Dive Dry with Dr. Bill

009: Moray Eel

As I was walking past Antonio's Cabaret in my wetsuit the other day, Pete the musician gave me the idea for this week's column by starting to sing "That's a Moray." He must have known I'd just spent the day underwater with one of the very few moray eels I've seen in the Casino Dive Park the past few years.

When I first started diving Catalina waters in the 60's, many of my friends were reluctant to get close to morays. The fear was that they would rush out and clamp onto the diver's arm in a deathgrip, resulting in massive lacerations or even drowning. Some of our dive instructors in that more macho era reinforced that fear with their own stories (fact or fiction). Now, much older and somewhat wiser, I love getting up close and personal with them. It's the only way to really get to know what a moray (not to mention amore) is like. However I get few opportunities to do so in our waters these days, and have to wait until winter when I dive the tropics to see them regularly.

In his great book Probably More Than You Want to Know About The Fishes of the Pacific Coast, fish expert (and humorist) Dr. Milton Love says Catalina and San Clemente Island are loaded with morays. Unfortunately it is a rare event when I encounter them in the Dive Park, and friends who have access to boats have observed them less frequently elsewhere around the island. While not a scientific study, it does raise some concern and Pete may have to paraphrase the old Pete Seeger song "where have all the morays gone, long time passing?" Hopefully it is just some natural oceanographic cycle.

Our species, the California moray, is found from Pt. Conception south along the Pacific coast of Baja California. It prefers rocky reefs and lives in the "nooks and crannies" provided by the rocks down to depths of about 130 feet. These morays grow to a length of about five feet and may live 30 years or more. Dr. Love suggests that the morays in our waters do not reproduce because the water temperatures are too low. It is believed that those around Catalina actually hatch off Baja and drift north as larvae in the ocean currents. Once settled here, their food preferences are quite similar to my own: sushi and sashimi including fish (like the blacksmith which "shelter" in the rocks during the night), octopi, lobster, shrimp, crabs and other delicacies. Morays generally feed at night using their well-developed sense of smell and can be seen swimming out in the open then.

It is true that divers may be bitten by morays (their species name mordax does mean "prone to bite"). However, this usually occurs when hands have been placed carelessly (or, more stupidly, intentionally) near their mouths, or when spearfishermen try to take them. I have sat underwater face-to-face with morays inches away and have not observed a threatening gesture (yet). With their mouths full of sharp teeth, they do present a somewhat fearsome personna as their mouths open and close... but they are only doing so to pass water over their gills to breathe.

The moray pictured with this article provided a special treat for me. I watched it for nearly an hour over a period of several dives last week. The treat was a dozen or more red and white red rock cleaner shrimp (sometimes known as Catalina cleaner shrimp) present in its hiding place. These shrimp clean dead skin, parasites and bits of food off the morays and will also clean lobster and garibaldi. PBS On-Line referred to these shrimp as moray "dental floss" since they will climb into the moray's mouth to get at food particles. The shrimp benefit from the protection provided by the moray... a good example of "mutualism," where two species benefit from interactions with one another. I was able to get a video sequence of one of the shrimp walking across the head of the moray. A few days later the moray had left that crevice, moving to another nearly 20 feet away, but there were still several red rock shrimp with it.

© 2003 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays.

Image caption: Moray eel with red rock cleaner shrimp

This document maintained by Dr. Bill Bushing.
Material © 2003 Star Thrower Educational Multimedia