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Dive Dry with Dr. Bill

#657: Stumped by the Dragon Sea Moth

For my very last dive in the Egyptian Red Sea last month, we drove down from Roots Camp to Serib Kebir, a bit past the town of el Quseir. Unlike many of our shore-based dives in the desert, we did not simply lay a tarp down on the sand and kit up. Serib Kebir is a developed site where many of the dive centers from the area do their check out dives. There were facilities such as COLD fresh water to quench our thirst, and bathrooms when that fluid decided to exit our bodies. This was luxurious compared to nothing but sand and sea!

I descended and was already heading out over the shallow sandy bottom to locate clear water and avoid any sand stirred up by the other divers. However, I was quickly motioned back to see and film a critter that totally stumped me. Now I've dived in the waters off five continents, and logged many thousands of dives in our own waters, but it is still not that unusual for me to witness a new species or behavior. That may have have something to do with my "senior moments." The fish we encountered resembled nothing I could think of other than possibly a gurnard. But it wasn't.

Some of the other Indian Valley SCUBA divers seemed shocked that I didn't know what it was. I guess my reputation is not entirely earned as I may be able to identify just a thousand or so of the estimated two million marine critters out there. Our guide called it a dragonfish and when I looked it up in the field guide for the region, they gave the common name of dragon sea moth (Eurypegasus draconis). I had never even heard of the fish family (Pegasidae) it belonged to!

The next day when we arrived in Luxor and I had Internet service, I e-mailed my old friend Dr. Richard "Murph" Murphy. Dick was formerly Vice President of The Cousteau Society and has dived all over the world on board Cousteau's Calypso and Alcyone. He currently is the head science and education for Jean-Michel's Ocean Futures organization. Murph had never heard of this species either so I sent him a few of the still images I extracted from the video footage. I felt much better knowing that a global marine expert like him was stumped as well.

Members of the sea moth family hardly look like what most people think of when they hear the word "fish." Their bodies are flattened, but there are plenty of flatfish (flounders, halibut, soles, etc.) even in our waters, so that in and of itself is not unusual. However the body is enclosed in thick bony, plates. Now anyone who has had a dinner of sand dabs or halibut probably knows that the skin is soft and even the bones present little problem. The sea moth has strangely modified pectoral fins that almost make it look like a bird. Gurnards and a few other fish exhibit similar structure. Add the long snout of the dragon sea moth and you have something that almost looks like an overweight hummingbird on the ocean floor!

My readers, being very enlightened about the biodiversity of our oceans, are well aware that fish adopt a wide range of strategies for munching (well, the other word... mating... too, but I'm not going there in this column. Sorry). Some like whalesharks and manta rays filter food out of the water. Others, like scorpionfish and angel sharks, lie in wait to ambush unsuspecting prey. Giant sea bass are suction feeders, opening their huge mouths to create a vacuum that draws munchies inside. Kelp bass and barracuda, actively seek out their prey and truly earn the label predator. I'm no fish, but I gobble down everything anyway I can.

The dragon sea moth has its own unusual feeding strategy. It isn't an ambush predator, nor does it swim around in search of food. It uses its fins to "walk" along the bottom in search of something tasty. Their jaws are located below the long snout. They are toothless so they are not of much use in snatching and holding onto their prey. Instead, their highly adapted mouth can form into a tube-like structure to suck in tasty worms and small invertebrates including isopods, copepods and shrimp that live in burrows. Oh, yummy! They will also take the eggs of small, bottom nesting fish like gobies.

Now the thick, bony plates that cover the bodies of these strange fish pose a problem. It's like having body armor or a tight fitting girdle. How can one grow and expand? To accomplish this, the dragon sea moth actually sheds or molts this hard cover every few days. Hmmm... maybe I should find some tight fitting vest that could contain my own growth and keep me trim and youthful looking. Yeah, don't say it... I know it's too late for that. In addition to the protective body covering, the dragon sea moth can apparently change its color to better match its surroundings. If threatened, they can swim but generally don't.

There are just five species in this fish family. It is only found in temperate and tropical waters of the Indo-Pacific region, so if you see one here in California waters you must be peeking into someone's aquarium. They prefer calm, shallow coastal waters with a sand, mud or rubble bottom. A few other tidbits before I close. Sea moths are reportedly monogamous... no "players" among them. There is a fishery for them in some areas of Asia such as the Philippines. No, no one eats them as food but they are used in some traditional Chinese medicines. I'll stick with aspirin. They are also taken for the aquarium trade.

© 2015 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Images of dragon sea moth with hand for size comparison

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