • Scientific name: Argentina silus
  • Also known as: Greater Silver Smelt
  • Size: Up to 2ft in length
  • IUCN status:
    • Global: NE (Not Evaluated)
    • Europe: LC (Least Concern)
  • Distribution: Found throughout the deep water Rockall Trough and Faroe-Shetland Channel, and throughout deep water areas in European and American waters.
  • Feeds on: Krill, plankton and tiny crustaceans, and when fully grown will take small squid and fish.
  • Description: Small, slim fish with streamlined body. Prominent first dorsal fin is high and distinctively shaped with second dorsal fin very small with no rays supporting it. Two anal fins present both set far back on the underside of the body. Tail is deeply forked. Eyes are very large. Colour silvery, sometimes with a yellow/green tinge.

The greater argentine is a relatively small deep sea fish which lives at depths down to around 1500 metres, although it can also be found at just a few hundred metres of depth. They are found in the deep waters of northern Europe, with their range extending across the Atlantic to the waters of Canada and the USA. The greater argentine lives and feeds in large schools on the seabed, feeding on small marine crustaceans and prawns, although they will also take small fish and squid when fully grown. It is thought that the greater argentine cannot reproduce until it is around ten years old and may live for as long as thirty years.

Commercial Value

The greater argentine does have commercial value and is edible, and there is some demand for it as a food fish. However, a significant proportion of the greater argentines which are caught are used as fishmeal. The fact that stocks of this species are under-exploited mean that it could soon be targeted by commercial fishing operations. The IUCN, however, currently classes this species as one of Least Concern in European waters.

Slickhead

Slickheads are a family of fish which contains a large number of species. All are deep-water species and get their name due to the fact that they have no scales on their head or gill covers (they are also sometimes referred to as nakedheads or smooth-heads). The most common species in UK waters is Baird’s slickhead which is found in the deep waters around the Rockall Trough and the Faroe-Shetland Channel, with their distriibuton stretching across the Atlantic in Icelandic, Greenlandic, American and Canadian waters. There are a number of other species of slickhead which are found in the waters around Britain and Ireland. These are similarly limited to very deep-water habitats.

Baird’s Slickhead

  • Scientific name: Alepocephalus bairdii
  • Size: Up to 3ft in length
  • IUCN status
    • Global: DD (Data Deficient)
    • Europe: DD (Data Deficient)
  • Description: Generally dark in colour with a silvery tint to the flanks. Body is covered in scales but scales are absent on the head and gill covers – hence the name of this species. There is a single dorsal fin set two thirds of the way along the body, and a tail fin clearly divided into two sections. Eyes are relatively large and a lateral line of darker scales runs the full length of the body.

Although Baird’s slickhead can be found at depths of several hundred metres they are generally found at over one thousand metres deep over sandy, muddy or other smooth seabeds. They tend to avoid rocky, heavy or broken ground. The life-cycle of this species is poorly understood but it is thought that they will feed on a range of species including jellyfish, comb jellies, deep-water shrimps and other invertebrates and will also take any small fish and squid they can catch. Little is known about their breeding patterns or spawning grounds.

Spencer Fullerton Baird

Spencer Fullerton Baird

Being a relatively small fish Baird’s slickhead is prey for other larger predatory species even when fully grown. Baird’s slickhead are of very limited commercial value and have no mass appeal as a food fish, although they are eaten in coastal communities around the Mediterranean. They are often taken as bycatch in trawls for more commercially valuable deep water fish such as orange roughy or roundnose grenadier. Slickhead and may occasionally be retained to be processed into fishmeal, although they are mostly discarded as bycatch. This species of slickhead is known as Baird’s slickhead after Spencer Fullerton Baird (1823 – 1887), the American author and natural historian and who was the first curator of the Smithstonian Institution.

Leafscale Gulper Shark

Leafscale Gulper Shark

  • Scientific name: Centrophorus squamosus
  • Also know as: Deepsea Spiny Dogfish, Nilson’s Deepsea
    Dogfish
  • Size: Up to 5ft in length
  • IUCN status
    • Global: VU (Vulnerable)
    • Europe: EN (Endangered)
  • Distribution: Found in the deep waters of Europe, Africa and Asia. UK populations restricted to the Rockall Trough and Faroe-Shetland Channel.
  • Feeds on: Fish and squid.
  • Description: Typical shark bodyshape. Two dorsal fins are present, both of which have a noticeable spine at their leading edge, pectoral fins are flat edged and there is no anal fin. Eyes are very large and green in colour, multiple gill slits are present and mouth is full of sharp teeth. Skin is very rough and made up of Y-shaped denticles which look like leaves, hence the name. Colour is usually dark grey to brown.

The leafscale gulper shark is a medium sized member of the shark family, growing up to around five feet in length. It is a deepwater species, generally found between depths of 1000 to 3000 metres, although occasionally it will be found at depths of just a few hundred metres. The leafscale gulper shark is a predator and hunts smaller fish and squid, although its feeding habits are poorly understood.

Distribution

Distibution of the Leafscale Gulper Shark

Worldwide distibution of the leafscale gulper shark.

It is found throughout the world in limited numbers. The UK population is centred around the Rockall Trough and Faroe-Shetland Channel, as these are the only places deep enough to provide the appropriate habitat for this species. However, they are also populations throughout the north east Atlantic, off the western and southern coasts of Africa, and around Australia and New Zealand and off the coasts of China and Japan.

Commercial Value and Conservation Status

The leafscale gulper shark is targeted by deep sea commercial fisheries which use both deepwater trawls and long-lines to catch this species. There is a limited market for its flesh which is salted and sold for human consumption, the fins are made into shark fin soup and the liver is also eaten. The carcasses of leafscale gulper sharks may also be sent to fish processing plants to be made into fishmeal. The IUCN (International Union for the Conservation of Nature) currently classify the leafscale gulper shark as Vulnerable with a declining population trend on a global basis and Endangered in European waters. Like most shark species the leafscale gulper shark is a late maturing species with a long lifespan, meaning that numbers will take a very long time to increase even if the commercial fishing pressure on this species reduces.

Knifetooth Dogfish

Knifetooth Dogfish

  • Scientific name: Scymnodon ringens
  • Size: Grows to around 3ft in length
  • ICUN Status
    • Global: DD (Data Deficient)
    • Europe: LC (Least Concern)
  • Distribution: Found in very deep water around the British Isles with its range extending throughout the North Atlantic.
  • Feeds on: Unknown.
  • Description: Thick and stout body with short snout. Mouth is full of sharp and distinctive teeth which give this species its name. Body is generally dark grey to blackish with large greenish eyes.

The knifetooth dogfish is a deep water species of shark. It is found predominantly in European waters. It is a species which is little understood by scientists and marine biologists.

Distribution

The Knifetooth dogfish is found in the waters around Europe and northern Africa.

The knifetooth dogfish can be found in deep water all around the British Isles. Its main distribution is around the Rockall Trough to the west of Ireland and the Faroe-Shetland Channel off the northern coast of Scotland. Its range extends along the Atlantic coasts of Spain and France and along the coast of Portugal, although it is not found in the Mediterranean. It is found along the western coast of the African continent as far as Senegal.

Life Cycle and Feeding

Knifetooth dogfish are thought to live at depths of at least several hundred metres, and can be found down to depths of over 2000 metres. As the knifetooth dogfish is so poorly studied it is not entirely clear what it feeds on. It is theorised that its sharp teeth are used to scavenge on the bodies of large sea creatures such as sharks and whales which fall to the seabed, but it is also believed that knifetooth dogfish hunt smaller fish and squid. Little is known about the spawning and reproduction of this species.

Conservation Status

This species is of minimal commercial value. In the vast majority of cases any knifetooth dogfish caught by deep-sea trawlers will be discarded at sea as bycatch. However, in a small number of cases this species may be retained and processed into fishmeal. There is very little information available on the numbers of this species but – like most deep-sea species – knifetooth dogfish are slow-growing and late-maturing, meaning that they are vulnerable to their numbers being depleted. The International Union for the Conservation of Nature does not currently have enough information to assess the conservation status of this species, meaning it is classed as Data Deficient globally, and Least Concern in Europe.

Portuguese Dogfish

Portugese Dogfish

  • Scientific name: Centroscymnus coelolepis
  • Also know as: Portuguese Shark
  • Size: Up to 4ft
  • UK minimum size: N/a
  • UK shore caught record: N/a
  • ICUN Status
    • Global: NT (Near Threatened)
    • Europe: EN (Endangered)
  • Distribution: Found down to depths of 4000 metres. British Isles populations are concentrated around the very deep water Rockall Trough and Faroe-Shetland Channel.
  • Feeds on: Mostly fish and squid, although will also scavenge on seabed for other sources of food.
  • Description: Thick body. Two small dorsal fins are present with very small spines at the leading edge. Other fins are also relatively small. Eyes are large and appear green. Snout is short and mouth full of small rows of sharp teeth. Colour generally dark brown to blackish.

A small shark species growing to around 3 – 4 feet in length, the Portuguese dogfish is the deepest living of all the shark species, being found at depths of several thousand metres. It is targeted by fisheries and numbers of this species – particularly in Europe – have declined significantly in recent decades.

Distribution and Feeding

Worldwide distribution of the Portuguese dogfish

Worldwide distribution of the Portuguese dogfish

The Portuguese dogfish has a fragmented world-wide distribution. It is found on both sides of the Atlantic, from Greenland to the west African coast (with a separate population around South Africa) and along the coastline of the USA and Canada with a much smaller South American population. It is also found in the Indian Ocean from Madagascar to Australia and New Zealand, with another separate stock found around Japan. The Portuguese dogfish is only found in Britain in the Rockall Trough, Faroe-Shetland Channel and a few other locations on the west coast of the British Isles which are deep enough to hold populations of this species.

The Portuguese dogfish is primarily a predator. It will scour around the seabed hunting fish and squid. However, at times they will also scour the seabed for any other sources of food they can find, and will take any crustaceans and prawns they come across, and will also feed on dead and rotting fish.

Commercial Value

Portuguese dogfish have been targeted by fishermen since the earliest years of the twentieth century as their flesh is edible and the liver contains valuable oil. This means that fisheries across the world but particularly in Japan, Portugal and several Mediterranean countries have targeted this species. In addition to this deep-sea trawls which are targeting other species also catch Portuguese dogfish as bycatch.

Portuguese dogfish

A picture from 1908 showing Portuguese dogfish caught on a long line which had been set at 1450 metres.

This has caused populations of this species to plummet, with the IUCN (International Union for the Conservation of Nature) stating that Portuguese dogfish numbers in the north east Atlantic have declined by 80% over the last one hundred years. Today the IUCN class this species as Near Threatened overall, but European populations are classed as Endangered with a decreasing population trend, and the IUCN also warn that current catch levels are unsustainable. The European Union has imposed catch limits, but with Portuguese dogfish still being caught as bycatch the long term outlook for this species, especially in European waters, in uncertain.

Velvet Belly Lanternshark

Velvet Belly Lanternshark

  • Scientific name: Etmopterus spinax
  • Size: Up to 2ft in length
  • UK minimum size: N/a
  • UK shore caught record: N/a
  • IUCN status:
    • Global: LC (Least Concern)
    • Europe: NT (Near Threatened)
  • Distribution: Found in Rockall Trough and Faroe-Shetland Channel, but also elsewhere around the British Isles where the water is deep enough. Also found in deep waters throughout Europe and along the north African coast.
  • Feeds on: Small fish, squid, prawns and crustaceans
  • Description: Small shark species. Lower half of the body is black in colour, with the rest being grey to brown with the fins being light grey/white. Tail is fairly long and first dorsal fin is small with second being higher and longer. A sharp spine is located in front of both dorsal fins. No anal fin is present and the pectoral fins are well developed. Skin is very rough to the touch. Eyes are large and mouth is full of small sharp teeth.

The velvet belly lanternshark is a small species which lives in very deep water. While it can be found at depths of several hundred metres it is much more common at around 1000 metres, and can be found substantially deeper than this. This species has little commercial value but it high levels of bycatch have seen its numbers reduced in European waters.

Distribution

Velvet Belly Distribution

Worldwide distribution of the velvet belly lanternshark.

The velvet belly lanternshark is found throughout the north east Atlantic from the waters of Iceland and Norway (although it is absent from much of the Baltic Sea) all of the way through European waters and along the west coast of Africa all of the way down to South Africa. It is also found in the Mediterranean Sea, although only in limited numbers in the Black Sea.

Life Cycle and Behaviour

Its name comes from the fact that its belly is a dark colour (whereas most other species have a paler underside) and that this species displays a trait known as bioluminescence – the ability to produce light from cells in the skin. Light producing cells are located in the lower half of its body and along the ridges of its dorsal fins. The velvet belly lanternshark is thought to use this ability to light up cells on its body to deter predators and confuse prey. There is a BBC article on the light producing abilities of the lanternshark available by clicking here. Young lanternsharks are thought to feed on krill and very small crustaceans, and as they get older they will begin to hunt prawns, larger crustaceans and small fish and squid, although the size of the prey that this species will hunt is limited by the fact that the velvet belly lanternshark rarely grows longer than 60cm/2ft itself.

Conservation Status

The velvet belly lanternshark is not valuable commercially and is not targeted by commercial fishing vessels. However, it may be inadvertently caught as bycatch by deep sea trawlers or caught on long-lines which have been set for other species. While a small proportion of velvet belly lanternshark bycatch may be retained to be processed into fishmeal the vast majority will be thrown back into the sea dead.

Vevet Belly Hooked

Vevet belly lanternsharks have had their numbers reduced by commercial fishing such as long-lines which are set for other species.

While the IUCN (International Union for the Conservation of Nature) classes the velvet belly lanternshark as a species of Least Concern overall a separate regional assessment has classed this species as one which is Near Threatened in European waters.

Sloane’s Viperfish

  • Scientific name: Chauliodus sloani
  • Also know as: Sloane’s Fangfish, Dannevig’s Dragonfish, Needletooth Fish
  • Size: Up to 20cm in length
  • UK minimum size: N/a
  • UK shore caught record: N/a
    • IUCN Status:
      • Global: LC (Least Concern)
      • Europe: LC (Least Concern)
  • Distribution: Found on a worldwide basis in waters at least several hundred metres deep.
  • Feeds on: Small and immature fish
  • Description: A small fish which has a large head and fang-like teeth which are very large relative to its body length. Long eel-like tapering body with a hugely extended ray fist ray in the dorsal fin and a small forked tail. Bioluminescent scales are present along the blue-silver body.

Sloane’s viperfish is a species which has a worldwide distribution. Due to its deep-sea habitat and the fact it is of little commercial value it has been poorly studied by the scientific community and many aspects of its life cycle are unknown.

Distribution and Habitat

This species is classed as a deep sea fish, being found at depths of several thousand metres. However, there is evidence that Sloane’s viperfish may make vertical migrations to within several hundred metres of the surface during darkness in search of prey. They have a wide distribution, being found across the temperate and sub-tropical seas and oceans of the world. In terms of their distribution around the British Isles they are found in the deep areas of the Atlantic along the west coast of the British Isles.

Feeding and Behaviour

Sloane’s viperfish teeth

Little research has been carried out into the feeding habits of Sloane’s viperfish. They are believed to be predators which use their sharp, fanglike teeth to prey on smaller fish. The teeth are so large (relative to the body size) that the mouth of this species cannot fully close. Indeed, Sloane’s viperfish competes with the common fangtooth to have the record as the species with the largest teeth relative to body size. Sloane’s viperfish are thought to use the extended bioluminescent front ray of their dorsal fin as a lure to attract smaller prey fish close to them in a manner similar to that of an anglerfish, although due to the difficulties of seeing this species feed in the wild this has never been confirmed.

The vertical migrations that Sloane’s viperfish make into shallower water may be linked to moving into areas where small prey fish are more common. Due to their small size Sloane’s viperfish themselves become prey for larger predators such as deep water sharks. Practically nothing is known about how Sloane’s viperfish reproduce, but they may use their bioluminescence to communicate with and attract other viperfish during spawning. They are calculated to have a lifespan of twenty to thirty years.

Species Name

Sir Hans Sloane

Sloane’s viperfish are named after Sir Hans Sloane (1660 – 1753). He was an Anglo-Irish naturalist and medical doctor who left his vast collection of preserved animals, human and animal skeletons, books, manuscripts and illustrations to the nation on his death. This collection formed the basis of the British Museum and also part of the British Library. Several other species of plants and animals are also named after him, as is Sloane Square in London.

Commercial Value

Sloane’s viperfish have no commercial value and commercial fishing vessels do not actively target this species. Any Sloane’s viperfish which are inadvertently caught by trawlers are likely to be discarded as bycatch. However, bycatch levels are not believed to be a threat to this species and their wide distribution and lack of commercial value mean that the IUCN (International Union for the Conservation of Nature) class Sloane’s viperfish as a species of Least Concern both globally and in European waters.

Spiny Eel Species

There are two spiny eel species found in the deep water environments around the British Isles – the shortfin spiny eel (Notacanthus bonaparte) and the snub-nose spiny eel (Notacanthus chemnitzii). There are four other species of spiny eel found elsewhere in the world. Despite being commonly named as eels, and having an eel-like appearance, spiny eels are not true eels at all but are in fact fish species.

Shortfin Spiny Eel

Shortfin Spiny Eel

  • Scientific name: Notacanthus bonaparte
  • Also know as: Bonaparte’s Spiny Eel
  • Size: Up to 30cm
  • UK minimum size: N/a
  • UK shore caught record: N/a
  • IUCN Status:
    • Europe: LC (Least Concern)
  • Distribution: Found in deep-sea waters throughout Europe, particularly the Mediterranean, and deep-sea areas around the British Isles.
  • Feeds on: Small marine invertebrates and crustaceans.
  • Description: Long slender body which tapers to a point with no tail fin present. Dorsal fin consists of only a number of spines rather than a ray fin, while anal fin is larger and runs for approximately half of the body length, terminating in a trailing point. Pectoral fins are very small and eyes are relatively large. Lateral line runs straight along the full length of the body.

While shortfin spiny eels are not common around the British Isles they can be found the in and around the deep-water areas of the Rockall Trough to the west of Ireland and the Faroe-Shetland Channel to the north of Scotland. They are a deep sea species, occasionally found in depths of 200 metres but generally being found in waters at least 600 to 800 metres deep, and can be found at depths greater than 2000 metres.

Shortfin spiny eels are thought to shoal in large numbers and are believed to feed by swimming with their head pointing downwards allowing them to scavenge and forage as they travel across the seabed. They are thought to feed predominantly on the small invertebrate creatures which are found at great depths such as deep-sea prawns, brittle stars, sea anemones and comb jellies. The spiny eel species found in British waters are of no importance to commercial fisheries, although they may be caught as bycatch in commercial deep-sea trawls and discarded at sea. The International Union for the Conservation of Nature classes this as a species of Least Concern in European waters.

Snubnose Spiny Eel

Snubnose Spiny Eel

  • Scientific name: Notacanthus chemnitzii
  • Also known as: Cosmopolitan Spineback
  • Size: Up to 30cm
  • UK minimum size: N/a
  • UK shore caught record: N/a
  • IUCN Status: LC (Least Concern)
  • Distribution: Similar deep-water distribution to the Shortfin Spiny Eel, but much smaller and more restricted population in British waters. Found around Europe, particularly in the Mediterranean. Also found in Canadian and American waters.
  • Feeds on: Mostly small invertebrates and crustaceans.
  • Description: Body is slightly more rounded and deeper than in the Shortfin eel with upturned snout. Similar spiny dorsal fin and larger anal fin, but lateral line is curved over pectoral fins, which are much larger than those of the shortfin. Colour usually greyish to brown.

The other species of spiny eel found in the waters of the British Isles is the snubnose spiny eel, which is distinguished from its shortfin relative by its upturned, pointed snout, smaller mouth and eyes, more rounded body and larger pectoral fins. This species has similar feeding habits and life cycle to the shortfin spiny eel. However, it is less common in British and Irish waters, although on a worldwide basis it may well be more widespread as it is also found in American and Canadian waters, particularly around the Grand Banks and Georges Bank areas. It is of no importance to commercial fisheries and is globally classed as a species of Least Concern by the IUCN.

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