Wild Florida–Moray Eels

For decades, moray eels have had a bad reputation that they don’t deserve–even serving as “the bad guy” in the post-Jaws Hollywood thriller The Deep.  In reality, morays are shy and retiring and not dangerous to humans, and don’t go around looking for scuba divers to eat.

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Green Moray Eel

Moray eels belong to the Muraenidae family, which contains about 200 species, found in virtually every tropical coast in the world (one species, Gymnothorax polyuranodon from the Indo-Pacific, is sometimes even found in freshwater). They range in size from the 4.5 inch Snyder’s Moray to the 13 foot Slender Giant Moray. They all have the typical elongated snakelike body typical of marine eels.

All morays are carnivorous, and feed mostly on fish (a few species are adapted to eat crabs and shellfish). They are unusual among all animals in having two separate sets of jaws–one in their mouth like normal, and a second pair, known as “pharyngeal jaws” deep in the back of their throats, made from modified gill arches. When the eel seizes a fish, the pharyngeal jaws are thrust forward into the mouth to grasp the prey with its teeth, then pull it back into the throat to help in swallowing. If the prey is too large to swallow whole, the eel will wrap its body around it and pull it into manageable pieces. Most morays live in rock crevices on the reefs, where they lie patiently in wait for a fish, squid or crab to wander within range. They have small eyes and poor vision, and hunt mainly by scent, mostly at night. However, they seem to be more intelligent and curious than most fish, and will often poke their heads out to examine a passing diver.

A few species live in burrows in the sandy bottom–they use a thick mucus in their skin to bind the sand together and keep the burrow from collapsing. Although morays are not normally aggressive towards humans, they will vigorously defend their shelters and will readily bite any hands that reach inside. When at rest, morays are constantly opening and closing their mouth. Many divers interpret this as a threatening gesture, but in reality the eel is simply using its neck muscles to pull water over its gills to breathe.

There are at least 15 different species of moral eels known to be found around Florida’s coast, but only seven of them are seen regularly–and the most common of these is the Green Moray,Gymnothorax funebris. This species can be found along the Atlantic and Caribbean coast from southern New Jersey down to Brazil, at depths down to 100 feet. It is known in some areas as the Green Conger Eel. At a typical length of 6-7 feet, the Green Moray is one of the largest eel species in the western hemisphere, capable of reaching lengths up to 8 feet and weighing as much as 30 pounds. At such a size, they have few natural predators of their own, though barracudas and large groupers can eat them The Green Moray is not actually green–the body is a dark brownish-blue color, but the yellowish mucus secreted by the skin combines with this to give the fish its bright green color.

Not much is known about the Green Moray’s breeding habits. It is believed that individuals will gather at an unknown spawning site, perhaps in deeper water. In related species of morays, the eggs hatch into small elongated larvae that are almost transparent, which, after reaching a length of about five inches, transform into juveniles that resemble the adults–but no larvae have been yet definitely identified as Green Morays. The larvae apparently swim around until they find a suitable shelter, where they hide and grow, periodically seeking new shelters as they get bigger. As they grow, the juveniles pass through a stage where they are hermaphrodites, with both male and female organs, before one set or the other atrophies and disappears. It is not known whether this is genetic or determined by environment. It is also not known how long Green Morays typically live in the wild, but a captive aquarium specimen is known to have lived to the age of 85.

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