Bubble Coral Plus

In the previous article, we introduced our readers to Bubble Coral (Plerogyra sinuosa), a type of stony coral recognizable by the inflated bubble-like vesicles that give rise to its common name. Sometimes other little creatures live in or on the Bubble Coral. We refer to that situation as Bubble Coral Plus.

For Wordless Wednesday, we posted a macro photo of Bubble Coral with a tiny shrimp (Vir phillipinensis) that makes its home among the Bubble Coral's vesicles. The first photo on this page shows another instance of Bubble Coral Plus. This time the Bubble Coral is host to an entirely different critter, the Waminoa flatworm.

The first time we saw Waminoa on Bubble Coral we thought it looked like some kind of algae growing on the surface of the vesicles. We found out only recently that the spots actually were tiny critters. Apparently not too much is known about these flatworms, except that they inhabit some soft corals, as well as the soft parts of the Bubble Coral, and once they are established, the reproduce rather quickly.

This second photo is a 1:1 macro shot. If you click on the photo to enlarge it, you'll be able to see that the Waminoa flatworms look like little pancakes clinging to the surface of the Bubble Coral vesicles. Apparently not a whole lot is known about the Waminoa flatworms, but it is thought that they in turn are host to tiny dinoflagellates -- single cell life forms that produce nutrients through photosynthesis, some of which they share with their host.

I took both of the photos on this page in the Celebes Sea at Bunaken Island. The little island is part of an offshore marine reserve near Manado, on the northern finger of Sulawesi Island in Indonesia. Most of the Bubble Coral in this area has a golden or greenish tinge to it, whereas most of the Bubble Coral we saw in the Red Sea was white, sometimes with a pale bluish tinge. We are not certain if the Bubble Coral in the Celebes Sea is the same species as that in the Red Sea, but it belongs to the same genus, Plerogyra.

Someone who commented on the Wordless Wednesday photo of Bubble Coral mentioned that she had been snorkeling for a long time, and had visited many places, but had never seen Bubble Coral. That was not surprising to us, since it is not usually found at snorkeling depths. We have seen Bubble Coral at many dive sites in the Red Sea, and in various places in the waters around Indonesia and Malaysia, but never at depths of less than about 15 meters (50 feet). Thus, it is unlikely that snorkelers would get to see it.

WW #32 - Bubble Coral with Tiny Shrimp

[Click photo for larger view.]

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Bubble Coral

We have displayed a lot of photographs of reef scenes on The Right Blue. Reefs are formed by corals. The stony corals in the order Scleractinia are the reef-building corals that secrete calcareous skeletons for their polyps, which accumulate over time to become the hard framework of reefs.

We have posted quite a few photos of different kinds of soft corals, ranging from 'broccoli coral' and other Nephtheids to sea fans. Soft corals generally are more colorful and showy, and so they often are more attractive subjects for photography, but without hard corals, there would be no coral reefs. Until now, we haven't really focused much on stony corals, so we thought it was time we introduced some of the more interesting ones to readers of The Right Blue.

Some hard coral colonies form massive lumpy structures that look much like rock. Other stony corals form into fingers, pillars, antler-like branches, or even structures that look like plates. The ridged ones commonly referred to as 'brain coral' belong to the stony coral group, too.

One of the more unusual-looking stony corals we know about is Bubble Coral, an organism in the family Caryophyliidae. The first photo on this page shows a large colony of Bubble Coral on a reef in the Red Sea. If you click on the photo to enlarge it, you will see clusters of what look like bubbles -- thus the common name. Those bubbles, or 'vesicles' as they are properly called, are little balloon-like structures with rubbery skin that inflate during the day.

At left is a macro photo of the vesicles. The species in these photos, Plerogyra sinuosa, is quite common in the Red Sea. Usually it is found on steep slopes or on the vertical walls of underwater cliffs at depths of about 15 meters (50 feet) to about 40 meters (130 feet). I shot the first two photos on this page at Ras Mohammed, a well-known reef at the tip of the Sinai Peninsula.

I took the third photo on this page during a night dive off the coast of Tiran Island, which is situated at the mouth of the Gulf of Aqaba. Although we are not 100% certain, we believe that the organism in the photo is Bubble Coral of the same species as the photos above. Unfortunately, we did not get to return to the same spot in daylight to verify that this was indeed Plerogyra sinuosa.

At night, Bubble Coral looks very different than it does during daylight hours. The Bubble Coral's vesicles deflate, exposing its tentacles and its mouth.

In the photo at right you can see what appear to be the partially deflated vesicles, as well as the little tentacles. The tentacles can sting.

By the way, the vesicles of this species usually are whitish, often with striations of grey or very pale blue. They are translucent, and can look slightly opalescent. We have seen Bubble Coral elsewhere with a golden or greenish tinge. Next time we'll show you some more Bubble Coral, this time from Indonesia. The Bubble Coral we saw there had some 'extras' that led us to think of it as Bubble Coral Plus.

A theme song for The Right Blue

Our blogger friend LavenderBay came up with cool idea the other day, which she wrote about on her blog, Voice of the Turtle. She said:

I was reflecting this morning that I already hear a particular pop song in my head for two of your real-life blogs. So I thought, wouldn’t it be fun to play around on YouTube and discover other theme songs?

I had three criteria: I really like the song; it has to come from the country where the blogger lives; and it can be located on YouTube.

In her article, A Musical Interlude, she then listed a dozen blogs from her blogroll, chose a song that she associates with each blog's content, and posted links to the YouTube video for each of those. We think this is a clever and appealing concept. Go and have a look, and you'll see what we mean.

For The Right Blue, she chose John Denver's song "Calypso," about Jacques Cousteau's ship and undersea adventures. We are truly touched and honored by her choice, and we thank her. Here's the music video:



(If the video does not play or display properly above, click here to view it on YouTube.)

WW #31 - After While, Crocodile

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What Brutus the Great Barracuda Saw

In the previous post I wrote about a Great Barracuda named Brutus who liked to follow Jerry around the reef at Puako. If you read that post, you'll recall that after a few experiments, we concluded that the big fish actually was attracted to the yellow sleeves on Jerry's wetsuit, probably because the color stood out so well against the background, compared to the black and dark blue suits the other divers in our group were wearing.

Today I was looking through some recently scanned photos, and by chance I came across this nice shot of Jerry with a school of Horse-eye Jacks. I took it with natural light -- no flash -- at Providenciales in the Turks and Caicos Islands. Looking first at the thumbnail, I thought, "This looks like a Right Blue photo." But when I enlarged it on my monitor, I knew instantly: "THIS is what Brutus saw!"

See what I mean? (Insert 'big grin' emoticon, heh heh.)

[Click on the photo to enlarge]

Remembering Brutus, the Great Barracuda

You would think that after doing thousands of dives at hundreds of dive sites around the world, we would not remember encounters with individual fish. Who knows how many different fish we have seen in our long years of diving? Yet there are a few individuals among the masses that do stand out in our memory. One of those was a big silvery fish that hung out near our home reef at Puako, Hawaii for the better part of a year.

That big silvery fish was a Great Barracuda (Sphyraena barracuda), just like the one in the photo at right. I photographed that one in the Caribbean, but we have seen this species all over the world, and have had many close encounters with them. Most of our encounters with barracuda were unremarkable, until we crossed paths with the one we came to call Brutus.

Brutus the Great Barracuda was 'great' in more ways than one. He was great in size: we figured he was about five feet long and probably weighed around 70 pounds. He also was a great companion: if he spotted us from a distance he'd hurry to us, and then follow us around for most of our dive.

Seeing a big barracuda like Brutus underwater can make the hair on the back of a diver's neck stand up and prickle, but Brutus never harmed us, nor did he ever give any sign that he wanted to do anything more than watch what we were doing. In fact, he could be downright nosy.

Usually Brutus followed us at a respectful distance of, say, 20 to 30 feet. But there were times when we'd stop to look closely at some tiny little creature, and that distance would close until we'd have Brutus looking right over our shoulders. I don't know why he did that. Maybe he thought we might have found something good to eat, and he didn't want to miss it. What I do know is that sometimes we'd turn our heads, and there would be this big barracuda face with the gnarly-toothed grin right there!

When Brutus first started to follow us around, we thought maybe we were imagining it. We thought maybe the big fish just happened to be going where we were going, and was not really following us at all. So, along with our friend Dan, we cooked up an experiment: We agreed ahead of time that if we saw Brutus and he started to follow us, we would reverse direction, swim past him, and see if he then turned around and stayed behind us. He did. After a few more rounds of this we concluded that he really was following us intentionally, and not by chance.

Then we noticed that Brutus seemed to prefer Jerry to Dan and me. When the three of us were diving together, it was our habit to swim more or less parallel to one another, but about 15 or 20 feet apart. We noticed that when we fanned out like that, Brutus would watch all of us, but seemed to follow Jerry more closely. So, we planned another experiment. On one dive, Jerry would be positioned in the middle, with Dan and me at either side. On another dive Jerry would take an end position, and either Dan or I would take the middle spot. Sure enough, regardless of which position in the line-up Jerry took, Brutus would be right behind him.

What was it about Jerry that attracted this big barracuda? The probable answer came one day when I stopped to look at something, while Jerry and Dan swam ahead. When I looked up to see where they were, I spotted Jerry right away. He was wearing a wetsuit that had bright yellow sleeves, and had on yellow fins, too. The yellow was very visible, even from a distance. I couldn't see Dan until I got closer. Dan's suit was all black, just like mine. It was one of those 'lightbulb' moments. "Aha!" I thought. "That's it!" It probably was the yellow in Jerry's dive attire that attracted Brutus.

Barracuda are believed to be attracted to shiny things, probably because much of their diet consists of little silvery fishies. It occurred to me that, while Jerry's fins and wetsuit were not shiny, the yellow color definitely stood out in contrast to the background. You know what's coming, I'll bet. One more experiment.

The next time we went diving, Jerry and Dan swapped suits. Jerry wore all black, and Dan now wore the suit with the bright yellow sleeves. Along came Brutus. We fanned out across the reef, with Dan in the middle, dressed in Jerry's suit. Just as we had hypothesized, Brutus now followed behind Dan. When they switched positions, Brutus still followed Dan. We concluded that it was indeed the yellow in the suit that had attracted the barracuda. After that, we referred to that suit as Barracuda Bait!

So, if you're diving in waters where there are Great Barracuda about, and you don't want to attract their attention, do not wear a high-contrast outfit underwater. Wear a suit that blends, not one that stands out. Don't be barracuda bait.

WW #30 - Crinoid Art

[Click photo for larger view.]

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Crinoids - Also Known As Feather Stars

In the previous post, about our final dives on the wreck of the Zenobia, I mentioned that we saw crinoids inside the shipwreck. As I wrote that, I realized that many readers, and especially non-divers, probably had never seen or even heard of crinoids. They're strange creatures, and I was hard pressed to describe them for that story, so I thought it would be a good idea to show readers of The Right Blue what a crinoid looks like.

The photos on this page show a crinoid known as Klunzinger's Feather Star (Lamprometra klunzingeri), a species found commonly in the Red Sea. This is not the species we saw inside the Zenobia, but these photos should work well to illustrate what a crinoid is like.

Crinoids belong to the same phylum (Echinodermata) as sea stars and urchins. The phylum name means "spiny skinned" and most members of the phylum do have some kind of spiny structures on their outer coverings.

The crinoids have feathery arms, which are jointed. They can (and do) bend every which way. The arms have rows of protrusions, called pinnules, which run the length of the arm, making them resemble feathers. The crinoids catch their food by extending their arms like a fan. Bits of plankton are caught on the pinnules.

These creatures also have a set of appendages, called cirri, that serve as feet. They can move along on the cirri a little bit, but they also use their feathery arms to propel themselves. Sometimes they bend their arms down in a sort of arc, and use them like extra legs to skitter across sand or other flat surfaces. They use their cirri to hold on tightly to whatever they decide to perch upon.

There are teeny tiny hooks on their ends of the cirri, which help them to grab onto their perch. We have seen these actually puncture a sponge enough to leave a scar. I should also add that, on occasion, we have attempted to move a crinoid from one location to another. It's fairly easy to put a gloved finger next to a crinoid's little feet, and nudge it to perch there. The trouble comes in getting the crinoid to release its hold on that gloved finger again!

Crinoids are nocturnal creatures. They fold themselves up into a ball and hide in crevices in the reef during daylight hours. They usually emerge from their hiding places at dusk, and situate themselves on a favorite perch -- on coral, a large sponge, a sea fan -- wherever they can anchor themselves well. Then they unfold their feathery arms and feed all night, returning again to their hiding places at first light.

Crinoids are sensitive to light. When they are exposed to a bright light, they immediately begin to fold in their arms. For this reason, it is sometimes difficult to photograph them in their full glory, with all their arms completely outstretched. Crinoids are fairly plentiful on many reefs, so they are relatively easy to find during night dives. However what often happens is, we shine our lights around and spot a lovely crinoid, but as soon as it senses the light beam it begins to curl up. So, we switch off our lights and wait. Eventually the crinoid will unfold again, but then the photographer is lucky to get more than one or two shots before the light from the camera's strobe prompts the crinoid to fold into itself again. It takes patience to photograph crinoids.

The two photographs on this page were shot in quick succession. In the first photo, the crinoid's arms are fully extended. (Take note of its little cirri, hanging onto the coral it has chosen as a perch.) In the second photograph, the crinoid already is reacting to the light emitted by the flash during the first shot, so it's beginning to curl up. I photographed this crinoid during a night dive in the Red Sea, off the coast of Egypt's Sinai Peninsula. [Click on the photos to enlarge.]

Final Dives on the Wreck of the Zenobia

This is the final article in a series about our seven dives on the wreck of the Zenobia, a large ship that sank off the coast of Cyprus in 1980. If you missed the earlier episodes, we invite you to scroll down to the bottom of this article for links to the whole series.

In the most recent episode, we talked about our first dive inside the sunken ship. For that dive, we entered the Zenobia's upper parking deck through a doorway near the bow end of the ship, swam through, and exited through a larger opening closer to the stern. For successive dives, we took the opposite route, entering the parking deck through the larger opening and exiting through the doorway situated underneath the ship's bridge, near the bow.

The first dive inside the ship was all about getting a feel for the vast interior space that had been the big ferry's upper parking deck. Now that we were more oriented, we could concentrate on what there was to see of the Zenobia's cargo, and the creatures that had taken up residence inside the sunken ship.

I mentioned earlier that the Zenobia was carrying more than 100 fully loaded lorries (trailer trucks). Those trucks, which had been lined up in the parking deck when the ship was still on the surface, now lay in a jumbled pile against the port wall of the parking deck, having tumbled there as the ship sank and settled on the sandy bottom on its port side. Many of the trailers had broken up and released their pallets of cargo to scatter about. We saw shoes, clothing, machinery, and cans of house paint that had been destined for distant ports, but never made it.

We looked all around inside the big ship, shining our lights here and there as we went along. In one of those sweeps, we saw what looked like a pile of bones. As far as we knew, no one had died when the Zenobia sank, so we were very surprised to see bones -- big bones -- piled in disarray near the remains of a half-disintegrated truck body.

Looking more closely, we saw what looked like thigh bones and ribs -- BIG ribs. It was a grisly looking sight and we were taken aback at first, but on closer inspection it became clear that we were looking at animal bones. The bones were all that remained of the cargo of a refrigerated truck that had been on board the Zenobia. The truck had apparently been carrying sides of beef and other large pieces of meat. Over time the bones had been picked clean by fish and crabs, I guess. The truck in which they were being transported had decayed and broken open. In sum, it was a rather distasteful sight, and we didn't linger.

In addition to the lorries and what remained of their cargo, we did see a lot of other things inside the parking deck, including an amazing assortment of living creatures. We saw several kinds of crabs, and two species of small nudibranchs (snails without shells). We saw many crinoids -- also known as feather stars -- a class of creatures that are in the same phylum as sea stars (starfish), but with arms that resemble feathers and a separate set of little feet that they use for locomotion, and also for hanging on to wherever they are perched. The crinoids inside the Zenobia were very delicate and flimsy looking, compared to most we had seen elsewhere.

We saw quite a few fish, of course, darting in and out of the debris inside the Zenobia's parking garage. They were mostly small fish, like little wrasses and cardinalfish, and two small groupers. The photo at left shows the now-horizontal doorway that was our entrance for our first dive into the parking deck, and our exit for the final two dives. It looked a bit smaller when we were further inside the wreck, but it made a nice picture frame for fish that were busily going about their business outside the wreck. At one point we looked toward that door and saw framed there a small school of silvery jacks zooming past in a parade, a lovely sight we'll never forget.

While most of the fish we saw inside the wreck were small, we did see one large grouper. He was hiding in a nook a few meters inside of the door where we would exit. We disturbed him inadvertently, and he shot out between us and hurried through the door, away from us. Ten minutes or so later when we emerged from the wreck, there was the big grouper, hanging out near an algae-covered ladder on the exterior of the ship, not far from the doorway. As soon as we were completely out of the parking garage into the open again, the grouper hurried back inside, looking very annoyed. I could have sworn I heard him 'harumph' as he passed by us, probably calling us names under his fishy breath for having disturbed him in the first place.

On our next to last dive on the Zenobia, we saved a little time to swim through the ship's bridge. We also had a look inside what had been the ship's restaurant, where the drivers of all those lorries took their meals during the voyage. We saw three more small groupers in there, too.

One of our favorite finds on the Zenobia was a good-sized Mediterranean Moray (Muraena helena) that had taken up residence in a drain near one of the Zenobia's lifeboat stations. Ian, our guide, told us that eel had been living there for quite some time, and could be found in that spot reliably, just about every day. Click here to see a photo of the Mediterranean Moray that made its home on the Zenobia.

We felt fortunate that we had a whole week to spend on that trip, so that we could take our time exploring the Zenobia on those seven dives. This was not the first wreck we had dived on, nor was it the last, but to this day, we have never dived on a larger shipwreck. Diving on the Zenobia was a truly memorable experience.

We'll end our tale with a photo of the divers in our party ascending from the wreck for the last time, making their final decompression stop before climbing into Ian's boat to go back to the dock in Larnaca. Ian McMurray, who pioneered diving on the wreck of the Zenobia, and who was our guide for our dives there, is still taking divers to see this huge underwater wonder. If you are interested, visit the Octopus Diving Centre in Larnaca, Cyprus. Tell Ian that you read about the Zenobia on The Right Blue, and give him our regards.

Here are the links to all of the articles in this series about diving on the wreck of the Zenobia, near Larnaca Cyprus:

• Diving the Wreck of the Zenobia - Introduction


• The Wreck of the Zenobia - A Brief History


• First Dives on the Wreck of the Zenobia


• Bottom Time on the Wreck of the Zenobia


• Diving Inside the Zenobia's Parking Deck


• Final Dives on the Wreck of the Zenobia

More photos from the Zenobia:

• Taking Pictures on the Zenobia


• Diving on the Wreck of the Zenobia


• Mediterranean Moray