Morays are true eels (Order Anquilliformes) one of twenty some families, six-hundred plus species; as opposed to all the other so-called “eel-like” groups of fishes (e.g. wolf-eels that are actually blennies, family Anarrhichadidae = spiny eels, Mastacembelidae; and many other non-true-eel groups that have many head lengths into body lengths appearance).

 

There are about 200 species which occur worldwide in tropical and warm temperate seas. Most species are found on coral reefs, but a few occur in estuaries or in turbid water over silty sand bottom. Morays range in size from the white spotted dwarf moray, which attains a maximum length of 18 cm, to the massive giant moray, which may attain 3 m in length and a weight of 70 kg. Most morays measure in at 1.5 m (5 feet) in length.

Stay in touch with Mundo Azul! Sign up to our google group “Mundo Azul International” and receive news about our work and nature conservation in Peru, Web site updates, action alerts, suggestions on how you can participate or help, volunteer opportunities, internship and job openings and much more.

Follow us on Twitter

Become a member of our Facebook group “Mundo Azul International“

Page author: Stefan Austermühle 

 

The body is usually robust (muscular), more compressed towards the tail, with no scales or paired (pectoral and pelvic) fins. The front nostrils are short tubes (except for the ribbon moray which has enlarged, funnel-shaped nostrils) at the front of the snout, and the rear nostrils are located above the front part of the eye; the gill openings are reduced to a small, slit-like hole on each side of the head, about two mouth-lengths behind the corner of the mouth. The dorsal and anal fins are continuous round the tip of the tail.

 

Morays lack scales, caudal, pelvic and pectoral fins, instead locomoting with long, continuous dorsal and anal fins. They secrete a protective mucus over their scaleless skin which contains a toxin in some species.

 

Their scary-looking open-mouthedness is related to their possession of small, restricted gill openings without covers; they’re breathing!

 

Muraenids sport lateral line pores on their protruding heads, but not on the body. Think about this last characteristic. Makes sense for animals that spend most their time with just their head sticking out of cover.

 

Lowfin moray
 

The Lowfin Moray (Gymnothorax porphyreus) is a reddish brown moray upon which yellow marbling and small dark brown spots are superimposed. It grows to a large size of more than 1 meter. The species frequents cool waters of the eastern Pacific off Chile and Peru and is found at Easter Island, the Kermadecs, Norfolk and Lord Howe Islands, and waters of New Zealand, all south of 25°S.

 

Feeding:

 

Morays are primarily night stalkers that ambush a variety of small fish and crustaceans. Frequently, in the late afternoon and at night the powerful hunter/scavengers swim free from the reef to forage for dinner. By day, most species remain hidden completely from view or with only their heads protruding from crevices.

 

Morays have large mouths and powerful jaws with a vice-like grip. The prey is located primarily by smell. As predators morays are opportunistic omnivores, trying to eat most any fish and/or invertebrate slow enough to grab. Gymnothorax species with their sharp pointy teeth are fish eaters. The teeth point backwards to prevent slippery prey from escaping. Their great sense of olfaction is coupled with bad vision.

 

Wound Danger:

 

A few notes here regarding moray bites: A moray eel appears dangerous because it continually exposes its mouth and teeth. This action, however, is not a hostile gesture, but simply the way an eel breathes. The mouth is constantly opening and closing, mechanically pumping the water required for respiration. This water passes over the small, spherical gills, eventually exiting via the gill slits. The gills and gill slits are very small, as the oxygen demands of this rather sedentary fish are not as great as more active species.

 

Generally, morays are not known to be aggressive to divers unless disturbed or frightened. A mistake that some divers make is to use rocky areas as a hand-hold, which may turn out to be home to several moray eels. Such an action may frighten a moray eel to lash out and bite in self-defense. Like many other “dangerous” sea creatures, they usually do not bite unless first provoked.

 

If grasped out of fear, looking for food or accident, a moray will let you go. No, you won’t have to cut off it’s head, geesh. The worst reaction is the most common and dangerous; to jerk your hand back in autonomic reaction, cutting yourself further on the recurved teeth and landscape. The real problem with these bites is secondary infection. Microbes in the water whether associated with the moray’s mouth or not may infect you through any break in your skin, from a bite scratch or puncture. Treat all these seriously:

• Clean
• Disinfect
• Cover &
• Periodically inspect all such wounds.
• If inflammation, pain persists I’d suggest a medical visit.

 

A special trick of the moray is to throw its body into a knot, letting the knot travel forward to or backward from the head. This is a useful strategy that allows the moray to free itself from certain capture. A scientist recently observed an octopus grab a moray about the head. By throwing itself into a movable knot it slipped its body back through the loop to force the octopus’s tentacles off its head. Some moray species are known to use a knotting behavior to break up large prey items.

 

When a moray eel is hooked on a line, it will try to free itself in the same manner. And somehow, in so doing, the eel actually climbs the line, tail first. This maneuver can have terrifying results, as demonstrated by a recorded incident off Palm Beach, Florida. Here three fishermen in a relatively small boat were enjoying an afternoon of fishing until one of them hooked a twelve-foot moray eel. In trying to escape via the knot route, the fish climbed the line. The three men were paralyzed with fear as the gigantic moray came writhing aboard their boat tail first! Without hesitation all three fishermen jumped overboard!

 

Reproduction:

 

Studies of the reproduction of morays have revealed two types of hermaphroditism: most species appear to be protandrous (sequential) hermaphrodites that become mature as males and then later in life change to females; but some species are synchronous (simultaneously male and female) hermaphrodites, with functional ovaries and testes at the same time.

 

During reproduction the moray’s eggs are released into the water where they develop into ribbon-like, transparent larvae that drift with the plankton for up to a year before transferring to the reef floor as miniature eels.

 

Stay in touch with Mundo Azul! Sign up to our google group “Mundo Azul International” and receive news about our work and nature conservation in Peru, Web site updates, action alerts, suggestions on how you can participate or help, volunteer opportunities, internship and job openings and much more.

Follow us on Twitter

Become a member of our Facebook group “Mundo Azul International“

Page author: Stefan Austermühle