Colony of Long Red Sea Whips - Indonesia

What: A colony of Long Red Sea Whips (Ellisella sp.), a type of soft coral.

Where: I took this photo in the Celebes Sea at Bunaken Island, Indonesia.

[Click photo to enlarge.]

My previous Wordless Wednesday posts.

The Blue Dragon, a Solar-Powered Nudibranch

by B. N. Sullivan

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.

Meet the Blue Dragon (Pteraeolidia ianthina). This is one of a handful of nudibranch species that is, in effect, solar powered. I know what you're thinking: A solar-powered sea slug? How is that possible?

It happens in a round-about way. The Blue Dragon is carnivorous. It eats hydroids -- stinging organisms that are related to corals. The hydroids are colonized by zooxanthellae -- microscopic plants. As plants large and small are known to do, the zooxanthellae convert energy from sunlight into sugars through the process of photosynthesis.

So, the Blue Dragon eats hydroids, which contain zooxanthellae in their tissues. The Blue Dragon is one of several nudibranch species that has evolved a method of extracting the zooxanthellae from the hydroids it eats and storing them in its own body. Once in place in the nudie's tissues, the zooxanthellae continue to produce sugars via photosynthesis, thus nourishing the creature that has now become their new host. In this way, the Blue Dragon qualifies as a solar powered nudibranch.

Zooxanthellae are found in the tissues of many marine animals, including corals. In fact, it is the presence of zooxanthellae that give corals their colors. The same is true for the Blue Dragon nudibranch. The coloration of this species varies, partly due to the concentration of zooxanthellae that a given individual carries in its tissues. Juveniles of this species are a nearly transparent white. Only as they mature and accumulate zooxanthellae in their tissues do they take on their characteristic color.

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.

Speaking of sunlight, as you might expect, the Blue Dragon nudibranch works the day shift on the reef. It needs to be exposed sunlight so that its zooxanthellae can produce nutrients. Not only is this creature seen most frequently during daylight hours, it also tends to dwell at shallower depths than some other nudibranchs. Naturally, there is more sunlight available at shallower depths than in deeper water.

About the photos on this page: In the photo at the top of the page, you can see how the cerrata are arrayed along the entire length of the Blue Dragon. Zooxanthellae are stored in the cerata. The bottom photo is a 1:1 macro of the head of a Pteraeolidia ianthina. The feathery looking bits protruding upward from its head are its rhinophores, the organs that sense 'smells' in the water. The animal uses its rhinophores to locate food, much like a mammal on land would use its nose. The striped appendages facing forward are oral tentacles, which act like 'feelers' so that the nudie can pinpoint where the food is, by touch.

Each photo shows a different individual. The photo at the top was taken at Siapadan Island, off the coast of Borneo. The bottom photo was taken near Manado, Sulawesi Island, Indonesia.

Napoleon Wrasse in the Abstract

What: The first two images are abstract macro shots of the scales and a fin of a
Napoleon Wrasse (Cheilinus undulatus).

The third photo is for context, so that you can see the patterns as they appear on the fish.

Click on any of the photos to enlarge.

For more about the Napoleon Wrasse, click here.

Fish Tales: Encounters with the Napoleon Wrasse

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.