The serpent eel or sand snake-eel (''Ophisurus serpens'') is an

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

found in the eastern

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, western

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

, western

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

, western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

and the north-east and west coast of

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

. It is an elongated, slender fish with a length of up to 250 centimetres. It spends the day with its body immersed in the sediment, emerging into the open water at night.

Description

The serpent eel is an elongated slender fish, attaining a length of up to , with a maximum diameter of , although is a more common total length. The long, tapering snout has the upper jaw longer than the lower jaw. The teeth are sharply pointed and are normally visible; the front nostril is halfway between the tip of the snout and the eye, and the hind nostril is protected by a valve and concealed in a groove closer to the eye. The gape extends as far back as the eye, which has an almond-shaped pupil during the day and a circular pupil at night. The branchial opening is small, and is positioned just in front of the short pectoral fins. Both the dorsal fin and the anal fin are long and low, starting well behind the pectoral fins; there are no pelvic fins or tail fin, and the

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

is clearly demarcated. The general colour is pale brownish-green, with dark punctuations on the snout and often with silvery reflections on the flanks; the belly is pale. Juvenile fish have a less elongated snout, and are a silvery colour.

Distribution and habitat

The serpent eel is found in the eastern Atlantic Ocean, where its range extends from Senegal to Portugal, and the Mediterranean Sea. It has also been recorded from other parts of the African coast and the Indian Ocean, as well as from Australia and New Zealand; this disjunct distribution may indicate that two similar species, looking much alike, are involved. It inhabits soft muddy and sandy sediments, mostly on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

, at depths down to about .

Biology

This fish is nocturnal, spending the day immersed in the sediment with just its head projecting. To bury itself, it wriggles its body and works its way into the sediment tail first. It shows marked fidelity to its burrow, having been observed using the same location for more than a month. It is seldom seen by day because of its secretive habits and cryptic colouration. At night it emerges to feed, the diet probably consisting of fish of a suitable size, and crustaceans.

References

External links

* * Serpent Eel @ Fishes of Australia
/small> {{Taxonbar, from=Q2051566 serpent eel Fish of the East Atlantic Marine fish of Africa Fish of the Mediterranean Sea Marine fish of Australia Fish of the North Island serpent eel Taxa named by Carl Linnaeus