Moray eel

Moray eels, or Muraenidae ( ), are a family of eels whose members are found worldwide. There are approximately 200 species in 16 genera which are almost exclusively marine, but several species are regularly seen in brackish water, and a few are found in fresh water. The English name, moray, dates back to the early 17th century, and is believed to be a derivative from Portuguese , which itself derives from Latin , in turn from Greek , ; these are the Latin and Greek names of the Mediterranean moray.

Moray eels, or Muraenidae ( ), are a family of eels whose members are found worldwide. There are approximately 200 species in 16 genera which are almost exclusively marine, but several species are regularly seen in brackish water, and a few are found in fresh water. The English name, moray, dates back to the early 17th century, and is believed to be a derivative from Portuguese , which itself derives from Latin , in turn from Greek , ; these are the Latin and Greek names of the Mediterranean moray.

Anatomy

The dorsal fin extends from just behind the head along the back and joins seamlessly with the caudal and anal fins, with the exception of members of the subfamily Uropterygiinae, which have fins restricted to the tip of the tail. Most species lack pectoral and pelvic fins, contributing to their elongated appearance. Their eyes are relatively small; morays rely mostly on their highly developed sense of smell, while remaining concealed to ambush prey. The body is generally patterned. In some species, the interior of the mouth is patterned as well. Their jaws are wide, framing a protruding snout. Most possess large teeth suited for tearing flesh or grasping slippery prey. A smaller number of species, for example the snowflake moray (Echidna nebulosa) and zebra moray (Gymnomuraena zebra), primarily feed on crustaceans and other hard-shelled animals, and they have blunt, molar-like teeth suitable for crushing. Morays secrete a protective mucus over their smooth, scaleless skin, which in some species contains a toxin. They have much thicker skin and high densities of goblet cells in the epidermis that allows mucus to be produced at a higher rate than in other eel species. This allows sand granules to adhere to the sides of their burrows in sand-dwelling morays, thus making the walls of the burrow more permanent due to the glycosylation of mucins in mucus. Placement of their small, circular gills on their flanks, far behind the mouth, requires the moray to maintain a gape / gulping motion to facilitate respiration.

Feeding behavior

Morays are opportunistic, carnivorous predators, and feed primarily on smaller fish, crabs and octopuses. A spotted moray eel has been observed eating a red lionfish without harm. Groupers, barracudas and sea snakes are among their few known predators, making many morays (especially the larger species) apex predators in their ecosystems.

Cooperative hunting

Reef-associated roving coral groupers (Plectropomus pessuliferus) have been observed recruiting giant morays to help them hunt. The invitation to hunt is initiated by head-shaking. This style of hunting may allow morays to flush prey from niches not accessible to groupers.

Habitat

The moray eel can be found in both fresh and saltwater habitats. The vast majority of species are strictly marine, never entering freshwater. Of the few species known to live in freshwater, the most well-known is Gymnothorax polyuranodon. occupying a live coral reef, located in Sabang, Philippines Within the marine realm, morays are found in shallow water nearshore areas, continental slopes, continental shelves, deep benthic habitats, and mesopelagic zones of the ocean, and in both tropical and temperate environments. Most species are found in tropical or subtropical environments, with only a few species (yellow moray) found in temperate ocean environments. Although the moray eel can occupy both tropical oceans and temperate oceans, as well as both freshwater and saltwater, the majority of moray eels occupy warm saltwater environments, which contain reefs. Within the tropical oceans and temperate oceans, the moray eel occupies shelters, such as dead patch reefs and coral rubble rocks, and less frequently occupies live coral reefs.

Reproduction and lifecycle

The reproductive biology of moray eels remains incompletely understood. Most species are oviparous, with external fertilization occurring in the water column. During spawning, both males and females release gametes simultaneously, and the fertilized eggs are subsequently dispersed by ocean currents. Following fertilization, the eggs develop into leptocephalus larvae, which are transparent and ribbon-like in appearance. These larvae remain in the pelagic zone for extended periods—often up to a year—feeding on microscopic plankton. This prolonged larval phase facilitates wide geographic dispersal prior to settlement in benthic habitats such as coral reefs or rocky substrates, where metamorphosis into juvenile eels occurs. The transition from larva to juvenile involves significant morphological and behavioral changes, including the development of adult pigmentation, body form, and ecological habits. Juvenile moray eels typically adopt the solitary and territorial behavior characteristic of adults. Due to their nocturnal activity and the often inaccessible environments in which reproduction occurs, direct observations of moray eel courtship and spawning behavior are rare. Consequently, their reproductive mechanisms remain one of the least documented aspects of their biology. Environmental factors such as water temperature, photoperiod, and food availability are believed to influence spawning events. Breeding in captivity is infrequent, which further limits opportunities for scientific study of their reproductive cycle.

Taxonomy

File:TakamayuUBf.jpg|Anarchias seychellensis File:FMIB 47184 Gymomuraena vittata, from Cuba.jpeg|Channomuraena vittata File:Echidna nebulosa Réunion.jpg|Snowflake moray (Echidna nebulosa) File:Echida polyzona.jpg|Barred moray (Echidna polyzona) File:FMIB 42381 Enchelynassa vinolentus (Jordan & Evermann).jpeg|Viper moray (Enchelynassa canina) File:Gymnomuraena zebra by NPS.jpg|Zebra moray (Gymnomuraena zebra) File:Laced Moray.jpg|Laced moray (Gymnothorax favagineus) File:Gymnothorax rueppelliae Réunion.JPG|Gymnothorax rueppelliae File:Monopenchelys acuta - pone.0010676.g012.png|Monopenchelys acuta File:Muraena helena swimming v2.jpg|Mediterranean moray (Muraena helena) File:Pseudechidna brummer.jpg|White ribbon eel (Pseudechidna brummeri) File:Ribbon Moray (Rhinomuraena quaesita) (6052858389).jpg|Ribbon eel (Rhinomuraena quaesita) File:Scuticaria tigrina.jpg|Scuticaria tigrina File:Strophidon sathete.jpg|Slender giant moray (Strophidon sathete) File:Uropterygius xanthopterus - 2.JPG|Uropterygius xanthopterus File:Kidako moray.JPG|Kidako moray (Gymnothorax kidako) Moray Eels Grab Prey With Alien Jaws Smith, J.L.B. 1962. The moray eels of the Western Indian Ocean and the Red Sea. Ichthyological Bulletin; No. 23. Department of Ichthyology, Rhodes University, Grahamstown, South Africa.

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