Overview

Brief Summary

The family Anguillidae contains 15 species and 3 subspecies of freshwater eels, all in genus Anguilla. Freshwater eels are found in most tropical and subtropical areas of the world except the east coast of South America, and the unique distribution of eels has been a subject of many biogeography studies to explain their dispersal (Aoyama et al., 1996, 2001; Aoyama and Tsukamoto, 1997; Bastrop et al., 2000; Lehmann et al., 2000; Lin et al., 2001; Tagliavini et al., 1995, 1996; Tsukamoto and Aoyama, 1998). Anguillid eels are catadromous, meaning that they spawn in the ocean, where the new hatchlings (called leptocephalous larvae) eat small particles of plankton and diatoms, but once they grow larger (the glass eel stage), ocean currents carry them to freshwater and estuarine habitats where they live most of their lives, eating a carnivorous diet of fish, invertebrates, and amphibians. Freshwater eels are long-lived, one European eel (A. Anguilla) has been recorded as living for 88 years in captivity. Their life histories are interesting and complicated; leptocephalous larvae were long classified as separate species and even now while adult-larval pairs are match up, much of their life histories is still unknown. Fossil evidence indicates that this family radiated between 100 and 50 million years ago, and recent molecular analyses suggests that they radiated in three groups: an Atlantic group of two species, Oceanic group of three species, and an Indo-Pacific group of 11 species. Freshwater eels are important food fish and have been farmed for centuries. Unagi (the Japanese word for freshwater eel) is a common Japanese meal, and one of the top four types of sushi in the US. Three species are commonly eaten: the Japanese eel Anguilla japonica, the European eel, A. Anguilla and A. rostrata, the American eel and have all suffered extreme population declines from habitat loss, dam construction preventing their migrations, pollution, and overfishing. The Monterey Bay aquarium recommends consumption of freshwater eels as it is an unsustainable fishery. Even though most freshwater eel supplied for eating is farmed (in China), these eel are not bred in captivity, but are instead captured at the glass eel stage and as such put more pressure on eel populations.



(Froese and Pauley 2011; Halpin 2007; US Fish and Wildlife Service Newsroom, 2011; Wikipedia 2011)

  • Aoyama, J., Nishida M., N. Tsukamoto, K. Molecular Phylogeny and Evolution of the Freshwater Eel, Genus Anguilla. Molecular Phylogenetics and Evolution. Volume 20, Issue 3, September 2001, Pages 450–459.
  • Aoyama, J., Tsukamoto, K., 1997. Evolution of the freshwater eels. Naturwissenschaften 84, 17–21.
  • Aoyama, J., Nishida, M., Tsukamoto, K., 2001. Molecular phylogeny and evolution of the freshwater eel, genus Anguilla. Mol. Phylogenet. Evol. 20, 450–459.
  • Aoyama, J., Kobayashi, T., Tsukamoto, K., 1996. Phylogeny of eels suggested by mitochondrial DNA sequences. Nippon Suisan Gakaishi 68, 312–370 (in Japanese).
  • Bastrop, R., Strehlow, B., Ju¨ rss, K., Sturmbauer, C., 2000. A new molecular phylogenetic hypothesis for the evolution of freshwater eels. Mol. Phylogenet. Evol. 14, 250–258.
  • Froese, R. and D. Pauly, Editors. 2011. FishBase: Genus: Anguilla Family: Anguillidae Freshwater eels. Retrieved March 7, 2012 from http://www.fishbase.org/identification/SpeciesList.php?genus=Anguilla
  • Halpin, P. 2007. Unagi: Freshwater “Eel”. Anguilla japonica, A. anguilla, A. rostrata. Seafood Watch, Seafood Report. Monterey Aquarium. Retrieved March 7, 2012 from http://www.montereybayaquarium.org/cr/cr_seafoodwatch/content/media/mba_seafoodwatch_unagireport.pdf
  • Lehmann, D., Hettwer, H., Taraschewski, H., 2000. RAPD-PCR investigations of systematic relationships among four species of eels
  • (Teleostei: Anguillidae), particularly Anguilla anguilla and A. rostrata. Mar. Biol. 137, 195–204.boundary. Proc. Natl. Acad. Sci. USA 100, 1056–1061.
  • Lin, Y.-S., Poh, Y.-P., Tzeng, C.-S., 2001. A phylogeny of freshwater eels inferred from mitochondrial genomes. Mol. Phylogenet. Evol. 20, 252–261.
  • Tagliavini, J., Gandolfi, G., Cau, A., Salvadori, S., Deiana, A.M., Gandolfi, G., 1995. Mitochondrial DNA variability in Anguilla anguilla and phylogenetical relationships with congeneric species. Boll. Zool. 62, 147–151.
  • Tagliavini, J., Gandolfi, G., Deiana, A.M., Salvadori, S., 1996. Phylogenetic relationship among two Atlantic and three Indo-Pacific Anguilla species (Osteichtyes, Anguillidae). Ital. J. Zool. 63, 271–276.
  • Tsukamoto, K., Aoyama, J., 1998. Evolution of the freshwater eels of the genus Anguilla: a probable scenario. Environ. Biol. Fish. 52, 139–148.
  • US Fish and Wildlife Service, Newsroom, 2011. The American Eel. Retrieved March 7, 2012 from http://www.fws.gov/northeast/newsroom/facts.html
  • Wikipedia, The Free Encyclopedia. December 12, 2011. “Anguillidae”. Retrieved March 7, 2012 from http://en.wikipedia.org/w/index.php?title=Anguillidae&oldid=465487749
Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

Supplier: Dana Campbell

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecology

Habitat

Depth range based on 10005 specimens in 23 taxa.
Water temperature and chemistry ranges based on 395 samples.

Environmental ranges
  Depth range (m): -9 - 3417.5
  Temperature range (°C): 0.819 - 28.954
  Nitrate (umol/L): 0.050 - 30.350
  Salinity (PPS): 6.114 - 38.613
  Oxygen (ml/l): 2.113 - 8.276
  Phosphate (umol/l): 0.035 - 2.138
  Silicate (umol/l): 0.885 - 50.947

Graphical representation

Depth range (m): -9 - 3417.5

Temperature range (°C): 0.819 - 28.954

Nitrate (umol/L): 0.050 - 30.350

Salinity (PPS): 6.114 - 38.613

Oxygen (ml/l): 2.113 - 8.276

Phosphate (umol/l): 0.035 - 2.138

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

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
Specimen Records: 259
Specimens with Sequences: 203
Specimens with Barcodes: 193
Species: 25
Species With Barcodes: 23
Public Records: 116
Public Species: 21
Public BINs: 16
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Barcode data: Anguilla sp. HYT2008

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


No available public DNA sequences.

Download FASTA File
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Statistics of barcoding coverage: Anguilla sp. HYT2008

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Specimens with Barcodes: 2
Species With Barcodes: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Barcode data

Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Wikipedia

Anguillidae

The Anguillidae are a family of fishes that contains the freshwater eels. The 19 species and six subspecies in this family are all in genus Anguilla. They are catadromous, meaning they spend their lives in freshwater rivers, lakes, or estuaries, and return to the ocean to spawn.[3] The young eel larvae, called leptocephali, live only in the ocean and consume small particles called marine snow. They grow larger in size, and in their next growth stage they are called glass eels. At this stage they enter estuaries, and when they become pigmented they are known as elvers. Elvers travel upstream in freshwater rivers, where they grow to adulthood. Some details of eel reproduction are as yet unknown, and the discovery of the spawning area of the American and European eels in the Sargasso Sea is one of the more famous anecdotes in the history of Ichthyology (see Eel life history). The spawning areas of some other anguillid eels, such as the Japanese eel, and the giant mottled eel were also discovered recently in the western North Pacific Ocean.

Freshwater eels are elongate with tubelike, snake-shaped bodies. They have large, pointed heads and their dorsal fins are usually continuous with their caudal fins and anal fins, to form a fringe lining the posterior end of the body. They have small pectoral fins to help them navigate along river bottoms. Their scales are thin and soft.

Anguillid eels are important food fish. Eel aquaculture is a fast-growing industry. Important food eel species include longfin eel, Australian long-finned eel, short-finned eel, and Japanese eel. Most eel production historically has been in Japan, Korea and Taiwan, but in recent years the greatest amount of production has been in China.

Seafood Watch, one of the most well-known sustainable seafood advisory lists, recommends consumers avoid eating anguillid eels due to significant pressures on worldwide populations. Several species used as unagi have seen their population sizes greatly reduced in the past half century. Catches of the European eel, for example, have declined about 80% since the 1960s. Although about 90% of freshwater eel consumed in the US are farm-raised, they are not bred in captivity. Instead, young eels are collected from the wild and then raised in various enclosures. In addition to wild eel populations being reduced by this process, eels are often farmed in open net pens which allow parasites, waste products, and diseases to flow directly back into wild eel habitat, further threatening wild populations. Freshwater eels are carnivores and as such are fed other wild-caught fish, adding an additional element of unsustainability to current eel farming practices.[4]

Species[edit]

References[edit]

  1. ^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology 364: p.560. Retrieved 2007-12-25. 
  2. ^ Pl. 661 in Garsault, F. A. P. de 1764. Les figures des plantes et animaux d'usage en medecine, décrits dans la Matiere Medicale de Mr. Geoffroy medecin, dessinés d'après nature par Mr. de Gasault, gravés par Mrs. Defehrt, Prevost, Duflos, Martinet &c. Niquet scrip. [5]. - pp. [1-4], index [1-20], Pl. 644-729. Paris.
  3. ^ McCosker, John F. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 89. ISBN 0-12-547665-5. 
  4. ^ Halpin, Patricia (2007). Seafood Watch: Unagi. Monterey Bay Aquarium. 

Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!