Eel Featured in Perth 'Reef' Series

In 2010 Perth Mint in Australia issued the last coin in its highly desirable “Reef” fish series of five coins depicting a tessalate moray eel (Gymnothorax favagineus) in full color. In this article I want to tell you about moray eels in general and what little specific information exists about the tessalate moray eel. The five animals in the series (all 50 cents denomination) are the lionfish (KM-1100), leafy sea dragon (KM-1101), clownfish (KM-1328), big belly seahorse (KM-1329) and the above eel. An article on the lionfish was published in World Coin News in 2009 (Vol. 36, No. 6) before the Australian coin was issued, so I will not write about this species again. Upcoming articles will include the leafy sea dragon and big belly seahorse.



Moray Eels

The moray eel family contains 15 genera and about 200 species. They dwell mostly in tropical coral reefs, and at least one species lives in fresh water in Australia. Some live in temperate waters. The California moray lives in temperate waters. The largest moray in terms of body mass is the giant moray eel (Gymnothorax javanicus) that is up to 10 feet long and weighs up to 80 pounds. The longest one is the slender giant moray (Strophidon sathete) that can reach 13 feet. The smallest moray may be the Synder’s moray (Anarchias leucurus) that is about 4.5 inches long. All three species occur in the Great Barrier Reef, Australia.

Moray’s dorsal fin begins just back of the head and continues around the tail. They lack pelvic and pectoral fins. Most have quite sharp teeth, even some canines, but a few have flat teeth for crushing shellfish. A large moray can give one an ugly bite. Morays possess a peculiar second set of jaws, also with teeth, called “pharyngeal jaws” that are located in their throat. When an eel grabs prey, these jaws move forward in the mouth cavity, grab the prey and move it down the throat and into the digestive tract. They are the only animals that have this feature.

The gill-openings are small circular-shaped, and in order to respire correctly the mouth must remain open at all times. This is the reason why most photographs show the mouth open. It is not a threat behavior.

Several species are harvested for food, but some species cause ciguatera poisoning, a food-borne illness. It is caused by small single-celled organisms called dinoflagellates that adhere to corals, seaweed and algae in subtropical and tropical waters and that contain toxins. Plant-eating fish consume these and are in turn consumed by carnivorous fish such as morays, barracuda (not the Pacific species), groupers and others. Thus, the toxins move up the food chain, becoming more concentrated. There is no cure for this illness in humans, and it may last 20 years.

People dwelling in southern California, my home, are familiar with “red tides,” which occur when reproducing dinoflagellates increase their numbers to almost unbelievable quantities and turn the ocean a red color. These are dangerous times for many marine animals, and citizens are advised not to eat oysters or clams. So, it is better not to eat morays, in my opinion.

The Moray lives in holes in the sand and among rocks. Its body is covered by a very thick, slimy mucous. It is interesting that this coating also helps to support the walls of holes where they dwell. It picks up sand grains in the mucous, and many are rubbed off onto the walls of its hole, providing a cement-effect. They usually remain hidden in daytime and hunt at night.