Yellow Edged Moray Eel- Facts and Photographs

yellow-edged moray eel (Gymnothorax flavimarginatus)

 

The yellow-edged moray (Gymnothorax flavimarginatus) is also known as the yellow margin moray eel. They are one of the larger moray eels. As they are nocturnal they are not commonly seen in the open.

APPEARANCE

The yellow edged  moray eel is a dark brown color with irregular yellow markings. The head is large and it has fairly long rear facing teeth for gripping prey. The iris is a yellow or orange color. They have a black blotch in the gill area.They do not have pectoral or pelvic fins and the dorsal fin runs the length of the body. They grow up to 2.4 meters in length and the eel in the video below is about that size.

Toxins

Some researchers speculate that moray eels contain toxins in their mouths and are poisonous.From many years of catching crayfish on the Kwa Zulu Natal coast I have never had a bite go sceptic. After every bite I have soaked the bite area in hot water as hot as I can take it. Much of the bite damage occurs when one pulls ones hand back after being bitten. Many experts say that one should not pull back, however they should go try it themselves. The bite is usually sudden and unexpected and it is natural to pull away from it.  I have personally seen one diver who lost the use of his thumb from a giant moray bite but that is unusual.

Morays secrete mucus over their scaleless skin, which in some species contains toxins. They have a thick skin and a large number of cells that secrete  mucus epidermis. Moray eels have proportionately small  circular gills, located on posterior of the mouth and the moray is constantly opening and closing its mouth to facilitate sufficient water flow over its gills. In general the opening and closing of the mouth is not threatening behavior but one should not approach too closely. They will bite if threatened.

yellow-edged moray eel (Gymnothorax flavimarginatus)

IN THE WILD

The yellow edged  moray eel are generally seen protruding from a hole or small cave during the day.  They are sometimes seen out on the reef at night. The larger specimens are fairly aggressive as can be seen in the video below. They can deliver a fearsome bite and can knot themselves and run the knot up the body to push against the prey, providing additional force to rip pieces of the prey off.

Moray eels have proportionately small  circular gills, located on posterior of the mouth. As a result the moray is constantly opening and closing its mouth to facilitate sufficient water flow over its gills. In general the opening and closing of the mouth is not threatening behavior but one should not approach too closely.

yellow-edged moray eel (Gymnothorax flavimarginatus)

 

HABITAT

The yellow edged moray eel is found across the Indian ocean and in the Pacific.

DIET

The yellow edged moray eel is carnivorous, and does most of its hunting at night. They feed mainly on  fish and crustaceans. As with most other morays they will probably feed on carrion if the opportunity presents its self.

Moray eels have a second set of toothed jaws in their throat called pharyngeal jaws. When feeding, morays latch onto the prey with their outer jaws. They then push their pharyngeal jaws, which are set back in the pharynx, forward into the mouth. These jaws then grasp the prey and pull it back into the stomach. Moray eels are the only fish that use pharyngeal jaws to capture prey. Their main hunting tool is their excellent sense of smell which makes up for their poor eyesight.

yellow-edged moray eel (Gymnothorax flavimarginatus)

 

REPRODUCTION

Studies have shown hermaphroditism in morays, some being sequential and others  synchronous which can reproduce with either sex. Courtship usually occurs when water temperatures are high. After posturing to each other they wrap their bodies around each other and simultaneously release sperm and eggs. Once they hatch the larvae float in the ocean for around 8 months before becoming elvers and eventually a moray eel.

COMMERCIAL EXPLOITATION

 Ciguatoxin, the main toxin of ciguatera, is produced by a toxic dinoflagellate and accumulated up through the food chain, of which moray eels are top. This makes them potentially dangerous for humans to eat. They are fished and do take bait but because of the toxins should not be eaten. There are recorded cases of poisoning from eating the yellow edged moray.

Once caught they are extremely troublesome to deal with. They wrap around the line and secrete a large amount of mucus and as a result the line has to be changed. As with the mucus from puffer fish, no other fish will bite on the line once it has the mucus on it. It is not uncommon for a caught moray eel to actually bite its self while it is busy wrapping around the line.

yellow-edged moray eel (Gymnothorax flavimarginatus)

AQUARIUMS

The yellow edged moray is not commonly kept in private aquariums.

YELLOW EDGED MORAY  EEL CLASSIFICATION

Kingdom:Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Anguilliformes
Family: Muraenidae
Genus: Gymnothorax
Species:G. flavimarginatus

 

LITERATURE CITED

The Reef Guide fishes, corals, nudibranchs & other invertebrates
East and South Coasts of Southern Africa
Dennis King & Valda Fraser

EQUIPMENT USED

Canon 7D

Ikelite 7D Housing

Twin Ikelite DS 161 Strobes

Flat Ikelite Lens Port

Ikelite Dual Synch Cord 

Ikelite 5.1 inch Port body

 

 

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