The Kanton Campaign for Kids

Hello dear readers, and happy holidays!

Emily Mead, a local high school student, is sponsoring a campaign for the children on Kanton Island. When the expedition team visited the Kanton Island school, the students gave us a list of items that they need. In the spirit of the holiday season, I encourage you to donate!

Items (or funds for items) can be dropped off or mailed to the New England Aquarium, attn: Regen Jamieson, Conservation Department; 1 Central Wharf, Boston, MA 02110.

Photos of the Kanton Island school and kids (photos: L. Madin)

Emily's summary and list are as follows:

Kanton is the only inhabited island out of the eight that make up the Phoenix Islands. The Phoenix Islands are located in the country of Kiribati. Kiribati is in between Australia and California. Kiribati includes 33 islands in three different island groups, 277 square miles of land, in 2 million square miles of the Pacific Ocean. The Phoenix Islands include 11 square miles of land. The Phoenix Islands Protected Area (PIPA), including its archipelago and surrounding waters, is 157,626 square miles, making it the largest protected area in the world and about the size of California. Kanton is included in this area, and needs your help. The teachers of the school on Kanton requested some materials, to educate their students more and teach them about the oceans surrounding them. So, by helping them in any way makes a big impact. We greatly appreciate your generosity, and happy holidays!

Materials Requested:


Pencils & Pens


Poems & Songs

Posters of the internal and external parts of fish

Posters of types of fish and reefs

Wall clock


Thank you!

Items (or funds for items) can be dropped off or mailed to the New England Aquarium, attn: Regen Jamieson, Conservation Department; 1 Central Wharf, Boston, MA 02110.


And the experience .....priceless.

The last of the Phoenix Islands "Greatest Hits" highlights.#10: Future PIPA ExpeditionsOkay, I admit it. I have been stalling on this last post. The truth: I have no idea how to end this blog. How do you put a neat, satisfactory end on something so wild? Anything I write will be anticlimactic. With this in mind, let me simply offer you some stats to let you know how where things stand as of this very moment:

...15 Expedition members, now spread all over the globe
...15 amazing NAI'A crew members (based in Fiji) 
...100+ bags of luggage transported to and fro
...400+ SCUBA dives completed on the 2009 expedition
...4 blue water dives
...3 ROV excursions
...11 days on-site in PIPA
...11+ days in transit (5 in very rough seas)
...500+ species of fish documented
...200+ invertebrate species documented
...3+ scientific publications in progress
...5000+ photos of PIPA (see previous posts for highlights)
...65 blog posts
...12,000+ blog readers (Thank you!)
..........408,250 km2 of protected ocean
(PIPA remains on of the world's largest MPA)

And the experience ..... priceless.

Thank you all so much for reading and journeying with us. Special thank you to Jeff Ives (the New England Aquarium blog guru) for all of his support. Special thank you to all of the fellow bloggers who posted, students who participated, and readers who commented. To those silent readers - thank you - we hope you had as much fun reading as we did writing. It was a blast. I still don't know how to end this blog (mea culpa), so I'll leave you with some comforting thoughts:

1. The next PIPA expedition is slated for 2011. Stay tuned, and we'll keep updating this blog to let you know exactly when.

2. We'll post 2009-PIPA related press, publications, lectures, and outreach efforts here on this blog. These will include a book, a National Geographic article, a movie, scientific publications, and press.

3. This blog will not disappear (it will remain on the Aquarium website), so you can re-visit the 2009 expedition at any time. With 65 posts to go through, it will certainly keep you busy to go back to the beginning! Plus, the New England Aquarium is never idle - there are always amazing adventures all over the globe (including at 1 Central Wharf, Boston!), so check out the other blogs to see what's going on.

So, thank you! And don't forget to live blue.

Happy holidays,



The Lorax and the Laroc

The Phoenix Islands "Greatest Hits" highlights continue...

#9: PIPA coral forestsIf you've never read The Lorax (Dr. Seuss), you're missing out. It's a brilliant book about Truffula Tree Forests, which support a high diversity of magical, mystical creatures like Bar-ba-loots and Swomee Swans and Humming Fish. In this story, the forest gets slowly cut down by the Once-ler in order to knit thneeds (that everyone needs!). As the Once-ler systematically destroys the forest, the fantastical inhabitants suffer. They face food shortages and disease and suffer from smoke pollution (from the Thneed factory, of course). The Lorax is one of the strange forest dwellers, and the self-proclaimed spokesperson for the trees. The Lorax tries to warn the Once-ler that at the rate the forest is being destroyed, it will no longer support the thriving thneed business (let alone the diverse and complex forest community). "I am the Lorax, I speak for the trees, which you seem to be chopping as fast as you please...".

Photo: J. Stringer

Enough rambling. What does The Lorax have to do with corals? More than you think! Trees create the forest, and the same goes for corals. No trees, no forest, no fantastical forest creatures; no corals, no reefs, no spectacular reef creatures. And by the way, The Laroc is just "Coral" backwards. :-) Check out the photo above this paragraph, and below (top) of the coral with fish hiding among the branches and curls. From the fish's perspective, the coral is certainly a forest! Similarly, look at the beautiful archway in the photo below (bottom). Though the arch is topped with a few live corals on the top, the arch is mostly composed of dead coral skeletons that are *still* providing reef structure - yup, it was all built by corals.

Photo: R. Rotjan

Photo: J. Stringer

Corals grow very slowly. Take the brownish Halomitra coral with purple edges. The edges are the growing tips, not yet populated with symbionts. As the symbionts colonize the areas of new growth, the coral will turn brown (purple is a pigment produced by the host; brown/green is a pigment produced by the symbiont). For more information on host-symbiont coral relationships, check out the chapter in the Aquarium's Blue Impact multimedia tour called "color changing corals."

Slowly, corals grow into vast underwater forests, like the Hydnophora coral forest below. These forests provide shelter for many fishes and reef invertebrates. If these forests get destroyed, there is no Laroc (Lorax) to speak for them. Luckily in the case of the Phoenix Islands, the reefs are well on their way to recovery following the severe 2002 bleaching event. But that's not true everywhere, and corals need your help to stop the pollution, overfishing, disease, and myriad other stressors that threaten their very existence.

A living coral forest: Photo: J. Stringer

Amazingly enough, we don't need to go all the way to the Phoenix Islands to see corals. Now that we're home from the expedition, I'm once again thinking about my backyard coral reefs. Here's a glimpse of a coral species that grows right here in New England - the Great Northern Star Coral. It doesn't get as big as the tropical corals, and it doesn't create vast forests, but it is our local coral reef, and is certainly worthy of mention. :-) Plus, WHOI scientists are using it as a model system to examine the effects of climate change.

So with that, whether they be tropical or temperate corals, I leave you with these wise words from Dr. Seuss:

Plant a new Truffula. Treat it with care.
Give it clean water. And feed it fresh air.
Grow a forest. Protect it from axes that hack.
Then the Lorax and all of his friends may come back."


Phoenix Islands on IMAX!

Although we still have 2 more stops on our "greatest hits" site, I am going to take a blogger's liberty of another sidetrack to acknowledge the amazing outpouring of support and interest in the Phoenix Islands. Thanks to all who came out on Monday night for the lecture to come meet the expedition members (Greg, Alan, Les, and Randi). The talk was upgraded to the IMAX theatre, which was great fun--50-foot PowerPoint slides!

Special thanks to the students of Souhegan High School in Amherst, New Hampshire for coming; see their earlier posts to the blog here and here.

Les and Greg (left) and Alan and Randi (right) meet with students from Souhegan High School, with teacher Julianne Mueller-Northcott (center; in green). Thanks for coming! (photo: J. Wolman).

We've been back for about three weeks now, and we all miss the Phoenix Islands. Luckily, we can go downstairs to our exhibits to see live corals and giant clams and fishes to remind ourselves of the amazing adventures on the equatorial Pacific.

Pacific Reef Community tank at the New England Aquarium (photo: R. Rotjan)

Stay tuned for the remainder of the greatest hits...



Want to hear more about the Phoenix Islands? Want to meet some of the expedition members in person? Want to meet some of the students who corresponded with the team on this very blog? Want to see new (never before seen!) photos?

Join us THIS COMING MONDAY, November 2, at 7pm. The lecture is free; and free snacks will be provided as well!

Please register (free!) using this link - seats are limited!

Phoenix Islands Residents (photos: J. Stringer)

Rising From the Ashes: The Phoenix Islands Protected Area
These days it is impossible to find an ecosystem that is untouched by man. Human effects are felt from the polar ice caps to the deep sea, and coral reefs are far from the exception. The major stressors on most reefs--sewage inputs, overfishing, point-source pollution and extensive tourism--are local. However, a few remote places still exist where reefs are not affected by these local stressors; humans only affect these reefs on a global level. The Phoenix Islands are among these treasures. Their remote location, coupled with their intensive regulations and protection, create a unique opportunity for scientists to study a reef free from local impact.

New England Aquarium researchers recently participated in a rare expedition to the Phoenix Islands. In this lecture they will share scientific findings as well as anecdotes from this remarkable adventure.

Stuart, David, Les, and Randi underwater, measuring reef creatures like the clowfish and anemones featured here (photos: J. Stringer)



One Fish, Two Fish, Red Fish, Blue Fish

The Phoenix Islands "Greatest Hits" highlights continue with this guest post by Stuart Sandin.

#8: Measuring the diversity, abundance, and biomass of PIPA fishes

Although corals and some algae form the backbone of a coral reef, it is the fish that give reefs their personality (at least from the perspective of a 'fish guy'). Notice, for example, that movie writers and animators did not have us finding Porites corals, but instead we focused on the reef fish Nemo and his friend Dori. Without fish, a reef would be essentially static, with limited color and even more limited movement.

(Photos: R. Rotjan)

We fish guys make a living out of looking for fish, counting how many are around, and trying to figure out what they do. This all begins with advice from Dr. Seuss, "One fish, two fish, red fish, blue fish." During our time in the Phoenix Islands, Les, Tuake, and I tried to gain some ecological perspective regarding the fish from each of the islands. In set areas, we counted every fish swimming around, identifying the species and estimating each fish's size. From this we can estimate some fundamental properties of the fish assemblage -- how many fish are around, how much do they all weigh (which is important because fish vary dramatically in size), and what are the ecological roles that these animals are filling?

(Photos: R. Rotjan)
Now what did we find? Well, we were able to confirm the long-pondered concept -- if you don't fish in an area, you get more fish. The reefs of the Phoenix Islands have no fishing activity, so it is not surprising that we find more fish there than in more heavily fished areas like Fiji, Hawaii, or any other inhabited island. But what is surprising is the sheer bounty of fish that were present on the reefs. It seems that during every dive we would come across a large school of some species; sometimes we saw dozens of giant trevally, or hundreds of parrotfish, or thousands of convict surgeonfish. Add up all of these fish and you have a particularly large assemblage of animal mass. The best insights into this is perhaps completed by comparing the fish assemblages from the Phoenix islands to more commonly visited areas. Let's use the metric of total fish biomass (in other words, imagine that you took every fish out of a section of reef and weighed them...this is our metric of choice when summarizing multi-specific fish assemblages). Our surveys of the Phoenix islands revealed that there were about 250 grams per meter squared of reef, or about a half pound of fish in the area of the hood of a car. In contrast, the reefs of the main Hawaiian islands, Fiji, and Jamaica have about 65, 30, and 20 grams per meter squared, respectively. The reefs that most people visit during vacation are a shadow of their historic potential.

(Photos: R. Rotjan)

But the reef fish of the Phoenix islands were not wholly pristine and devoid of the scars of human activities. On a number of the islands we did not see many reef sharks, and when we did find them the animals were small and young. Although fishing is currently outlawed from all reefs within PIPA, this has only been true for the past few years. Within the past 10 years there has been some fishing activity on the reefs, particularly targeting the sharks for their fins. Catering to a lucrative market for shark fins (used in shark fin soup), foreign fishing vessels find it to be profitable to legally (and sometimes illegally) to visit even the most remote reef areas to harvest sharks. The regulations of PIPA prohibit any future shark finning from the reefs of the Phoenix islands, and the good number of juvenile reef sharks that we saw during this trip suggests that a recovery of shark populations is possible. But in order to realize this regrowth of shark populations, we have to assure compliance with the regulations. Multi-national efforts to improve surveillance of the remote and protected areas of the Pacific (under the jurisdictions of Kiribati as well as French Polynesia, the United States, and other nations) are beginning and will be essential to protect the splendor of these last remaining gems in sea.

The theme of 'Phoenix rising' has been common during this trip -- we saw evidence of the corals recovering from a massive bleaching event, we saw bird populations soaring following removal of introduced rats, and we also see evidence that even the insulted shark populations can recover to full glory. I am proud to have been a part of such a proactive team of conservationists, politicians, and scientists focused on protecting the Phoenix islands. Only due to this type of effort can I hope that we will protect, and perhaps even improve, vast regions of the ocean for our children and their children to marvel at into the future.



The Snappers in our Grouper

The Phoenix Islands "Greatest Hits" highlights continue...

#7: Photography and videography on a scientific expedition

We were fortunate to have several excellent professional and amateur photographers and videographers with us on this trip. You've heard directly from Brian Skerry, the award-winning National Geographic Magazine (NGM) photographer with us (see Brian's earlier posts here). But we also had Jeff Wildermuth with us, assisting Brian and making professional videos for the New England Aquarium and Conservation International.

Jeff Wildermuth, in action (Photo: R. Rotjan)

Jim Stringer is an excellent amateur photographer who has provided many of the photos posted on this site. In addition, Rob Barell and Sam Campbell (NAI'A) shot terrific, high-def video footage of the science-in-action, the reef denizens, and anything else in sight. Craig Cook was not only our MD; he is also an accomplished photographer and helped to capture the essence of our trip, as well as helped Les Kaufman take some scientific footage of coral fluorescence. It's quite likely that hundreds of thousands of photos were taken--I'm not a real photographer (neither pro nor high quality amateur), but I took over 3,000 shots! Add that to the impressive skills of Kate, Larry, Les, David, Greg, Stuart, Tuake, Tukabu, and Alan... and you get the idea. This trip was well documented by all of these photographers (snappers) on our trip (in our group-er). My apologies for the bad puns.

Our snappers, in action - L. Madin, S. Campbell, J. Stringer. (Photos: R. Rotjan)

So, speaking of snapper, what was the most photographed fish? My guess is the charismatic and in-your-face red snapper (Lutjanus bohar); they were everywhere! As for coral, my money is on Porites lobata (a lovely mounding coral present at most sites). David Obura might be the most photographed human; he is especially photogenic with a clipboard and transect tape in hand. Fairy terns might be the most photographed bird. But in truth - I have no idea. Even 2 weeks later, we're still compiling our photographs and sharing files. However, many of our images will be published in Aquarium publications, and shown on November 2 (lecture details here), so keep your eyes open. :-) You never know when you might recognize a Phoenix Islands photograph premiered here on this blog.

Snapper with snappers! (Photo: R. Rotjan)

Before this trip, I had no idea what it was like for Brian and Jeff, our professionals, to photograph a story in the field. I'll re-post some comments of Brian's here, since he says it best:

"Photographically, the challenges have been substantial. Even when all is perfect on these central pacific reefs, making great images can be difficult because fish are skittish and hard to get near. The nature of being on an expedition means we also move continually in order to collect scientific data, so each dive is in a new location. Without the chance to dive the same sites repeatedly and gain knowledge about subtle nuances, I must simply spend as much time in the water as possible and hope to find something especially interesting happening."

Brian and Jeff with gear on the boat; Brian contemplating unpacking the photo gear (Photos: R. Rotjan)

"For this assignment, I have 11 days to photograph underwater, quite a bit less than the 10-12 weeks I typically have for an NGM assignment. Still, I hope that the handful of key images I've produced so far and others I hope to make in the few days remaining will speak to the important story and illustrate the issues we are experiencing here I the central Pacific Ocean."
Brian is being modest--he may have only a handful of images that meet his extremely high standards, but we were all wowed at our first glimpse of his photos. He captures movement, texture, and energy that really demonstrates the wildness of the Phoenix Islands Protected Area.

It was terrifying having the pro's photograph us, however! During our "Phoenix Islands Firsts" post, Tuake described what it felt like to be under the lights:

"I was a bit nervous to be photographed by the National Geographic People! I was finding it hard to breathe on my tank when Brian was taking pictures of me. Normally, I like to be underwater for the fun of diving. I felt relieved when Brian was telling me that he was done with me. I hoped that I had done what I was supposed to do as part of my Phoenix Islands mission. I count myself fortunate to be attached and learning from highly academic scientists who are on this marine expedition. This was indeed a first for me--to be photographed for a magazine story."

Multiple snappers - count 'em, three! (Photo: R. Rotjan)

As for me, I managed to avoid the camera most of the time and be a "snapper" in my own right.... taking photos for science and pleasure with no remorse (thank goodness for digital photography and large memory cards!). But if this post has you hoping for more information on the *real* snappers and groupers of the trip - and yes, I do mean the fish - stay tuned! Stuart and Les will be guest-blogging soon on the fishes hits of the trip. :-)




Put the Lime in the Coconut

The Phoenix Islands "Greatest Hits" highlights continue...

#6: Medical objectives and triumphs of the 2009 PIPA expedition

Some of the most incredible highlights from the trip were the things that never happened. These things are of huge concern when headed 5.5 days away from anywhere, and when engaging in high-risk activities such as repeatedly diving in shark-filled waters with sharp corals at every turn. Of course, there are always the other regular afflictions--sun poisoning, broken bones, infected wounds, parasites, disease and who knows what else. So, you can see that it is quite worth mentioning that no major medical maladies occurred on our expedition. Hoorah!

Dr. Craig Cook on SCUBA with camera in hand and no sharp coral in sight (Photo: R. Rotjan)

Despite our good fortunes, we weren't willing to risk our lives on luck alone. Instead, we placed our lives into the care of the NAI'A, and into the very capable and experienced hands of Dr. Craig Cook, who was our expedition medical doctor. Craig is no stranger to practicing medicine in high-risk, remote locations. He is the Medical Editor for Sport Diver Magazine and a referral physician for Divers Alert Network. With a background in Anesthesiology, Dr. Cook has been a consultant to the National Oceanographic Atmospheric Administration (NOAA), and is also a scuba instructor and has been actively diving for 40 years. It is with his guidance and wisdom that we hauled a Hyperlite Hyperbaric Chamber with us all the way to middle of nowhere.

Dr. Craig Cook (black shirt) demonstrating the hyperbaric chamber to expedition members (photos: R. Rotjan)

What exactly is a hyperbaric chamber? It's used to treat decompression sickness, (aka "the bends"), which can occur when diving. Basically, divers are at pressure (every 30 feet of depth is equivalent to approximately 1 atmosphere of pressure). The air we breathe is a mix of gasses, including oxygen (~21%) and nitrogen (~78%). At depth, air is compressed (more or less depending on the diving depth), but "the bends" occurs upon depressurization. As divers return to the surface, gas expands as the pressure decreases, and air (basically a mix of dissolved gasses) can form bubbles. Bubbles are usually small and eventually dissipate, but sometimes a bubble forms that is too large, or unfortunately located, and can cause illness ranging from mild to extreme severity. Its effects may vary from joint pain and rash to paralysis and death. To treat the formation of bubbles, doctors use a hyperbaric chamber to recompress a patient (simulate diving depths) while on oxygen, to re-dissolve the bubbles and hopefully prevent their reformation.

Close-up views of the chamber and pressure valves (photos: R. Rotjan)

Luckily, we never needed to use the chamber, and Craig spent most of his doctoring time trying to ease our seasickness, or treating bruises, cuts, scrapes, and allergies. Beyond that, we were all healthy and returned home safely and intact. We were prepared for much worse, however. Craig made sure that each diver was equipped with communications technology (in case we got lost or separated), a safety sausage (again to increase our visibility in case we got lost), a flashlight, a knife (to free from entanglements), a whistle (to call for help), and a tourniquet (in case of shark attacks). However, the one thing that we were all most scared of was a coconut incident. After all, there were a lot of coconut palms on some of the islands!

Coconut palms on Nikamororo (photo: R. Rotjan)

You see, one of my favorite marine biology statistics is as follows: you are more likely to get hit on the head by a coconut than to suffer a shark attack. True, or urban legend? Who knows, but to quote a 2001 journal in the ANZ Journal of Surgery entitled Coconut palm-related injuries in the pacific islands "A total of 3.4% of all injuries presenting to the [Solomon Islands] surgical department was related to the coconut palm. Eighty-five patients fell from the coconut palm, 16 patients had a coconut fruit fall on them, three patients had a coconut palm fall on them and one patient kicked a coconut palm".

"Dangerous" coconut palms 0n the Phoenix Islands (photos: R. Rotjan)

In other words - beware of falling coconuts, but if one falls, mix it with lime (full of vitamin C, it prevents scurvy!), and yell "DOCTOR!" loudly. Thanks to Craig, tropical fruit-borne fractures, scurvy, and the bends were not an issue... and we're most grateful.

Dive safe,




Breathe Deep

The Phoenix Islands "Greatest Hits" highlights continue...

#5: ROV exploration of PIPA depths

Take a deep breath. Go on, try it. In with the good air; out with the bad air. Ahhhhh. It's easy, and feels good, eh? Now, try it underwater. With SCUBA, you can only breathe so deep - around 120 feet on air, if you're a conventional diver. At best, might be able to breathe about 300 feet deep. What about on a submarine? Okay--you can breathe deep there, but you're breathing recycled air. And hence the topic of today's post: since we can't breathe deep underwater (at least not easily), how do we explore deep underwater?

(Left Photo: David Obura) (Right Photo: Jim Stringer)

The answer to this question depends on how deep you want to go. The coral reefs on PIPA are a reef formation known as an atoll (described in an earlier post). One of the features of these mid-ocean, volcanic atolls is that they are basically seamounts that break the surface--so they descend very deep, with a very steep slope. Kiribati is also full of seamounts that do not break the surface. In fact, Kiribati is home to ~4% of the world's seamounts. That's a lot of ocean to explore below the surface!

Seamounts featured between McKean, Rawaka (Phoenix) and Enderbury Islands (Photo: Google Earth)

It would be great to get a manned submersible out to PIPA someday, and hopefully we will soon. But as a first glimpse of the deep, we brought an unmanned ROV with us on this expedition. This ROV (Remotely Operated Vehicle) can only go 500 feet deep, but that's 380 feet deeper than we were diving. And yes--you guessed it--since the ROV was unmanned, breathing was not an issue. :)

Mo preparing to launch the ROV off the boat for a dive (Photo: Larry Madin)

Now, I'm not a stranger to the concept of deep depths. I used to work on deep-sea hydrothermal vents (miles below the ocean!) , but I've never personally journeyed there (though my experiments have). So naturally, I was extremely curious to be on-site for some deep-sea exploration. One of the big advantages of working on these reef atolls with their steep, sloping sides is that we could (and did) literally dangle the ROV out of our ship window (see Mo above with the ROV). Greg could (and did) sit at our dinner table on-ship and drop the ROV below us, while others of us were diving on the reef. As any deep-sea scientist will tell you: what an unlikely (and pleasurable) way to explore! Greg posted extensively on this earlier - see Greg's posts for more photos and details.

Randi Rotjan, David Obura and Les Kaufman look on as Greg Stone controls the ROV (Photo: Larry Madin)

A first glimpse was just enough to leave us breathless (figuratively, of course). Corals living past 300 feet! The crystal clear waters of PIPA were able to allow enough sunlight at depth to support the coral-algal symbiosis. We saw lots of healthy corals, though the diversity was low (just a few species) And fish! Snapper (the same we'd been seeing shallow), and more baby sharks patrolling the slopes. In fact, on one ROV dive, 10 sharks (gray reef and black tip) were seen. And here's the enticing part--when we looked further down the slope at the end of our ROV's tether, we could see that there was more life, still. Breathtaking.

(Photos: Jim Stringer)

Marine organisms are not limited to the shallows the way that humans are. Sadly for us, we have to make the choice between deep breaths or deep depths; we generally can't have both. But ROV's and manned submersibles give us borrowed lungs and enable us to explore the last unexplored frontier--the ocean floor. After all, we know more about the moon that we do about our ocean floor! I'm excited about future ROV and sub explorations of PIPA. After all, the thrilling and mysterious sights of the deep sea will take your breath away--but thanks to this technology, not literally.




Christmas Tree Worms

Note: Students from Celeste Young's biology class (Monument Mountain Regional High School; Great Barrington, MA) posted a question for Aquarium researcher Dr. Randi Rotjan in the comments section of this post. Here is Susanna's question with Randi's answer in light blue:

Hello! This is Celeste Young & her biology class! What is the scale of the christmas tree worm picture?

Hi Celeste and Susanna,

Thanks so much for reading the blogs, and for posting your question!

Christmas tree worms are small-- the crowns are only a few centimeters across, at most. They are hard to measure, since they actually retract their plumes (or branchial crowns) into their tubes with the slightest disturbance in the water. Tubes are made of calcium carbonate. These worms settle on the surface of a coral (they do not bore into the skeleton) and grow at roughly the same pace as the coral tissue - thus, they grow really slowly! Some worms are known to be up to 40 years old, so they also can live a very long time. Worms feed by filtering plankton from the water column with their branchial crowns. They retract into their tubes to avoid predators (and rulers). The best way to add a ruler to the photo is to place the ruler down, let the worm retract, and then re-emerge. However, this only works in very calm water, with high flow, the ruler will not stay in place! :-)

Check out the photos below of an exposed worm (left); and then the same worm retracted into its tube (right). These photos were taken by a student of mine, Sarah Abboud, who is actually studying these worms for her masters thesis. These photos are taken from Moorea, French Polynesia, but are of the same species of worm that we observed in the Phoenix Islands.

Spirobranchus giganteus christmas tree worm - exposed and retracted. (Photos: S. Abboud)

Below is another worm next to a piece of flagging for scale. The flagging is 2.5 cm across, so you can now estimate the size of the worm crown!

Spirobranchus giganteus christmas tree worm - exposed 
Here are some additional photos by Sarah, measuring the diameter of the tube. Tube diameter correlates to worm age, but not to crown size. Crown size varies with depth; worms in deep areas with high water flow (surge) actually have shorter crowns so that they don't bend or break when water is rushing past them. Deep areas with low surge have taller crowns. Here are some scale bars next to worm tubes; the left photo has an exposed worm behind the 1 cm scale bar (it's orange).

Spirobranchus giganteus christmas tree worms - retracted. (Photos: S. Abboud)

Finally, here's a worm retracted, but just barely: you can see it's crown folded within the tube, and just breaking the surface.

Spirobranchus giganteus christmas tree worm - retracted. (Photos: S. Abboud)

The photos on The Slow and the Spineless post were not taken for an explicit scientific purpose, thus, there are no scale bars on those photos. But I hope that this gives you an idea of scale, nonetheless.

Thanks again for your question!

Best fishes,