Eels are mysterious fish. For the longest time, it was unknown as to where they spawned. Juvenile eels look very different than adults so that people also used to think that they were two different species of fish. Eel can live in fresh as well as salt water. As long as the ground is wet enough, they can move on land. Eels are momentarily threatened by overfishing. Obstacles between fresh and salt water also form a problem. In 2007, the eel was declared as a protected animal species. A European recovery plan has been developed.

The common eel has a fascinating life-cycle; it is a 'catadromous' species, breeding in the sea and migrating to freshwater in order to grow before returning to the sea to spawn (4). It is thought that all European eels spawn in the Sargasso Sea. The larvae, which look like curled leaves and are known as 'leptocephalli', drift in the plankton for up to three years (2), and are carried by the Gulf Stream towards the coasts of Europe (3). They then undergo metamorphosis into young eels; at this stage they are known as 'glass eels' because they are transparent (2). They become darker in colour and start to migrate up freshwater streams in large numbers; they are known as 'elvers' at this time and measure around 50 mm in length (2). The eels, now called 'brown' or 'yellow eels' grow in freshwater (5), with males and females spending 6 to 12 and 9 to 20 years in freshwater, respectively (3). Towards the end of this time, they become sexually mature; they turn a silvery colour and migrate back towards the sea on dark, moonless and stormy nights; during this time they are known as 'silver eels' (5). Upon returning to the sea, the common eel lives in mud, crevices, and under stones (3). Spawning occurs during winter and early spring in the Sargasso Sea (3). This is a very long-lived species with a maximum life span of 85 years (3). This eel is predated upon by birds, including cormorants and gulls, as well as a number of species of fish (3). Remarkably, they can survive out of water for several hours on damp nights; they may travel overland on dark rainy nights (7).

The common or European eel has a very unusual and fascinating life cycle. Adults have long, narrow bodies, with a continuous dorsal, anal and tail-fin (2). The skin is slimy, the lower jaw is longer than the upper jaw, and the scales are tiny or absent (2). The colour of adults depends on their age; they are often brown, black or olive-green with yellowish bellies. Some adults may be silvery (known as 'silver eels'); the lifecycle stages differ greatly in appearance (2).

Inhabits all types of benthic habitats from streams to shores of large rivers and lakes. Naturally found only in water bodies connected to the sea (Ref. 59043). Territorial and solitary species; 'schools' of young eels which are observed from time to time are a mass response to outward conditions and not of active assembling (Ref. 172). Amphihaline (Ref. 51442). Migrates to the depths of the Sargasso Sea to spawn (Ref. 172, 51442). Eel larvae (leptocephali) are transparent ribbon-like. They are brought to the coasts of Europe by the Gulf Stream in 7 to 11 months time (Ref. 51442) and can last for up to 3 years (Ref. 8994). They are transformed into glass eels (6-8 cm length, cylindrical in shape and transparent to slightly pigmented in colour). They enter the estuaries and colonize rivers and lakes (Ref. 11941, 51442); some individuals remain in estuaries and coastal waters to grow into adults (Ref. 88171). The glass eel stage is followed by a long feeding period (from the yellow to the silver eel stage) lasting 6-12 years in males (Ref. 6125) and 9-20 years in females (Ref. 6125). Yellow and silver eels are benthic, found under stones, buried in the mud or in crevices (Ref. 89138). Yellow eels eventually lose their pigmentation, becoming dark dorsally and silver ventrally (called silver eels). Silver eels are also characterized by a clear contrasting black lateral line and enlarged eyes (Ref. 6125). At the end of their growth period, they become sexually mature, migrate to the sea and cover great distances during their spawning migration (5,000-6,000 km); with extensive daily vertical migrations between 200 m at night and 600 m during day time, possibly for predator avoidance (Ref. 89140). Gametogenesis occurs entirely during spawning migration. Average life span is usually 15-20 years (Ref. 88171). Male eels can grow up to 50 cm TL (Ref. 39903). Occurs at temperatures ranging from 0-30°C (Ref. 172). Its food includes virtually the whole aquatic fauna (freshwater as well as marine) occurring in the eel's area, augmented with animals living out of water, e.g. worms (Ref. 172). Best temperature for making eels sexually mature is 20-25°C (Ref. 35388). Sensitive to weak magnetic fields (Ref. 89141, 89142). Their high fat content and benthic feeding habits in continental waters make them vulnerable to the bioaccumulation of pollutants, such as heavy metals and organic contaminants, that may result in organ damage and impaired migration capability (Ref. 82710) and lowered genetic variability (Ref. 82711). Review of information supports the view that the European eel population as a whole has declined in most areas, the stock is outside safe biological limits and current fisheries not sustainable (Ref. 82712). Obvious decreasing of the stocks for all the continental native distribution area (Ref. 40476). Utilized fresh, dried or salted, smoked and frozen; can be fried, boiled and baked (Ref. 9988).

 The common eel is long and snake-like in shape with a tough, slimy skin. The dorsal fin starts on the back some way behind the gill slits and small pectoral fins and runs the length of the body. At the tail the dorsal fin merges with the ventral fin, that runs along the underside of the body. The eel can be black, brown or dark olive green in colour above, paler and yellowish on the underside. Sexually maturing eels become silver rather than yellow.Anguilla anguilla has a complex life history that is poorly understood. It involves migration of mature adults from European rivers and estuaries to the Sargasso Sea in the west Atlantic for spawning, and the subsequent return of juveniles. They metamorphose twice, part of the life cycle spent in fresh water and part in estuarine or full sea water (Whitehead et al., 1986). The adult eels and the returning juveniles (elvers) are commercially fished. The common eel has small eyes and its lower jaw projects from the upper, which distinguishes it from the conger eel, Conger conger. In the common eel the dorsal fin arises about a head's length behind the gill slits and pectoral fins while in the conger eel the fin arises further forward, from just behind the pectoral fins.

Azores Exclusive Economic Zone, Baltic sea, Belgian Exclusive Economic Zone, Black Sea, British Isles, European waters (ERMS scope), Grevelingen, Gulf of Maine, IJsselmeer, Israeli part of the Mediterranean Sea - Eastern Basin, North West Atlantic, Oostende, Oosterschelde, Polish Exclusive Economic Zone, Portuguese Exclusive Economic Zone, Sas van Goes, Schelde estuary, Spanish Exclusive Economic Zone, Swedish Exclusive Economic Zone, United Kingdom Exclusive Economic Zone, Voordelta, Westerschelde, Wimereux, Zeeschelde

Atlantic Ocean: Atlantic coast from Scandinavia to Morocco; Baltic, Black and Mediterranean Seas; rivers of North Atlantic, Baltic and Mediterranean seas (Ref. 172, Ref. 51442). Continuous introductions to Asia and South and Central America. Spawning area in western Atlantic (Sargasso Sea). At least one country reports adverse ecological impact after introduction. Recent genomic DNA studies show that the European eel exhibits isolation by distance, implying that non-random mating and restricted gene flow among eels from different location exists (Ref. 43723). The existence of 3 genetically distinct sub-populations is suggested: a Northern European subpopulation (consisting mainly of the Icelandic stocks); a Western European subpopulation (including the Baltic, the Mediterranean and Black Sea); a Southern sub-population (including stocks of Morocco) (Ref. 43723, 89139). International trade restricted (CITES Appendix II, since 13.5.2009).

Anguilla anguilla is found in all European rivers draining to the Mediterranean, North and Baltic seas, in the Atlantic south to Canary Islands and parts of Mediterranean north Africa and Asia. It very rarely enters the White and Barents seas, but is recorded eastward to the Pechora River in northwest Russia. The species occurs in low abundance in the Black Sea where it migrates east to the Kuban drainage (occasional individuals reach the Volga drainage through canals), in northern Scandinavia and eastern Europe, but 'trap-and-transport' stocking is interfering with natural population numbers (W. Dekker pers. comm. 2007). Large parts of the population remain at sea particularly in the north western Atlantic and Mediterranean. It is also widely stocked in most inland waters of Europe.

The species is thought to breed in the Sargasso Sea in the West Central Atlantic, migrating across the Atlantic from Europe.

The geographic range of adult European eels includes the English Channel and coasts of the Mediterranean Sea and northern Atlantic Ocean from Iceland to Mauritania (Ringuet et al., 2002). Their range also encompasses the Baltic and North Seas, as well as all accessible continental or coastal hydrosystems (Ringuet et al., 2002). In the early spring months, European eels migrate to the Sargasso sea for breeding. Larvae are hatched from the Sargasso Sea and can also be found along the coast of Europe. Silver (juvenile) stage eels of Anguilla anguilla live in tributaries along the European coast.

Biogeographic Regions: palearctic (Native ); atlantic ocean (Native ); mediterranean sea (Native )

Rivers of North Atlantic, Baltic and Mediterranean seas. Continuous introductions to Asia and South and Central America, but not reproducing. Spawning area in western Atlantic (Sargasso Sea). Also distributed along the coast of Europe from the Black Sea to the White Sea

Western and Eastern Atlantic, Baltic Sea, North Sea, Mediterranean Sea, Black Sea, Sea of Marmara: European seas and adjacent watersheds, spawing and larval migration routes to and from the western Atlantic.

Found in the rivers of the North Atlantic, Baltic and Mediterranean Seas; it also occurs along European coasts from the Black Sea to the White Sea in Russia. Spawning takes place in the Sargasso Sea in the western Atlantic (3).

Dorsal spines (total): 0; Analspines: 0; Vertebrae: 110 - 120

The appearance of European eels varies greatly depending on life stage. As leptocephali, European eels are small, leaflike, and transparent (Deelder, 1970). After metamorphosing into the silver stage, European eels appear silvery in color with elongated dorsal and anal fins that are continuous with the caudal fin (Deelder, 1970). European eels lack pelvic fins (Deelder, 1970). Upon full sexual maturation, European eels develop enlarged eyes, lose their ability to feed, and turn green, yellow or brownish in color (Van Ginniken and Thillhart, 2000).

Female eels are generally substantially larger than males. The largest recorded mass of a female eel is 6.599 g (Dekker, van Os and van Willigen, 1998). The maximum published length of a European eel was 133 cm.

Range mass: 6,599 (high) g.

Range length: 133 (high) cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: female larger

Maximum size: 1500 mm TL

50.0 cm TL (male/unsexed; (Ref. 3506)); 133 cm TL (female); max. published weight: 6,599 g (Ref. 39903); max. published weight: 2,850.0 g; max. reported age: 88 years (Ref. 72468)

Elongated, anguilliform body (Ref. 51442), cylindrical anteriorly, somewhat compressed posteriorly (Ref. 6125). Lower jaw slightly longer and projecting (Ref. 6125, Ref. 51442). Gill openings small and vertical, restricted to the sides (Ref. 6125). Elongated dorsal and anal fins, confluent with caudal fin (Ref. 6125, Ref. 51442), forming one unique fin from the anus to the middle of the back with minimum 500 soft rays (Ref. 40476). Dorsal fin origin far behind pectoral fins; anal fin origin slightly behind anus, well back from origin of dorsal fin (Ref. 6125). Pelvic fins absent (Ref. 2196, Ref. 51442). Greenbrown colored (Ref. 51442).

This taxon is one of a number of demersal species in the Seine River system of Western Europe. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton

The Marne and Yonne exhibit the greatest torrential flows, due to the percentage of their courses underlain by impermeable strata, in combination with the river gradients. Although the Loing manifests the highest percentage of impermeable strata of all the tributaries, its low gradient mitigates against torrential velocities. Thus the majority of the Seine and its tributaries exhibit a relaxed generally even flow rate.

Seine water pollutant loads of heavy metals, nutrients, sediment and bacteria are relatively high, especially influnced by wastewater and surface runoff from Paris and its suburbs. Parisian pollutant loadings are noted to be particularly high during periods of high rainfall, not only due to high runoff, but also from the inadequate sewage treatment facilities in periods of high combined wastewater/stormwater flow.

Heavy metal concentrations at Poses weir reveal the following levels: copper, 1.9 milligrams per liter; cadmium, 32 mg/l; and lead, 456 mg/l. Concentrations of zinc are also quite high, making the Seine Estuary one of the most highly contaminated estuaries in the world with respect especially to lead and cadmium. Significant amounts of toxic pollutants are also attached to sediments deposited in the Seine during the last two centuries, including mercury, nickel, chromium, toluene, DDT and a variety of herbicides and pesticides. Downriver from Paris, significant quantites of ammonium are discharged into the Seine from effluent of the Achères wastewater treatment plant.

There are a total of 37 fish species inhabiting the Seine, and another two taxa that are known to have been extirpated in modern times. Two of the largest aquatic fauna known to have lived in the Seine are now locally extinct: the 500 centimeter (cm) long sturgeon (Acipenser sturio) and the 83 cm long allis shad (Alosa alosa).

The largest extant native demersal (species living on or near the river bottom) taxa in the Seine are:

the 133 cm European eel (Anguilla anguilla);

the 150 cm northern pike (Esox lucius);

the 120 cm sea lamprey (Petromyzon marinus); and,

the 152 cm Burbot (Lota lota).

demersal; catadromous (Ref. 51243); freshwater; brackish; marine; depth range 0 - 700 m (Ref. 54218)

Habitat and Ecology

Systems

• Freshwater
• Marine

Depending on the lifestage of the individual eel, European eels can be found in marine, freshwater, and brackish aquatic environments. Typically, the European eel is found in depths of 0-700 m, most often on the floor of the ocean or river in which it is living.

Range depth: 0 to 700 m.

Habitat Regions: saltwater or marine ; freshwater

Aquatic Biomes: benthic ; coastal ; brackish water

Other Habitat Features: estuarine

Occasionally found in Canadian Atlantic waters.Spawning occurs in Sargasso Sea, leptocephali drift for about 3 years across Atlantic to brackish waters, after several years, return migration back to Sargasso Sea.

benthic

Depth range based on 9725 specimens in 2 taxa.
Water temperature and chemistry ranges based on 210 samples.

Environmental ranges
  Depth range (m): -9 - 615
  Temperature range (°C): 3.141 - 21.403
  Nitrate (umol/L): 0.194 - 17.847
  Salinity (PPS): 6.114 - 38.613
  Oxygen (ml/l): 2.113 - 8.276
  Phosphate (umol/l): 0.035 - 1.740
  Silicate (umol/l): 0.885 - 50.947

Graphical representation

Depth range (m): -9 - 615

Temperature range (°C): 3.141 - 21.403

Nitrate (umol/L): 0.194 - 17.847

Salinity (PPS): 6.114 - 38.613

Oxygen (ml/l): 2.113 - 8.276

Phosphate (umol/l): 0.035 - 1.740

Silicate (umol/l): 0.885 - 50.947
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

 The adult eel is most abundant in estuaries and low salinity pools but is also found around the coast in permanent tide pools, on the lower shore and shallow sublittoral. Being nocturnal it is inactive during the day under rocks or weed or in soft sediments.

Part of the common eel's life cycle is spent in the sea, and part in freshwater rivers. It is often common on the shore (2).

Catadromous. Migrating from freshwater to the sea to spawn, e.g., European eels. Subdivision of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.

Observations have shown that scent and taste appear to be more important than sight for foraging purposes (Ref. 172). Smaller individuals feed mainly on insect larvae, molluscs, worms, and crustaceans; subadults on benthic invertebrates and fish (Ref. 51442); larger individuals on other fishes. This species can also be a scavenger, feeding on carcasses. Yellow and silver eels are nocturnal and opportunistic feeding on virtually all small animals they encounter. Cannibalism occurs amongst yellow eels (Ref. 172). Feeding ceases when silver eels start their spawning migration and rely on their lipid reserves for energy. Leptocephali feed on gelatinous zooplankton (e.g. Hydrozoa, Thaliacea and Ctenophora) (Ref. 89143).

European eels have completely different diets during different life stages. No food contents have ever been discovered in the guts of leptocephali, therefore their diet is unknown (Fisheries Global Information System, 2005). Glass eels consume insect larvae, dead fish, and small crustaceans (Sinha and Jones, 1975). Adult eels have a fairly broad diet and eat freshwater, marine, or terrestrial fauna. Their primary food source is aquatic invertebrates, but they will eat essentially any food they can find-- even dead organisms (Sinha and Jones, 1975). European eels are reported to leap out of the water during the winter and feed on terrestrial invertebrates (Deedler, 1970).

Animal Foods: fish; eggs; carrion ; insects; mollusks; terrestrial worms; aquatic or marine worms; aquatic crustaceans; zooplankton

Other Foods: detritus

Primary Diet: carnivore (Insectivore , Eats non-insect arthropods, Molluscivore , Eats other marine invertebrates, Scavenger )

In Great Britain and/or Ireland:
Animal / parasite / endoparasite
Acanthocephalus lucii endoparasitises anterior intestine of Anguilla anguilla

Animal / parasite / endoparasite
metacaria (diplostomula) of Diplostomum spathaceum endoparasitises eye (lens) of Anguilla anguilla

Animal / parasite / ectoparasite
Ergasilus gibbus ectoparasitises gill of Anguilla anguilla

Animal / parasite / endoparasite
Trypanosoma granulosum endoparasitises blood of Anguilla anguilla
Other: sole host/prey

European eels are both a food source and a predator of organisms in their ecosystem. They are consumed by birds and large predatory fish (Deelder, 1970). European eels also act as a host for the nematode Aguillicola crassus which infects the swim bladders of European eels (Deelder, 1970). European eels distribute nutrients between marine and freshwater ecosystems because they migrate between those habitats (Deelder, 1970).

Commensal/Parasitic Species:

• Anguillicola crassus

European eels are preyed upon by larger eels and other fish and fish-consuming birds, such as cormorants (Phalacrocorax) and herons (Ardeidae) (Deelder, 1970). One defense mechanism employed by eels is that they hide under rocks and burrow in the sand, thus avoiding their predators. The coloring of eels at various life stagies (i.e. the transparency of leptocephali, the dark grey to green color of adults, etc.) also serves as camouflage.

Known Predators:

• herons (Ardeidae)
• cormorants (Phalacrocoracidae)
• predatory fish (Actinopterygii)

Anti-predator Adaptations: cryptic

Anguilla anguilla (Anguilla anguilla eel) is prey of:
Lutra lutra
Phalacrocorax carbo
Ardea cinerea
Sterna paradisaea
Platichthys flesus
Podocotyle staffordi
Derogenes varicus

Based on studies in:
Scotland (Estuarine)

This list may not be complete but is based on published studies.

Anguilla anguilla (Anguilla anguilla eel) preys on:
Tanypus punctipennis
Blicca bjorkna
Acerina cernua
Crangon crangon
Nereis diversicolor
Neomysis integer
Corophium volutator
Gammarus
Jaera albifrons

Based on studies in:
Austria, Neusiedler Lake (Lake or pond)
Scotland (Estuarine)

This list may not be complete but is based on published studies.

Worm Cataract. Parasitic infestations (protozoa, worms, etc.)

White spot Disease. Parasitic infestations (protozoa, worms, etc.)

Vibriosis of eel (acute). Bacterial diseases

Vibriosis Disease (general). Bacterial diseases

Trichodinosis. Parasitic infestations (protozoa, worms, etc.)

Triaenophorus Disease (juvenile). Parasitic infestations (protozoa, worms, etc.)

Streptococcal Infection. Parasitic infestations (protozoa, worms, etc.)

Skin Fungi (Saprolegnia sp.). Fungal diseases

Skin Flukes. Parasitic infestations (protozoa, worms, etc.)

Pseudodactylogyrus Infestation. Parasitic infestations (protozoa, worms, etc.)

Pomphorhynchus Infestation. Parasitic infestations (protozoa, worms, etc.)

Podocotyle Disease. Parasitic infestations (protozoa, worms, etc.)

Pleistophora disease. Parasitic infestations (protozoa, worms, etc.)

Neoechinorhynchus Infestation. Parasitic infestations (protozoa, worms, etc.)

Intestinal Ligulosis. Parasitic infestations (protozoa, worms, etc.)

Gyrodactylogyrus Infestation. Parasitic infestations (protozoa, worms, etc.)

Glugea. Parasitic infestations (protozoa, worms, etc.)

Flexibacter Disease. Parasitic infestations (protozoa, worms, etc.)

Fish louse Infestation 1. Parasitic infestations (protozoa, worms, etc.)

Fin-rot Disease (late stage). Bacterial diseases

Enteric Redmouth Disease. Bacterial diseases

Edwardsiellosis. Bacterial diseases

Diphyllobothrium Disease. Parasitic infestations (protozoa, worms, etc.)

Camallanus Disease. Parasitic infestations (protozoa, worms, etc.)

Branchiomyces Disease. Parasitic infestations (protozoa, worms, etc.)

Anguillicola Infestation. Parasitic infestations (protozoa, worms, etc.)

Anchor worm Disease. Parasitic infestations (protozoa, worms, etc.)

European eels sense the environment using their sense of taste. They have been shown to locate necessary amino acids via chemotaxis (Sola and Tongiorgi, 1998). European eels also utilize olfaction, most probably for homing purposes. There is little if any documentation of social communication between eels (Deelder, 1970).

Perception Channels: visual

Catadromous species. When sexual maturity is reached they leave the river. Spawning migrations occur mainly during the second half of the year but have been observed year-round, usually commencing during dark nights (Ref. 172). Maturity is obtained during the spawning migration (Ref. 88171). Actual spawning has never been observed but is believed to occur solely in the Sargasso Sea between March and June (Ref. 89144). After spawning (at 600 m depth) adults die. Sigmund Freud described the testicles of eel (Ref. 72449).

European eels begin their life cycle as eggs on the bottom of the Sargasso Sea. They hatch as leptocephali, leaf-like larvae (Tsukamoto, Nakai and Tesch, 1998). After hatching, larvae spend a maximum of one year migrating to Europe, or occasionally North America, via ocean currents. The larvae will then metamorphose into 'glass eels,' the next stage of the life cycle, and enter estuarine areas. Male glass eels contineu to grow for approximately 6 to 12 years; females for 9 to 20 years (Deelder, 1970). After a final metamorphosis, European eels migrate back to the Sargasso Sea to spawn.

Development - Life Cycle: metamorphosis

The lifespan of European eels is dependent on maturation time because once eels mature and spawn, they die. European eels can spawn as early as 7 years old. The maximum reported age of a European eel in the wild is 85 years (Dekker, van Os and van Willigen, 1998).

Range lifespan

Status: wild: 85 (high) years.

Typical lifespan

Status: wild: 7 (low) years.

Average lifespan

Status: captivity: 55.0 years.

Maximum longevity: 88 years (captivity) Observations: In the wild, these semelparous animals die after first spawning. After transformation from juvenile to adult stage they do not eat and feature elevated corticosteroids while they migrate to the Sargasso Sea to spawn. Preventing migration by keeping animals in captivity significantly extends lifespan. One female called "Putte", generally assumed to be a European eel, died at Halsinborgs Museum in Sweden at about 88 years of age (Caleb Finch 1990). In the wild, animals do not commonly live more than 10-15 years, though it is possible some live up to 30 years (http://www.fishbase.org/).

Upon reaching sexual maturity, European eels migrate from freshwater streams back to the Sargasso Sea in order to spawn and die in the late winter months to the early summer months. European eel males release sperm into the water in which female European eels have already laid eggs, thereby fertilizing the eggs (Horie et al., 2004). Very little is known about the actual spawning mechanism, and time to hatching is variable.

Mating System: polygynandrous (promiscuous)

European eels spawn during the late winter to early spring months. There is little information on their reproduction, but since European eels are closely related to Japanese eels, Anguilla japonica, similar breeding patterns might be assumed. Female A. japonica can lay from 2,000,000 to 10,000,000 eggs, but die soon after spawning (Deelder, 1970). Eel larvae are independent from time of birth until time of death.

Breeding interval: European eels breed only once during their lifetime. Once spawning is complete, European eels die .

Breeding season: European eels spawn in late winter to early spring.

Range number of offspring: 2,000,000 to 10,000,000.

Range age at sexual or reproductive maturity (female): 9 to 20 years.

Range age at sexual or reproductive maturity (male): 6 to 12 years.

Key Reproductive Features: semelparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning; oviparous

European eels invest a substantial amount of energy in reproduction, and die shortly thereafter (Deelder, 1970). Consequently, the only resource that female eels give to their offspring is enough food source to last the egg until hatching. After hatching, the larvae are completely independent and able to find food (Lecomte-Finiger, 1994).

Parental Investment: no parental involvement; pre-fertilization (Provisioning)

Senses help navigate during migration: European eel
 

European eels navigate during long migrations by being sensitive to many different types of stimuli.

   
  "Those specimens that do complete their life cycle use many environmental cues to navigate during their migration. Not only are eels highly sensitive to olfactory stimuli, they also respond readily to small fluctuations in water movements, seismic activity, and even to the minute electrical fields generated by water currents." (Shuker 2001:74-75)
  Learn more about this functional adaptation.

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 11 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.


Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 21
Specimens with Barcodes: 31
Species With Barcodes: 1

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

European eel populations are not currently threatened.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: critically endangered

Classified as Critically Endangered (CR) on the IUCN Red List (1).

Population

Population Trend

Critically Endangered (CR) (A2bd+4bd)

Major Threats

The population of the common eel is threatened at present, and eel stocks have declined in recent years. However, there is currently very little scientific knowledge of this species, which would aid its management. The threats facing the species are unknown, however, pollution, overfishing, habitat degradation, parasite infection and changes in climate have all been forwarded as potential causes of the decline (6).

Conservation Actions

The European Union is currently funding research that aims to halt the decline of the common eel population (6).

fisheries: commercial; aquaculture: commercial; gamefish: yes

European eels thrive on a diet of marine and freshwater fauna, so impact populations of other marine and freshwater organisms (Deelder, 1970). There are no direct adverse effects to humans.

European eels are a popular food source for humans, especially in Europe and Asia. The eels also feed on the eggs of predatory fish such as trout, which keep ecosystems from overpopulation (Deelder, 1970).

Positive Impacts: food ; controls pest population