Gymnothorax funebris
Black moray
(Also: Green cong; Green conger; Green congo; Green eel; Green moray; Olive-green moray eel)

Gymnothorax funebris, green moray eels, can be found in the western Atlantic Ocean, including the Gulf of Mexico and the Caribbean Sea. Typically, these moray eels range as far north as New Jersey and as far south as Brazil. One individual was reported off the coast of Nova Scotia. Experts speculate that this animal had been carried there by the Gulf Stream. The species is most common in the Gulf of Mexico, the Caribbean Sea, the Bahamas, and the Florida Keys. These eels make small migrations to spawning sites. ("Gymnothorax funebris", 2003)

Green morays live in rocky, intertidal areas, coral reefs, mangroves, tidal creeks, harbors, seagrass beds, and other areas over sandy or muddy bottoms. They reside in rock crevices and small caves, usually no deeper than 30 m. ("Gymnothorax funebris", 2003; Moyle and Cech, 1982)

The body of Gymnothorax funebris is long and laterally compressed. This animal has no scales on its dark brown/grey skin, the entirety of which is covered by a yellow mucus. This mucus serves to protect these eels from parasites and bacteria. The yellow color of the mucus, when mixed with the brown or grey color of the eel's skin, results in a green hue, for which the animal is named. Green morays, like all eels, have no pelvic fins and, like all morays, have no pectoral fins. Their dorsal fin runs the length of the body and is continuous with the caudal fin. On the face there are two cylindrical structures- its incurrent nostrils. The excurrent nostrils are marked by simple openings. The teeth are large and smooth-edged. On the upper jaw, there are two rows of teeth, while on the bottom, there is only one. The largest specimen ever recorded was 2.5 m from nose to tail, with a mass of 29 kg. The average individual is estimated to be 1.8 m from nose to tail and have a mass of 13.3 kg. ("Gymnothorax funebris", 2003; Moyle and Cech, 1982; Nelson, 1984)

When the fertilized eggs of green morays hatch, prolarvae emerge. Shortly thereafter the prolarvae transform into leptocephalus larvae, which grow to be between 5 and 10 cm in length. The leptocephalus larva shares a number of morphological characteristics with its adult counterparts: both are long and laterally compressed and their dorsal, caudal and anal fins are continuous. Unlike adults, they have a "gelatinous" consistency and their tissues (with the exception of bone) are transparent.

The leptocephalus larva will undergo its final metamorphosis in open water. The juvenile resembles the mature animal, save that it is smaller in size. Ocean currents disperse the animals after metamorphosis and, once they have reached a permanent habitat, they mature. This process not only involves an increase in size, but two stages of sexual maturity: a hermaphroditic stage as a juvenile (during which individuals posess both male and female sex organs) before a determined male or female stage as an adult. Experts speculate that environment plays a role in the final sex determination, with more stressful environments producing more females. Based on the documented larval development of the European eel,the larval stage of the green moray probably lasts on the order of 2.5 years. ("Gymnothorax funebris", 2003; Bertin, 1957; Moyle and Cech, 1982; Nelson, 1984)

The mating system of Gymnothorax funebris has yet to be described. We do know that fertilization occurs externally and at a spawning site. Based on what is known about European eels (Anguilla anguilla), it is plausible that green morays are promiscuous and that spawning sites are farther from the shoreline than the eel's foraging habitat, between 400 m and 500 m deep. ("Gymnothorax funebris", 2003; Bertin, 1957)

The reproductive habits of Gymnothorax funebris are not well known. There is no record of when these animals spawn, though close relatives are known to spawn in the early months of the year, around January or February. At a given spawning site, millions of eggs are released, but significantly less are fertilized and fewer still (on the order of one in every six million) survive into adulthood. ("Gymnothorax funebris", 2003; Bertin, 1957)

After they have spawned, adult eels leave the area to die or return to their home range. There is no parental involvement after the eggs have been fertilized. ("Gymnothorax funebris", 2003; Bertin, 1957)

The lifespan of Gymnothorax funebris is not well known. There are records of other Anguilliformes with life spans between 8 and 30 years of age in the wild. One captive specimen lived to be 85 years of age. ("Gymnothorax funebris", 2003; Moriarty, 1978)

This species is solitary and nocturnal. Adults are rarely active outside of feeding and spawning. Larvae, however, must migrate from the spawning site to a suitable habitat. Adults activley hunt fish in caves and crevices along coral reefs or shorelines. When an eel encounters a fish too large to swallow whole, it wraps itself around its prey in a characteristic knot, allowing for leverage against the fish. It then tears its prey into smaller pieces, which can be swallowed more easily. The larvae are also active predators of zooplankton. ("Gymnothorax funebris", 2003; Moyle and Cech, 1982)

Because of their solitary lifestyle, these animals rarely have occasion to communicate with conspecifics. Little is known about how they communicate with potential mates. Their senses, the strongest of which is smell, are dedicated to locating food and a spawning site. ("Gymnothorax funebris", 2003; Bertin, 1957)

Gymnothorax funebris is a dietary generalist. It readily consumes most species of fish, so long as they are small enough to swallow whole or can be ripped into manageable pieces. Green morays will also prey on crustaceans and cephalopods. Larvae prey on diatoms, smaller crustaceans, and other zooplankton. ("Gymnothorax funebris", 2003)

As larvae, green morays are eaten by most any animal that consumes zooplankton. As for adults, little information has been recorded about their predators. Presumably, large individuals would have very few natural predators, since they are relatively large and will viciously attack any potential threats. ("Gymnothorax funebris", 2003; Moyle and Cech, 1982)

Very little is known about the role of Gymnothorax funebris in its ecosystem, beyond that it is a top predator. Reportedly, some maintain a mutualistic relationship with gobies, wrasses, and some shrimp, all of which eat microbes off of the eel's skin. ("Gymnothorax funebris", 2003; "Gymnothorax funebris", 2003; "Gymnothorax funebris", 2003)

Green morays are objects of great interest to divers and tourists at coral reefs and other natural habitats. Commercially, they are sold as pets to private aquarists with adequate facilities to keep them. They are also common in public aquaria. Less often, they are sold as food. ("Gymnothorax funebris", 2003)

These animals are feared for their vicious bite. However, it is worth noting that they rarely bite unless provoked. Also, large individuals are potentially ciguatoxic (a common toxin found in large fish between 35 degrees N and 34 degrees S latitude). Some of the eel's prey consume dinoflagellates that produce ciguatoxins. The toxin concentrates as it moves up the food chain. As a result, it is particularly dangerous to humans who eat large top predators from these ecosystems. ("Gymnothorax funebris", 2003; Moyle and Cech, 1982; Nelson, 1984)

Green moray eels are not currently threatened.