WW #45 - Emperor Angelfish (Pomacanthus imperator) - Red Sea

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WW #33 - Find the little fishy on the coral

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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.

WW #31 - After While, Crocodile

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WW #30 - Crinoid Art

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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.]

WW #27 - Two-bar Anemonefish from the Red Sea

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Wordless Wednesday #25 - A Deep Reef in the Red Sea

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Do Not Disturb: Sleeping Fish

We all need our rest, and so do the fish in the sea. Fish don't sleep exactly like we do. For one thing, they don't have eyelids, so they can't close their eyes. Nevertheless, most fish we know about do take their rest for some part of the day or night, on a fairly regular schedule.

Some fish -- especially pelagics -- hunt at night, and rest during the day. Most reef fish are very busy during the day, so they rest at night. They stop moving about and enter a sleep-like state. While they are resting, they are generally sluggish and not very alert. We try our best not to startle them or disturb their rest during our night dives.

Some fish lie on the bottom to rest, while others hang motionless in the water column. Small fish, in particular, often hide while they are in their somnolent state so that their predators can't find them and eat them. Staying out in the open to rest definitely would give their predators an unfair advantage. In the first photo on this page, a tiny fish called a Pygmy Toby (Canthigaster pygmaea) has snuggled itself amongst corals and sponges to "sleep."

In the second photo, a small fish has chosen to settle into a stand of fire coral to takes its rest. We're not sure what species of fish this is, although the shape suggests that it is some kind of Damselfish.

In addition to hiding, another strategy that many fish use to discourage predation while they rest is to change color. Their color may darken or become mottled during periods of rest, helping them to blend in with their environmental background.

Some species of Parrotfish hide themselves by spinning a slimy cocoon around themselves. The mucous cocoon is secreted from an organ in the head of the Parrotfish. (Sorry, I don't have a photo handy.) It is thought that, in addition to hiding the fish, the cocoon also masks the animals' scent, making it harder for predators to locate them.

Both of the images on this page were captured during night dives in the Red Sea, along the coast of the Sinai Peninsula.

Nephtheid Soft Corals - Pale Pastels

In the past several posts, we've been displaying images of soft corals of the Nephtheidae family. To soothe any damage we may have inflicted on our readers' retinas with yesterday's collection of corals with fiery colors, today we're presenting images of Nephtheid corals in pale pastel colors.

By the way, the species of a Nephtheid soft coral cannot be determined merely by looking at the colors. Corals of a particular species in this family may come in a variety of colors.

All of the corals on this page, as well as on yesterday's post, belong to the genus Dendronephthya, but we're not certain of the species. In fact, I have been told by a marine biologist friend who studies these corals, that the only reliable way (short of DNA analysis) to identify a species of Dendronephthya is by examining certain internal structures, called spicules, with a microscope. In other words, it's next to impossible to reliably determine the species in the field.

For our purposes, we don't mind that we can't be sure of the exact species. When it comes to soft corals, we have been more concerned with collecting images of the different color varieties than with precise species identification. We're content just to know that these are Nephtheids.

At first glance, the more brightly colored varieties certainly are impressive, but we think there is something appealing about the pastels, too. The paler colors suggest a certain fragility, perhaps.

The stalks of almost all of these corals are somewhat translucent. But take a look at the macro image at right: The stalk is nearly transparent! (To see even more detail, you can click on any of the photos on this page to enlarge.)

Some of the corals in this family have greenish coloration, making them resemble plants. A common nickname for those varieties is Broccoli Coral. Other Nephtheid soft corals are sometimes referred to as Carnation Coral. The series of images below may give you an idea of why they acquired this common name.

I took all of the photos on this page while diving in the Red Sea, at reefs along the Sinai Peninsula. I hope you enjoy them.

Nephtheid Soft Corals - Fire in the Night

This past week I began a series about soft corals in the Nephtheidae family, arguably some of the most beautifully colored marine life on the planet. I mentioned that these corals come in a wide variety of colors, and that while they sometimes look like plants, they are in fact colonies of small animals -- coral polyps -- that arrange themselves in bundles on a stalk or stem.

I have a big problem with these corals: There are so many wonderful colors and varieties that I can't stop taking pictures of them!

The colors range from pastel pale, to richly saturated, to just plain knock-your-eyes-out. Today, we'll show you a few that we call "Fire in the Night" -- brilliant reds, oranges and golds.

I took all of the photos on this page during night dives in the Red Sea. These Nephtheid varieties feed mostly at night, so that is when they are plumped up and looking their best, with their feathery tentacles extended like flower petals. Click on any of the photos to enlarge and see more detail.

The first photo on this page is a a soft coral that had attached itself to the underside of a ledge. This bright red and yellow color combination is, to me, the prototypical "Fire in the Night" color. In case you are wondering, that is not an official name; it's just our name for this color variety.

Next is a macro shot of that same coral. You can see that it is the tentacles of the polyps that are bright red. The stalk itself is relatively pale. Those bright yellow bits on the surface of the stalk are sclerites -- hard structures that help it to hold its shape when it is plumped up. They serve a purpose similar to battens in a sail. They also pose a lighting problem to photographers, since they tend to be more reflective than the rest of the coral.

This next variety is a little less fiery than the one above, but is definitely bright and rich. We call this "Golden Glow." This time it's the stalk and sclerites that are golden, while the tentacles on the polyps are almost white.

A similar variety is the one we call "Hot Peach." It has a yellowish stalk, and bright yellow sclerites, but the flower-like polyps are a rosy pink. The combination of the yellows and pinks make it look quite "peachy," we think.

We'll wind up today with a macro shot of the "Hot Peach" color variety. According to my dive log, this image was captured just after dusk. The photo clearly shows that the tentacles were not fully retracted, but not yet fully extended, either.

These corals are not exactly easy to photograph. First of all, they don't need bright sunlight to prosper, so many of them live in deep water, or under ledges and overhangs, or inside cavelets. So, first the photographer has to find them.

Secondly, since these corals are bushy and branchy, they have many planes, and it's difficult to choose a point of focus. Also, since some parts -- especially those calcareous sclerites -- are more reflective than other parts, lighting them evenly can be a challenge.

Shots like the ones on this page were taken at night. Often there is virtually no ambient light underwater at night. So, the photographer (and her helpful dive companion) must locate the subjects to photograph by shining their handheld searchlights this way and that. It helps a lot if the team already has done at least one thorough survey of the area during daylight!

Next, the photographer composes the shot in light provided by a submersible flashlight. Underwater strobes only light a relatively small area -- so the photographer really has to get in close. Meanwhile we have to mind our buoyancy, depth, elapsed time, and our air supply, among other technicalities. But somehow it all comes together, at least some of the time.

Next time we'll show you some paler specimens of Nephtheid soft corals from our photo collection.

Wordless Wednesday #18 - Animal, Mineral or Vegetable?

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Broccoli Coral

This is the second in a series of posts intended to showcase the many colors and shapes of soft corals in the taxonomic family Nephtheidae.

In the first post I mentioned that these corals appear in a countless array of colors. Most grow as tree-like structures having a stem, or stalk, with many branches. Near the ends of the branches are clusters of polyps which open like tiny flowers when they are feeding. When the polyps are closed, they look like little beads.

In fact, when the polyps are retracted, these corals -- especially the greenish colored ones -- resemble broccoli plants, and "Broccoli Coral" is one of the common nicknames given to this type of coral. One look at the photo here, and you'll understand why. (Click on the photo to enlarge.)

Although this kind of coral can resemble broccoli in appearance, it definitely is not a plant. It is a colony of animals -- the coral polyps. The polyps arrange themselves in bundles at the ends of the rubbery stalks. Each polyp has exactly eight short, feathery tentacles. In order to feed, the polyps open and close their little tentacles, grabbing tiny nutrient particles that are suspended in the water.

Many Nephtheid coral colonies contract during daylight hours, making them look a bit shrunken and withered. They expand to feed at night, plumping themselves out and extending all of their little tentacles like bouquets of flowers at the tips of their stalks. For this reason, many of the best photos of these corals are taken during night dives.

I took the photo on this page in the Red Sea, during daylight hours. You can see that the polyps are tightly shut. In tomorrow's "Wordless Wednesday" post, you'll see some macro photos of this same variety of soft coral.

Corals of Many Colors - The Nephtheidae Family

This past week our Wordless Wednesday post was a macro (ultra close-up) photo of a red Nephtheid soft coral. Quite a few people who commented on the photo indicated that they had never seen such a coral, or even imagined there was a coral of that color.

The truth is that corals in the family Nephtheidae are among the most beautiful things a diver will see underwater. They come in a seemingly endless number of color variations. Some of these corals have colors that are are very rich, like that in the image I posted last Wednesday. Others have softer colors, like those in the photo on this page. Nephtheid soft corals also come in assorted pastels, and some are so pale and delicate as to be translucent.

I have hundreds of images of these soft corals, and I must have promised myself dozens of times to stop taking pictures of them. How many photos of soft corals does one person need to take?! But I always end up relenting when I see still another color shade that I haven't photographed before. I can't seem to resist them.

The next several posts will display a sampler of Nephtheid soft corals in their various colors. Most will be macro shots that show not just the colors, but also the structure of this lovely type of marine life. We hope you will enjoy this look at some of our "corals of many colors."

Wordless Wednesday #7 - November 14, 2007

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Fire coral: Another view

After the previous post about fire coral was published, Jerry asked, "Why didn't you include a picture that shows what the whole thing looks like, instead of just some macros? You know, so that divers and snorkelers will know what fire coral looks like before they get too close."

I had to admit, I was remiss in not including such a shot. The photo at right is Jerry's choice to show fire coral as divers and snorkelers are likely to see it. (Click on the photo to enlarge.)

The fire coral species shown here is Millepora dichotoma. Like several other fire corals of the same genus, it tends to have whitish tips while the main structure of the colony has some color. Those of you who have been following this blog for some time could probably guess that this photo was taken in the Red Sea as soon as you saw those bright orange fishies. I've mentioned several times that these little fish, called Scalefin Anthias (Pseudanthias squamipinnis), are ubiquitous in the Red Sea.

We'd also like to note that the background color of this photo is pretty close to The Right Blue!

Fire Coral: Look, but do not touch

When is a coral not a coral? When it is a fire coral.

Fire corals (Family: Milleporidae) look like corals, and that's how they came to be called corals, although some biological characteristics related to their life cycle set them apart distinctly from true corals.

Fire corals are reef builders just like true corals. They secrete a calcareous skeleton. They take on a variety of different shapes ranging from lacy branches (like the example in the first photo on this page), to plate-like structures, to crusts that can cover other things growing on the reef, such as sea fans.

Fire corals and true corals do belong to the same phylum (Cnidaria). A characteristic that all Cnidarians have in common are nematocysts.

Nematocysts are tiny structures on the surface tissue of the organism that are used to capture food, and to defend against predators. Nematocysts actually are very cool structures -- one of nature's engineering marvels. They consist of a fine tube, inside of which is a little coiled thread with microscopic barbs on the end. When something touches the end of the nematocyst it fires the barbed thread into whatever has touched it, just like a little harpoon fired from a harpoon gun.

The second photo on this page is an enlarged 1:1 macro shot of fire coral. The little hair-like structures on the surface (called dactylozooids) are armed with the nematocysts. Touching those little hair-like structures triggers the nematocysts to fire. Click on that photo to see an even larger, more magnified version.

The nematocysts of fire corals carry a toxin that is intended to paralyze the minute bits of plankton that are the fire coral's prey. The toxin also causes pain to predators. Divers who touch or even accidentally brush against fire coral, experience a painful sting that burns like all get out -- thus the name fire coral.

Marine biologists who study these kinds of organisms have discovered something that is useful to know. The nematocysts of fire coral (and their first cousins, the hydroids) are de-activated by acids. Thus, it's a very good idea for divers to include in their kits a small container of vinegar when they visit places where they may possibly encounter hydroids or fire coral. A little squirt of vinegar immediately stops the nematocysts that may still be stuck to the skin from firing.

Conversely, fresh water and soapy solutions actually aggravate the nematocysts. The last thing you want to do if you are stung by hydroids or fire coral is to rinse the skin with fresh water. It actually prompts any remaining nematocysts to fire.

If you are ever stung by hydroids or fire coral, you won't forget it. Usually a welt or rash arises immediately and stays for a week or more, burning again every time you take a shower or bath.

For the record, the fire coral in the first image on this page, is Millepora alcicornis, a Caribbean species. It was photographed in the Cayman Islands. The species in the second photo is Millepora dichotoma, photographed in the Red Sea near Sharm El-Sheikh, Egypt.

Wreck of the Jolanda: Strange cargo

On April 1, 1980 a Cypriot cargo ship called the Jolanda was en route to the Jordanian Red Sea port of Aqaba. As the vessel passed by Ras Mohammed, the cape at the tip of the Sinai peninsula, it encountered very rough seas and ran aground on a reef.

The freighter took on water and sank, coming to a rest on the edge of the reef near a steep dropoff, where it reportedly teetered for several years. Finally, in 1986, a storm took the Jolanda the rest of the way over the ledge, and she sank out of sight into the depths.The Jolanda was carrying containerized cargo, some of which spilled out onto the reef as the vessel broke up. For years, the containers and some of the cargo remained as the only sign of the wreck visible to divers at sport diving depths. We first saw the remains of the Jolanda's cargo in 1989. By that time soft corals already were growing on the broken containers.

For quite awhile, lines and cables attached to one of the more intact containers were used as a mooring for visiting dive boats. This photo was taken in April of 1991, eleven years after the Jolanda sank. On a return visit in late 1995, this particular container was gone, too.
These days not much of the Jolanda's cargo containers remain, but some of the freight that was inside the containers still can be seen littering one section of the reef. No, you're not seeing things. The Jolanda was laden with bathroom fixtures -- toilets, sinks, and bathtubs.
For decades, this cargo has been a source of amusement for divers, and especially for underwater photographers. Nearly everyone who has dived on this reef has taken a souvenir photo of this cargo.

The reef where the Jolanda sank used to be called Turtle Reef. Later it was renamed Jolanda Reef after the famous shipwreck. The name may sound a bit familiar to those who have been reading The Right Blue for awhile. It was mentioned in the story of an exhilarating dive we made in some crazy currents at Ras Mohammed.

Wordless Wednesday #5 - Happy Halloween

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Night shift on the reef

There are nocturnal animals in the sea, just as there are on land. Many marine animals hide all day and only come out at night to hunt, feed, or mate.

The colonial anemone pictured here (Nemanthus annamensis) is one such nocturnal marine animal -- part of the underwater 'night shift' that begins shortly after sunset and lasts until dawn. The only way to see these nocturnal marine creatures is to dive at night.

The anemones in these colonies open as soon as it gets dark. During the night they look like pretty flowers, with their tentacles extended to feed. When morning comes they fold their tentacles inward and each one of the 'flowers' turns into a tightly shut fist. While they are closed during the day they look like nondescript lumps, their nighttime beauty obscured.

The photo was taken during a night dive in the Red Sea, near Sharm el Sheikh, Egypt. If you click on the photo it will enlarge.