Synonym(s): Muraena anguilla
The adult European eel (<em>Anguilla anguilla</em>) can reach lengths of 1.5 m, is silver in color, and has a long cylindrical body with small slits for gill openings. The lower jaw is slightly longer than the upper jaw. The European eel also has one pair of pectoral fins, no pelvic fins, and no spines on the anal or dorsal fins.
Ecological Threat: European eels present an ecological threat to the American eel (<em>Anguilla rostrata</em>), which is only found in North America. European eels have been recorded to carry a parasitic nematode, <em>Anguillicola crassus</em> capable of causing severe damage to it's host. This parasite infects the swim bladder of the host resulting in acute inflammatory reactions such as fibrosis or fibrotic conglomerates, constriction of the intestine due to scar tissue, and complete rupture of the swim bladder in severe cases. This kind of damage can lead to unsuccessful migration preventing spawning. With eel populations in decline, the spread of this nematode poses further risk to native American eel populations from exposure to infected European eels.
Biology: The European eel has an average life span of 10-20 years with a recorded life span of 85 years in an aquarium habitat. Mature eels are stimulated to swim downstream from freshwater habitats to marine environments and migrate to spawning locations. Females can carry 3 million eggs per 1 kg of body weight. Once the larvae hatch, a period of migration lasting from 2-3 years occurs until the larvae arrives in coastal waters and metamophs into a glass eel stage changing the overall shape resembling that of the adult. Once the eel acquires pigmentation and enters freshwater it is called an elver. Once migration is complete the eel feeds and grows before returning to the ocean for reproduction.
History: The European eel inhabits the Atlantic Ocean from Europe to North America. This eel was originally found in the Atlantic Ocean off the coast of Europe and would migrate to North Africa. It is currently found off the coast of North America due to spawning behavior. The larval eels drift on the ocean currents from the spawning location to the European coasts. This migration takes about 2 years to complete by the larval European eel.
U.S. Habitat: European eels are nocturnal and hunt for food in a variety of habitats from marine, to estuarine, and sometimes even on land. The adult eel spends most of its life in fresh water estuarine habitats, but migrates to the Atlantic Ocean for spawning.
Native Origin: Atlantic Ocean from Scandinavia to Morocco coasts
U.S. Present: The European eel has been recorded on the East coast and spreading south to Florida. Historical data stated the eel was found off the coast of California, but no populations were established due to an overall unfavorable habitat for the European eel. It is difficult to create an exact range map due to unreliable data presented from fishermen uninterested in contributing.
Distribution: Not known to be in Texas.
Eels from the genus <em>Anguilla</em> do not reproduce in captivity and thus have to be captured from the wild for use of food or sale. These eels are capable of traveling long distances and are not easily contained increasing chances of escaping captivity. That being said it is important to ensure eels of this genus are contained if it absolutely necessary to keep in captivity. No current management plans have been set due to the current fragility of the population with overall declining numbers.
Evans, D. W., and M. A. Mattthews. 1999. <em>Anguillicola crassus</em> (Nematoda, Dracunculoidea); first documented record of this swimbladder parasite of eels in Ireland. <em>Journal of Fish Biology</em> 55: 665-668. <br><br> Kettle, James A., and Keith Haines. 2006. How does the European eel (<em>Anguilla anguilla</em>) retain its population structure during its larval migration across the North Atlantic Ocean? <em>Canadian Journal of Fish and Aquatic Science</em> 63: 90-106. <br><br> McCosker, J. E. 1989. Freshwater eels (Family Anguillidae) in California: current conditions and future scenarios. <em>Calif. Fish and Game</em> 75: 4-11. <br><br> Miyai, T., J. Aoyama, S. Sasai, J. G. Inoue, M. J. Miller and K. Tsukamoto. 2004. Ecological aspects of the downstream migration of introduced European eels in the Uono River, Japan. <em>Environmental Biology of Fishes</em> 71: 105-114. <br><br> Williamson, G. R., and O. Tabeta. 1991. Search for Anguilla eels on the West Coast of North America and on the Aleutian and Hawaiian Islands. <em>Japanese Journal of Ichthyology</em> 38(3):315-317. <br><br> Internet Sources <br><br> www.itis.gov/ <br> http://nas.er.usgs.gov/