Green moray eels, Gymnothorax funebris (Biology, geographic range, and adaptation) – Video

Video credit: Glenda Vélez Calabria (Colombia)     Technical review: Abdel Rahman El Gamal  

This video was taken in mundo marino and te mostramos lo que pasa en el fondo, Colombia

Introduction: The “Green moray eels”, Gymnothorax funebris are also known as “green conger”, “green congo”, “green eel”, and “olive-green moray eel”. They belong to the family Muraenidae. Based on few documents on green moray eels, it is thought their lifespan in the wild is between 8 and 30 years. A single record indicated that a green moray lived 85 years in captivity. They may be found in public aquariums while not recommended for smaller aquariums because of their escaping ability. Even though they are not common as food fish, within their native range they are eaten by some indigenous peoples. However, there is considerable risk of contracting ciguatera poisoning from this species.

Geographic range

Range: Green moray eels, Gymnothorax funebris, occur in the western Atlantic Ocean from New Jersey to Bermuda and the northern Gulf of Mexico, south to Brazil. They are most common throughout the warm waters of the Caribbean Sea and the Bahamas. These eels make small migrations to spawning sites.

Habitats: Green morays are benthic and solitary species found along shallow rocky shorelines (to a depth of 30 m), intertidal areas, coral reefs, mangroves, seagrass beds, and other areas of sandy or muddy bottoms.

Description: Green moray eels, Gymnothorax funebris, are one of the largest of the moray eels. The body of green moray is muscular with a long dorsal fin that extends down the length of the body starting from the head and ending in a short tail fin. On the average, the length of adult green moray is about 180 cm (ranges from 90 – 150 cm) with an average weight of about 13 kg. Green eels can reach about 250 cm of weight up to 29 kg.

Green Moray has no scales and instead has a smooth brown body. The Green Moray’s body is coated with a layer of protective mucus layer of a yellow color that when mixed with the brown or grey color of eel’s skin, results in a green appearance, for which the animal is named. The species does not show sexual dimorphism as both sexes are alike.

Green eels have a large mouth with a single row of sharp, prominent teeth on the bottom jaw and two rows of teeth on the upper jaw. They also have a third row of curved teeth on the roof of the mouth that helps slippery fish go down the throat. Their structure of their jaws allows them to open and close their mouths both horizontally and vertically which permits them to eat very large items.

Adaptations and habits

Swimming: Moray eels swim by undulating their flattened bodies into lateral waves. Their compressed bodies and well-developed dorsal fins increase their swimming efficiency and they can swim background as good as forward.

Sense: These nocturnal hunters have poor eyesight so they use their sense of smell to find prey. Since the nasal apparatus area is longer in this eel than in other fish, their sense of smell is more acute.

Camouflage: The green color of moray eels is a form of camouflage that enables the eels to hide during the day in rocky crevices waiting for prey to swim by before grabbing it.  They forage in open at night.

Respiration: Green eel continually opens and closes their mouths slowly to force water through their gills. This gaping motion is necessary for respiration.

Social arrangements: Moray eels are benthic and generally solitary animals coming together only for spawning. They are normally gentle and curious and are not threat to human. However, they will turn aggressive when defending their territories or when hunting for food. Their bites are painful and dangerous.

Territorialism: Green eels tend to live and occupy a specific reef for many years.

Feeding behavior: Green morays are nocturnal predators with poor eyesight that primarily use their sense of smell to hunt at night for fish, crabs, cephalopods, octopuses, shrimp and other eels. In aquariums and zoos, green morays are often fed live fish, squids and meaty foods.   

Life cycle: Although there is not much is known about the reproduction of green moray eels, it is believed there are common features with moray eels. For the sake of this review, it could be stated that the green moray eels are oviparous meaning their larvae “leptocephalus” that hatch from eggs.

References: Animal Diversity Web, Marine Bio, Wikipedia, Marine Species Identification Portal, Ashland University, Encyclopedia of Life, Fish Base.



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