Eels, Or Freshwater Eels (Anguillidae)

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Eels, Or Freshwater Eels (Anguillidae)
Eels, Or Freshwater Eels (Anguillidae)

Video: Eels, Or Freshwater Eels (Anguillidae)

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River eels are common in temperate and tropical waters in the basins of the North Atlantic Ocean, Indian and Western Pacific Oceans. The family has one genus with 19 species of freshwater eels, reaching a length of 1.5-2 m.

European river eel (Anguilla anguilla), photo photograph of fish
European river eel (Anguilla anguilla), photo photograph of fish

European eel (Anguilla anguilla)

The body is elongated, serpentine, covered with very small scales. There are pectoral fins, no ventral fins. The anal opening is far from the head. The tail is somewhat compressed laterally. The mouth is terminal, the jaws are not excessively elongated. Teethsmall, comb-like or bristle-like, in several rows on the jaws and on the vomer, very small teeth on the pharyngeal bones, on the upper pharyngeal bones they are located in a group in the form of an oval. The branchial openings are well separated from each other, on the sides of the body, vertical; internal branchial openings are wide. The language is there. The lips are thick. The frontal bones are paired, not fused together. The opener is fused with the mezetmoid. The palatine-pterygoid bones are well developed, in the form of an oblong plate. There are 7-9 radial elements in the thoracic girdle (up to 11 in young ones). Ribs and intermuscular bones are weak. The lateral line is well developed. Caudal vertebrae without transverse processes.

European eel (Anguilla anguilla), photo photograph of fish
European eel (Anguilla anguilla), photo photograph of fish

European eel (Anguilla anguilla)

Eels can be narrow-headed (males) or broad-headed (females): as puberty approaches, their eyes enlarge, and all eels become narrow-headed (narrow-headed). Adult eels have a brownish back and yellow sides; as puberty approaches, the back darkens, the belly and sides acquire a metallic sheen.

Females live at the bottom of silted rivers and floodplain lakes. Males keep at sea. Adult females descend along rivers to estuaries, where they meet males. They then jointly migrate to spawning grounds in the Sargasso Sea (Atlantic Ocean). Here, at great depths, females spawn. After spawning, females and males die. Eel larvae - leptocephalic, have the shape of willow leaves: their body is transparent, laterally compressed and sharpened in front and behind. Juveniles are transported by the Gulf Stream across the ocean to the shores of Europe. The fry rise into rivers, enter lakes, feed and grow in fresh waters.

Madagascar river eel (Anguilla marmorata), photo photography
Madagascar river eel (Anguilla marmorata), photo photography

Madagascar River Eel (Anguilla marmorata)

Predatory fish that are nocturnal. Ripening eels slide into the sea and go to great depths, where they spawn. Anadromous fish. River eels are the subject of commercial fishing. Their meat is highly prized. Known from the Upper Miocene.

Eels are represented in our fauna by only one species - river eel. This fish has a long serpentine body without pelvic fins. The scales are very small. The dorsal and anal fins are fused with the caudal. In the CIS, it lives mainly in water bodies of the Baltic Sea basin and very rarely in rivers flowing into the Black Sea.

American, or freshwater, eel (Anguilla rostrata), photo photograph of fish
American, or freshwater, eel (Anguilla rostrata), photo photograph of fish

American River Eel (Anguilla rostrata)

Systematics of the Freshwater eels family:

  • Genus: Anguilla Schrank, 1798 = River eels

    • Species: Anguilla anguilla Linnaeus, 1758 = European eel
    • Species: Anguilla australis Richardson, 1841 = Australian river eel
    • Species: Anguilla bengalensis Gray, 1831 = Bengal river eel
    • Anguilla bicolor McClelland, 1844 = Bicolored river eel
    • Species: Anguilla celebesensis Kaup, 1856 = Celebes river eel
    • Anguilla dieffenbachii Gray, 1842 = New Zealand long-finned river eel
    • Species: Anguilla interioris Whitley, 1938 = New Guinea River Eel
    • Species: Anguilla japonica Temminck & Schlegel, 1846 = Japanese river eel
    • Species: Anguilla luzonensis Watanabe, Aoyama & Tsukamoto, 2009 =
    • View: Anguilla malgumora Kaup, 1856 =
    • Species: Anguilla marmorata Quoy & Gaimard, 1824 = Madagascar River Eel
    • Species: Anguilla megastoma Kaup, 1856 = Large-toothed river eel
    • Species: Anguilla mossambica Peters, 1852 = Mozambican river eel
    • Species: Anguilla nebulosa McClelland, 1844 = African river eel
    • Species: Anguilla nigricans Chu & Wu, 1984 =
    • Species: Anguilla obscura Günther, 1872 = Pacific short-finned river eel
    • Species: Anguilla reinhardtii Steindachner, 1867 = Queensland river eel, or Reinhard eel
    • Species: Anguilla rostrata = American eel

Literature:

1. Zoology course. B. A. Kuznetsov, A. 3. Chernov, L. N. Katonova. Moscow, 1989

2. N. Svetovidov. Fish of the Black Sea. Moscow-Leningrad, 1965

3.L.S. Berg. Fish of fresh waters of the USSR and neighboring countries. Part 3. Publishing house of the Academy of Sciences of the USSR, Moscow, 1949

4. Commercial fish of Russia. In two volumes / ed. O.F.Gritsenko, A.N. Kotlyar and B.N.Kotenyov.- Moscow: VNIRO publishing house. 2006. - 1280 s. (Volume 1 - 656 p.).

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