The undulated moray (Gymnothorax undulatus) is a distinctive moray eel, taking its name from the pattern of light undulating lines that form a faint net-pattern along its long, sinuous body (3)(4). An otherwise dark green to black-brown eel, the head is bright yellow in colour and a conspicuous yellow line runs along the top of the dorsal fin. A thin membrane covers all of the fins and runs around the body from the dorsal fin, round the tail fin to the anal fin(5). As a voracious predator, the undulated moray has large, elongated jaws, with the lower jaw being slightly hooked (3), and the mouth is armed with rows of long, thin, fang-like teeth (6). Like other moray eels, the undulated moray does not have scales, and so to protect itself from parasites and scrapes, it secretes a protective layer of mucus over the thick, muscular body (7).
The undulated moray is a nocturnal species that uses its keen sense of smell to actively and aggressively hunt for fish, octopus and crustaceans, consuming almost anything that will fit in its mouth (2)(3)(6). When prey is captured, it uses a specialised second set of jaws within the throat to grasp onto the prey and drag it back into the throat (8).
Not much is known about the biology of the undulated moray, but in other species of moray eel, the male begins courtship by displaying to a female, before entwining around the female’s body (7). Once pair formation is complete, the female spawns large numbers of heavily-yolked eggs, which are fertilised externally by the male. Small, ribbon-shaped larvae subsequently emerge from the eggs to drift passively in ocean currents as part of the zooplankton community, before growing large enough to establish a territory on a reef (7)(9).
Occurring in coastal areas and around islands in the Indian Ocean and western, central and eastern Pacific Ocean, the greatest density of undulated morays is found throughout south-east Asia, from Indonesia and the Philippines southwards to northern Australia (2).
The undulated moray does not appear to be under any immediate threat of extinction, although it is occasionally targeted by commercial fisheries and is also captured for aquariums or use in traditional Chinese ‘medicine’ (2).
In fish, an unpaired fin on the under surface of a fish, behind the anus.
Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.
The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.
The fusion of gametes (male and female reproductive cells) to produce an embryo, which grows into a new individual.
Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
Active at night.
An organism that derives its food from, and lives in or on, another living organism at the host’s expense.
An area occupied and defended by an animal, a pair of animals or a colony.
Tiny aquatic animals that drift with currents or swim weakly in water.
Sadovy, Y. and Cornish, A.S. (2000) Reef Fishes of Hong Kong. Hong Kong University Press, Hong Kong.
King, D. and Fraser, V. (2001) More Reef Fishes and Nudibranchs. Struik Publishers, Cape Town, South Africa.
Allen, G.R. and Robertson, D.R. (1994) Fishes of the Tropical Eastern Pacific. Crawford House Press Pty Ltd, Bathurst, Australia.
Bohlke, E.B. and Randall, J.E. (2000) A review of the moray eels (Angulliformes: Muraenidae) of the Hawaiian Islands, with descriptions of two new species. Proceedings of The Academy of Natural Sciences, 150: 203-278.
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