by B. N. Sullivan
Imagine that you are on a dive boat in the Red Sea. The boat has just tied up to a mooring at a place called Jackson Reef in the Tiran Straits. All geared up, you jump off the stern platform of the boat and begin your descent. As you drift down gently through the water column, something off in the distant blue catches your eye. At first all you can make out is a hulking shape that looks vaguely like a Volkswagen beetle, and it is moving toward you. As it lumbers along, the shape tilts this way and that, and as it gets closer you are able to make out pectoral fins, big eyeballs, and huge fat lips. You realize it's definitely not a Volkswagen; it's a great big fish - A Napoleon Wrasse.
Earlier this week, for Wordless Wednesday, I posted a
photo of a Napoleon Wrasse. Readers commented on the size of the fish, on its shape, and on its prominent eye.
These guys definitely are big: adults usually are close to four feet in length, although I read somewhere that there have been reports of older males of the species occasionally reaching a length of about six feet. Females tend to be smaller. In any case, they are said to be the largest species in the Wrasse (
Labridae) family.
They are heavy-bodied, and weigh several hundred pounds. Because of their bulk, they usually lumber along, but make no mistake - they are capable of very quick speeds, too, at least over short distances.
Their eyes are large, and each can move independently. The eyes protrude and rotate in a way that might remind you of the ball turret on a World War II B-17 aircraft (without the gunner). When they are close to you, they tend to tilt to look at you with one eyeball, much as a chicken would.
The common name, Napoleon Wrasse, arises from the prominent bump that protrudes from the foreheads of fully grown adults, giving them a profile that is reminiscent of Napoleon Bonaparte with his hat. Another common name for the fish is Humphead Wrasse -- take your pick -- but in either case, the scientific designation for the species remains the same:
Cheilinus undulatus.
These fish can live for thirty years or so, and they seem to have long memories. When we first began to dive in the Red Sea a few decades ago, dive guides there sometimes would entertain their clients by hand feeding boiled eggs to the Napoleon Wrasses. After awhile, once everyone finally realized that this was not an ecologically sound thing to do, this practice was banned.
Unfortunately, no one sent a memo to these fish to tell them not to expect boiled egg handouts from divers. For years after the practice of feeding them boiled eggs had stopped, the Napoleons still converged near dive boat moorings as soon as they heard the sound of the boats' engines approaching. There they would lurk until they spotted divers descending, at which point they would approach the divers at quite close range, hoping for a free snack.
Sometimes the Napoleons would do more than wait. If a diver reached into the pocket of his vest for any reason, the Napoleon would quickly swim right up to that diver in anticipation, sometimes nudging the diver with those great big fat lips. We've heard countless of stories of divers who had to physically push a Napoleon away from them repeatedly before the fish finally got the message that they had no eggs to hand out.
In an extreme case that we actually witnessed, a friend who was diving with us lost an important piece of gear to a Napoleon, and almost lost his hand as well.
For the benefit of our non-diving readers, let me first explain that these days, scuba regulators (the device that reduces the pressure of the compressed air in the cylinder so that it can be breathed) usually have two second stages, i.e., the part that includes the mouthpiece. The primary one will be used by the diver to breathe underwater. The secondary one, though fully functional, is a back-up. As such, it is usually attached to the diver's vest by a clip or similar means, or stuffed into a pocket.
So then, on this particular dive, the clip that usually held our friend's back-up second stage had broken. Rather than let the device trail behind him, he held it at waist level, cupped in his two hands, as he swam. Now, these devices come in a wide variety of colors. Our friend's happened to be white. (Can you see what's coming?)
Along came a Napoleon. It saw the round white shape cupped in our friend's hand and apparently mistook it for an egg. First the fish swam back and forth excitedly around our friend. Then it nudged him. Annoyed, our friend put out one hand to push the aggressive fish away. At that instant, the Napoleon lunged and snapped the white regulator out of our friend's other hand -- or tried to. The regulator was attached to a hose, of course. When the Napoleon bit, the hose partly detached and it began to froth like crazy from the rapidly escaping compressed air. That scared the fish, which went zooming past us with our friend's glove hanging from its mouth!
That was the end of that dive: time to initiate emergency procedures. A fourth diver who was with us immediately handed off his back-up second stage to our stricken friend so that he could breathe. Meanwhile, Jerry swam around behind him to turn off the valve on his cylinder, stopping the uncontrolled flow of air. Then, with the two divers sharing air, we all swam back to the boat.
Once on board, we inspected the damage. The hose had to be replaced, and although the white second stage that had been bitten probably could have been repaired, our friend announced immediately that he would replace it -- with a black one! No one ever saw the glove again, but our friend was happy enough to have relinquished it, since he still had his hand.
By the way, we have seen Napoleons elsewhere -- especially in the waters around Malaysia and Indonesia -- but only the ones in the northern Red Sea were so bold. The ones we saw in other places tended to keep their distance from divers. Apparently they had not been fed by divers. In fact a dive guide in Indonesia told us that Napoleons had been a favorite target of spear-fishermen there until quite recently; thus, they had learned to be wary of humans underwater.
About the photos on this page: Each image shows a different individual Napoleon Wrasse, and each was photographed on a different dive. I took all three photos in the Red Sea: the top photo was taken at Jackson Reef in the Tiran Straits; the other two photos were taken at Ras Mohammed, near the tip of the Sinai Peninsula. And in case you are wondering, the Napoleon in the third photo is not about to bite the leg of the diver on the left. It's an optical illusion created by the wide angle lens. The wrasse actually was positioned between the two divers.
Today we present the next example of 'Exotic Underwater Nudies' -- our series on nudibranchs (a.k.a. sea slugs) from around the world. This particular nudibranch lives primarily in the Mediterranean Sea. Its usual common name is the Dotted Sea Slug. Its scientific name is Peltodoris atromaculata -- but it used to be called Discodoris atromaculata. More on this below.
The second photo shows the underside of this creature. (Yes, I flipped it over on purpose so that I could photograph its underpinnings, but I then returned it to its original position before I swam away.) You can see the creature's 'foot' -- the muscular structure that it uses for locomotion -- and you can see how the mantle extends like a skirt to obscure the foot when the animal is in its normal position.
Now, about the name. Regular readers of The Right Blue know by now that we like to give the scientific names of the critters we write about or show in our photos, because common names often vary from one location to the next, and certainly from one language to the next, while the scientific name is standardized: it is the same for a given species across languages and locations. When we know and use a creature's scientific name, we can be sure that we are all talking about the same thing.
[Click on the photo to enlarge.]
For the past few months, virtually all of our posts here on The Right Blue have focused on interesting species of marine life we have come to know. Feedback on those articles has been positive: our readers seem to enjoy learning about creatures that inhabit the sea. But we also have been nudged by a few readers to get back to writing about diving -- as in, "Enough with the critters, already. Get back to diving stories!"
The best way to prevent many of these inadvertent stings and scrapes is to wear a full suit that covers you from your wrists to your ankles. Wear boots or neoprene booties inside your fins. And wear gloves.
This is the third article in our series on 'Exotic Underwater Nudies', i.e., nudibranchs. We began the series last month with the Spanish Dancer, exceptional for its large size and unique swimming behavior. Next we presented the lovely Gold Lace nudibranch, a species endemic to Hawaii. Today we'll take a look at a very different kind of nudibranch -- different both in form, and in how it makes its living.
The Blue Dragon stores zooxanthellae in its cerata -- those fluffy looking bits that cover its body. In fact, one hypothesis about the Blue Dragon's form posits that the cerata may have evolved in order to provide more surface area for the zooxanthellae to inhabit. More surface area means more space for zooxanthellae, as well as a greater likelihood that they will be exposed to the light they need for photosynthesis.
Earlier this week, for Wordless Wednesday, I posted a photo of a Napoleon Wrasse. Readers commented on the size of the fish, on its shape, and on its prominent eye.
These fish can live for thirty years or so, and they seem to have long memories. When we first began to dive in the Red Sea a few decades ago, dive guides there sometimes would entertain their clients by hand feeding boiled eggs to the Napoleon Wrasses. After awhile, once everyone finally realized that this was not an ecologically sound thing to do, this practice was banned.
Along came a Napoleon. It saw the round white shape cupped in our friend's hand and apparently mistook it for an egg. First the fish swam back and forth excitedly around our friend. Then it nudged him. Annoyed, our friend put out one hand to push the aggressive fish away. At that instant, the Napoleon lunged and snapped the white regulator out of our friend's other hand -- or tried to. The regulator was attached to a hose, of course. When the Napoleon bit, the hose partly detached and it began to froth like crazy from the rapidly escaping compressed air. That scared the fish, which went zooming past us with our friend's glove hanging from its mouth!
