
Fig 1

Fig 2
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Order : Anguilliformes
Family : ANGUILLIDAE
Species : 19 species
Maximum Length : up to 200 cm (in female Anguilla marmorata)
As of 2024, there are 20 species of freshwater eels recognised by
Fishbase, of which 9 or 10 occur in Southeast Asia (see Kottelat, 2013
for taxonomic details).
Within Southeast Asia the most widespread species appears to be the Giant
Mottled Eel (Anguilla marmorata), illustrated here. The range of this
species extends from East Africa, through the Indian Ocean and Southeast
Asia to the western Pacific Ocean, including Japan and French Polynesia.
Other species are limited in their range, for example Anguilla borneensis
is endemic to the island of Borneo and Anguilla luzonensis is limited
to a small part of the island of Luzon, in the Philippines.
Freshwater eels are catadromous; as adults they live most of their lives in
freshwater habitats, but when fully mature they migrate to seas and oceans to
breed and subsequently die. Young eels (elvers) then return to rivers,
streams, marshes and lakes to complete the cycle.
Freshwater eels are demersal, which means they live close to the bed of
seas, rivers, streams and lakes. As a result their presence is often
overlooked, especially if there is aquatic plant growth in which to hide.
Smaller eels sometimes conceal themselves beneath rocks.
Some species are plain in colour, typically brownish, greenish or yellowish,
and others are mottled. Their dorsal, tail and anal fins are merged
into a single continuous structure; this feature, and their elongated shape,
makes them fast, strong swimmers. They possess soft scales embedded in their
smooth skin.
Their diet can be variable, but it may include small fishes, molluscs and
crustaceans.
Some species are farmed, most notably the Japanese Eel (Anguilla japonica).
Figs 1 and 2 : Giant
Mottled Eel (Anguilla marmorata) from Rarotonga, Cook Islands; this
species may grow up to 150-200 cm total length.
References :
Kottelat, M., 2013. The fishes of the inland waters of Southeast Asia: a
catalogue and core bibliography of the fishes known to occur in freshwaters,
mangroves and estuaries. The Raffles Bulletin of Zoology 2013 (Suppl.
27):1-663.
Links :
Fishbase
- Anguillidae
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