Moray Eel - Muraenidae

Moray eel identification
Moray Eel identification
Family variety
Morays are a large family with around 150 species in total. All individuals have a similar long thin, body shape, but markings and patterns can vary immensely.
Size
Moray eels can range in size from the Golden Moray (Gymnothorax melatremus) measuring just 26cm long to the Giant Moray (Gymnotorax javanicus) that can measure up to 300cm long.
Behaviour
Moray Eels are nearly all nocturnal hunters, feeding at night when their poor eyesight is less of a handicap and their acute sense of smell comes into its own.

They are territorial fish, spending their days resting in a hole sticking their heads out and rhythmically sucking water through their mouths to keep a flow of water passing their gills. They are usually solitary, although they do sometimes share their home with another moray.
Distribution
Moray eels are found throughout the world in both tropical and temperate waters.
Habitat
Morays make their home in a range of underwater environments. Some species use burrows on a sand or mud bottom, some live along rocky shorelines and some seek a home in the rocks and crevices on coral reefs. They are bottom dwelling fish, rarely moving high in the water column.
Diet
Most Morays are opportunistic hunters, feeding at night & making the most of their long slender bodies to reach even the smallest nooks in the reef. They are restricted in the size of their prey as they cannot chew their food, so any prey must be able to fit through their jaws whole. It is though they sometimes go weeks at a time without choosing to eat, although it is not known why they do this.
Reproduction
Our knowledge of the breeding habits of morays is still very limited. A few species have been observed intertwining and releasing pelagic eggs, but it is unknown if this behaviour is replicated throught the family. Small juveniles are pelagic, settling on the substrate at a length of about 50mm depending on the species.
Defences
Moray Eels have sharp teeth and a powerful bite. Their teeth point slightly inwards, making it difficult for something to be released once it is has been bitten. Because of this sharp bite, Moray Eels have few predators, with only very large & hungry fish risking an attack.
Threats
The primary threat to Morays is us. Some larger morays are prized by people as food, however as Moray Eels are very high up the food chain, they often accumulate the poisonous ciguatoxin, making them potentially dangerous to eat.
Did You Know?
Moray eels have a second set of jaws in their throat which also possess teeth.

They are the only animal to use these jaws when feeding, grasping struggling prey and forcing it down their throat.
Intro

Moray eels are a favourite for divers, especially the more colourful and flamboyant family members. They come in a variety of shapes, sizes and patterns & are often encountered on a dive.

They often hide their long, slender bodies in holes and crevices during the day, allowing only their head to protrude.

Because of the position of their gills they must open and close their mouths repeatedly to allow water to pass and facilitate breathing. This behaviour is often mistaken for aggression, but in reality most morays are shy and quick to retreat into their holes. If they feel threatened however, they are capable of inflicting a nasty bite, but only as a last resort.

FACTFILE

speciesSPECIES:   150


sizeSIZE RANGE:   26-300 cm


distributionDISTRIBUTION:

Global. Widespread throughout region.


habitatHABITAT:

Burrows on a sand or mud bottom, along rocky shorelines, or in coral reefs. Moray eels are bottom dwelling fish.


threatsTHREATS:

Few.

Identification tips
  • Elongated fish with a long thin, body perfect for hunting hiding prey

  • Thick leathery skin, usually patterned in stripes or blotches to help them camouflage against the reef.

  • The dorsal, caudal and anal fins are joined together as a continuous fin along the length of the body.

  • Small circular gills next to their mouth, must be repeatedly moved to force water though, allowing the moray to breath.

  • Mouth is also camouflaged on the inside  as they are open much of the time.

  • Large teeth are designed to tear flesh rather than chewing or gripping.

main image credit

Tara North