Mom! They're Copying Me!

The old saying goes: "Don't pretend to be something you're not." It's great advice for humans trying to navigate the complexities of identity and our place in society.

I'm lookin' at you, High School Me!

However, if you're a small creature that's constantly at risk of being eaten, pretending to be something else might not be so bad. 

There's familiar examples of passive camouflage everywhere in the ocean. Sea Dragons look like loose, floating kelp; stonefish lie as unmoving as their namesakes on the bottom; grunt sculpins are nearly indistinguishable from a barnacle when they're still. There are even animals that actively camouflage to look like their environment. The many species of decorator crabs attach seaweed, sponges, hydroids, and any other flappy materials to their shell to blend in with their surroundings.

Microscopic hooks cover the crab's shell to facilitate camouflage

Courtesy: Ruth Hartnup via Flickr, and

Monique Salazar and W. Randy Brooks via Journal of Marine Science

But sometimes blending into the background isn't enough. Sometimes, you've got to do more than look the part. Sometimes you have to live your role to complete the illusion. Enter the cephalopods.

Octopus, squid, cuttlefish, and nautilus are all cephalopods (pronounced: sef-a-lo-pod). Cephs are probably the most intelligent and adaptable invertebrates in the world. A closer look at their anatomy can help us understand why. Cephalopods don't have claws or spines; they're not very fast; they have a sharp beak, but they have to get close to use it; and except for nautiluses cephs don't have a hard shell to protect their squishy, protein-rich bodies. So what do you do when you lack anatomical defenses? You get smart.

The most famous of this class to have the smarts to watch another animal and copy its behavior is the appropriately named mimic octopus (Thaumoctopus mimicus).

<in a nasally mocking voice> "watch another animal and copy its

behavior is the appropriately named mimic octopus"

Courtesy: Rickard Zerpe via Flickr

Dude, don't copy me that's ridiculous.

"Don't copy me that's ridiculous."

Courtesy: Avi Alpert via Flickr

<The following was typed very fast so the mimic octopus couldn't possibly copy it quick enough, and we can all actually learn something>

Mimic octopuses are found on sandy bottoms in the waters around Indonesia, the Philippines, and Papua New Guinea. These sandy and silty bottom habitats have few rocks, little animal growth, and minimal algae to hide among. While mimic octos can change their colors to match the background just as well as their cousins; movement tends to break the illusion. Other octopus species take advantage of rocky reefs or coral crevasses to slink along unnoticed while in motion, but mimics don't have that luxury. They also typically have to swim farther and more often than octopuses in other habitats because their prey isn't concentrated in a small area. A swimming octopus is very distinct, so mimics exactly copy the swimming behavior of flounder to conceal their true nature. They bend all their arms around and cluster them together so their eyes are sticking up in front of a big flat disk. As their arms trail, the ends flap just like the fins of a flatfish. The octopuses even stop and start moving with the same frequency as flounders all while hugging the contours of the rippled bottom.

We don't know why, but sometimes the mimic octopus will keep its distinct pattern while moving like a flounder and sometimes it will change to the fish's usual coloration.

Courtesy: Klaus Stiefel and Bernard Dupont via Flickr

The internet is full of reputed stories of mimic octos copying other species as well. While reports of mimic octopuses mimicking lionfish, sea snakes, and stingrays are out there we should remember that octopuses evolved entirely without our perceptions in mind. This means that what may clearly look like a lionfish to us, may look nothing like it to a grouper hungry for a bite of octopus arm. However, it may be that the mimics' strategy is just to look like "not an octopus", and whatever other creatures they see, they try and copy.

Amazingly mimic octopuses aren't the only species of octopuses to mimic other creatures. Living in the same waters as mimics the excitingly named "blandopus", which has which hasn't been formally described yet, also copies flounder. And if you Atlantic Ocean folks have been feeling left out, don't worry. The Caribbean has a copy-cat octo as well. Atlantic longarm octopuses (Macrotritopus defilippi) live in a very similar habitat to mimics and blandopus, and also engage in flat fish plagiarism.

Some species just have no regard for copyright law.

Courtesy: Wayne via Flickr 

Clearly impersonating another animal is an effective way to avoid becoming someone's lunch. But can cephalopods use mimicry to catch their own prey?

Just off the coast of southern Brazil; in the southern summers of 1999, 2000, and 2001 a pair of scientists used lights shined from a boat to attract zooplankton. Light attractants like this are an important tool in many fisheries, particularly those for squid. Rodrigo Silvestre Martins and Jose Angel Alvarez Perez wanted to study how a community of predators and prey develop under these lights. Who's eating whom, how are they going about catching one another, and what could that mean for fisheries conservation? The researchers found that a column of animals, gradually increasing in size, formed under the lights. The smallest zooplankton were near the surface, and as you descended  progressively larger predators lurked, waiting for a chance to strike at the prey above them.

Lurking in the shadows is pretty typical behavior for any predator, but one squid species' actions caught Martins and Perez by surprise. Atlantic brief squid (Lolliguncula brevis) are an estuary specialized squid that eat small schooling fish like anchovy and sardines. During Perez and Martins' study they watched brief squid regularly mimic the shape, color patterns, and swimming behavior of anchovies in order to get inside their schools without being noticed before striking.

Brief squid isn't a cool enough name for these masters of infiltration.
I propose we call them "subterfuge squid" from now on.
Courtesy: NOAA Photo Library via Flickr 

Now, squid aren't the only cephalopods to pantomime another animal in order to get close to prey. We've found one species of cuttlefish engages in a similar behavior to creep up on reef fish.

Pharaoh cuttlefish (Sepia pharaonis) are a widespread, small cuttlefish found throughout the warm waters of the Indian and Western Pacific Oceans. In 2011 a team of Japanese researchers noticed their cuttles doing something weird when they were placed in a large open tank for an experiment. The cuttlefish pushed together their upper pair of arms and colored them like eyes on the end of stalks. Then they set their other arms at odd, jointed angles and started twitching them, seemingly at random. Lastly they colored their mantle a shade lighter than all of their arms. The whole illusion came together to look exactly like a hermit crab.

In case the video widget doesn't work, click here to watch the pharaoh cuttles in action; it's astonishing. The research team thought maybe the cuttlefish were mimicking to protect themselves from potential predators when exposed in a large barren tank; kind of like mimic octopuses pretending to be other animals when they're moving in the open. But the scientists were curious if faking crabbiness (definitely the scientific term) could also help the cuttles catch prey like brief squid pretending to be anchovies.

So in 2013 they collected more pharaoh cuttlefish and put them in a tank with small tropical damselfish. The cuttles that pretended to be crabs got closer to the schools and caught twice as many fish as those that hunted while acting like cuttlefish! So yeah, I'd say that's an effective hunting strategy.

As we begin to look closer at cephalopods we're starting to understand just how diverse and seemingly intelligent their behavior is. Mimicries like these are just a sample of the ways octopus and their cousins use their adaptable camouflage. So maybe pretending to be something you're not isn't always bad. Maybe we shouldn't deal in absolutes all the time and recognize that there's advantages and disadvantages to lots of behaviors and life styles. There's a lot to be learned still about cephalopods, but there's also a lot to be learned from them.

References:

Hanlon, Roger T., Watson, Anya C., & Barbosa, Alexander, "A 'Mimic Octopus' in the Atlantic: Flatfish Mimicry and Camouflage by Macrotritopus defilippi", Biological Bulletin, 218: 15-24, Feb. 2010.
Accessed via: http://www.journals.uchicago.edu/doi/10.1086/BBLv218n1p15

Hanlon, Roger T., Conroy, Lou-Anne, & Forsythe, John W., "Mimicry and Foraging Behaviour(sic) of Two Tropical Sand-flat Octopuses of North Sulawesi, Indonesia", Biological Journal of the Linnean Society, Jan. 2008.
Accessed via: https://academic.oup.com/biolinnean/article/93/1/23/2701347

Martins, Rodrigo Silvestre & Perez, Jose Angel Alvarez, "Cephalopods and Fish Attracted by Night Lights in Coastal Shallow-waters, off Southern Brazil, with the Description of Squid and Fish Behavior", Revista de Etologia, Vol. 8 No. 1 Pg. 27-34, 2006.

Accessed via http://pepsic.bvsalud.org/pdf/reto/v8n1/v8n1a03.pdf

Okamoto et Al., "Unique Arm-flapping Behavior of the Pharaoh Cuttlefish, Sepia pharaonis: putative Mimicry of a Hermit Crab", Japan Ethological Society and Springer Japan, May 2017.

Accessed via: https://link.springer.com/article/10.1007/s10164-017-0519-7

I Love It When You Call Me Big Papa

Whether you love him, hate him, or don't care either way; Barack Obama's presidency ended on January 20th. While the 44th president has had a rough time forming a lasting legacy on many fronts; he's proven himself to be the public lands president. Since taking office in 2009 Obama has set aside more land, and even more relevant to Depth and Taxa, ocean than any president in history.

Obama is basically that kid in school who trashed
the curve for everyone else.
Graph based on National Park Service Data

There's a number of ways that land and sea can protected from exploitation in the US. Areas can be set aside as National Parks; which basically prevents them from use other than research and outdoor recreation. Lands can be established as National Forest; which has a conservation aspect but also allows for some extraction of resources. However both of these designations require action by Congress. Action is not something the 114th Congress was famous for. So if a president believes the people that elected him want lands protected, but can't get congress to do anything, how does he go about it? Enter the Antiquities Act.

In the final years of the 19th century Americans were concerned about the rampant destruction of archaeological sites and ecosystems across the country. In response, Congress created the Antiquities Act to allow important cultural, historical, and scientific places to be protected as National Monuments; without the delay that comes from congressional deliberation. Unsurprisingly, Teddy Roosevelt used the act to set aside more acreage than any president until his fifth-cousin took the job in 1933.

"Hahahaha, just try and outdo me little Frankie. I'm the only 
president  this century that everyone liked." -Teddy Roosevelt

You might expect that Democratic presidents are more likely to use the antiquities act, but the exact same number of Democrats and Republicans have established or enlarged National Monuments. In fact, one of the largest ever national monuments was established by the number two acreage protector, none other than George W. Bush! The Papahānaumokuākea (pronounced: papa-ha-now-mo-ku-ah-kay-ah) National Monument was established in 2006 by president Bush and expanded by over 400,000 square miles in 2016 by president Obama.

Papahānaumokuākea (Or for Notorious B.I.G. fans: Big Papa) hits every mark for the intent of the Antiquities Act. It has important historical sites; like Midway Atoll where the Allies scored a major naval victory in World War II. Culturally important places to indigenous Hawaiians. The northwest islands in the monument are believed to be where spirits are born and return to after death. And major ecologically and scientifically important ecosystems. Shallow and deep water stony coral reefs, breeding grounds for endangered species, islands full of endemic plants and animals, and a sea mount as high as Mount Rainier are all found inside the monument.

If we place Papahānaumokuākea on top of the US it's as long as Idaho to Indiana

and as wide as Montana to central Utah.

Image Courtesy; NOAA

Not only does Papahānaumokuākea represent the ideal of what a national monument should be; the restriction it puts on commercial fishing, but not recreational fishing, comes at an essential time in the health of the ocean. There's a growing consensus that about 30% of the world's seas needs to protected from large-scale fishing if we want to continue to feed humanity with good, healthy protein.

 Currently less than 2% of the ocean is covered by marine protected areas, so there's lots of work to be done. Fortunately we already have some guidelines on what makes for an effective marine protected area. One standard uses what are called NEOLI features to plan and assess successful marine protected areas. NEOLI stands for: "No-Take, Enforcement, Old, Large, and Isolated". If a protected marine site can meet four of those five features it's likely to be successful in promoting biodiversity, and in allowing fisher people to collect better catches with less effort at the edge of the protected zone.

"What's that about catching more fish with less effort!?" -This Hawaiian Monk Seal
Courtesy: Dr. James P. McVey, NOAA Sea Grant Program. (NOAA Photo Library: anim0290) 

Obviously Papahānaumokuākea meets the "large" standard, but how's it do in those other areas? Papahānaumokuākea isn't a no-take zone because recreational and sport fisheries are still able to get permits to use the area. However, the scale of recreational fishing is so small relative to commercial fishing that this represents a potentially huge cutback in the amount of harvest within the monument. And before you get frustrated that small scale commercial fishers will be going out of business there's great news. Research has shown that when areas are protected from fishing, species tend to repopulate the protected area and spill over into fishing sites. The edges of the protected area usually have more numerous, larger, and healthier fish than areas far from any protected zone.

Of course no-take doesn't matter if you don't have strong enforcement. This is where Papahānaumokuākea will probably struggle most to meet the standards for protection. The monument is managed by a partnership between the federal and Hawaiian state governments. Hopefully a strong realtionship between these parties will be able to monitor such a vast area. Thankfully some very cool systems are coming online in the near future to help countries protect their natural resources. The Pew Charitable Trusts have developed an incredibly cool program called: Project Eyes on the Seas that uses satellite images, vessel GPS transponders, and home port data to police marine protected areas for relatively cheap.

       Bad Boys, Bad Boys, What'cha Gonna Do? What'cha Gonna Do,
When They Come Fo' You!?
Courtesy: Tony Hisgett via Wikimedia Commons

Now obviously any newly expanded or created national monument isn't going to be considered "old". However, Papahānaumokuākea meets the last NEOLI standard by being isolated from cities and continents, and so thankfully hasn't historically been heavily impacted by human activities. Because exploitation has been limited, Papahānaumokuākea has many of the features we normally associate with old marine protected areas. In fact, in the deep channels between the islands, atolls, and sea mounts of the Hawaiian chain live black corals that have been growing in the same spot for 4,000 years.

Using the NEOLI standards, it looks like Papahānaumokuākea has the potential to help the ocean recover from our historical transgressions, and to provide for humanity in the future. Good environmental policy is about finding balance; meeting the needs of many while protecting the most vulnerable. The ecosystems that produce the natural resources we need have to be kept intact if they're to continue to provide raw materials, jobs, food, inspiration, and a connection to something larger than ourselves. National Monuments like Papahānaumokuākea are an important part of the land-use mosaic that allows the United States to provide the best life for its citizens.

The incoming administration has expressed a focus on the harvest and materials side of the benefits of the environment. An extractive management style may put places like Papahānaumokuākea at risk of having their protections revoked. Both goat farming hippies and doomsday preppers can agree that people have the right to survive off the land. If we can work to remind everyone that all the materials of our modern lives originated from, and are replenished in, pristine ecosystems; then places like Papahānaumokuākea will have a better chance of remaining unaltered. Let's work together to build a broad coalition of people who know the value of functioning ecosystems.

References:

Roberts, Callum M., Hawkins, Julie P., & Gell Fiona R., "The Role of Marine Reserves in Achieving Sustainable Fisheries", Philosophical Transactions of the Royal Society B, Vol. 360 pg. 123-132, 2008.

Bruckner, Andrew, De Angelis, Patricia, & Montgomery, Tony, "Case Study for Black Coral From Hawaii", Non-Detriment Findings Case Studies, WG 9- Aquatic Invertebrates, Case Study 1, Meeting of the IUCN 2008. 

Accessed via: http://www.conabio.gob.mx/institucion/cooperacion_internacional/TallerNDF/Links-Documentos/WG-CS/WG9-AquaticInvertebrates/WG9-CS1%20BlackCoral/WG9-CS1.pdf

Edgar et Al. "Global Conservation Outcomes Depend on Marine Protected Areas with Five Key Features", Nature, Vol. 506, Pg. 216-229, Feb. 13th 2014.

Accessed via: http://www.nature.com/nature/journal/v506/n7487/full/nature13022.html

Long, Tony, "How Satellite Monitoring is Helping Catch Bad Actors", Pew Charitable Trusts Research & Analysis Online, March 7th 2016.

Accessed via: http://www.pewtrusts.org/en/research-and-analysis/analysis/2016/03/03/how-satellite-monitoring-is-helping-catch-bad-actors

US Congress, "American Antiquities Act of 1906"

Accessed via: https://www.nps.gov/history/local-law/anti1906.htm

Naut Again

Oh wow, there's some wonderful news that's come out of the US East coast recently that hasn't gotten the coverage it deser....

"NAUT SO FAST PUNK!"

Courtesy: DarTar via Wikimedia Commmons

Oh, god no, not this again. How many weeks am I going to have to go without getting interrupted by a cephalopod? What do you want chambered nautilus (Nautilus pompilius), and did you seriously just use your own name as a pun?

"I'll use my name however I want after you and that wannabe 

Greek hero besmirched it. She should be proud to be 

associated with us nautiluses."

Courtesy: Michael Bentley via Flickr

Alright, alright, I didn't mean to offend anyone. I wrote about argonauts last week since they're a cool family in their own right. I guess I didn't think about how little people know about your family too. Tell you what, I'll make this post all about you, if you promise to tell the other cephs to stop interrupting me. I don't want a ram's horn squid butting in next week.

"Alright deal, but I'm gonna stand here and make sure you do us justice"
Courtesy: OCVA via Flickr

Okay well, if we're gonna give this family the credit it deserves we need to talk about world domination. Don't worry, you needn't imagine a future where shelled overlords subjugate earth's other species, because it already happened. Nautiluses are old, very old, in fact their family members are the OG cephalopods. The first nautiluses to appear had straight shells, but around 400 million years ago they developed the familiar spiral we see today. They were so successful that they, and their cousins the ammonites, would go on to dominate the seas for eons. Nautilus even survived the worst extinction of all time which killed 96% of all life in the sea. Not too shabby for an animal that's essentially a fancy snail.

Even though they ruled the oceans for so long, the nautiluses eventually gave up their family's dynasty to live a life of quiet retirement. Today only two genera of nautilus exist, down from the 75 or so at their peak. Modern nautiluses are found only in the Indian and Pacific oceans in the deep waters at the steep edges of coral reefs. Yet they are some of the most fascinating organisms to occupy those spaces.

Of course what stands out most about nautilus is their incredible shells. Nautilus are the only cephalopod left to still have an exterior shell, which means they don't need all the gaudy color and texture changing flashiness of their cousins. Instead of hiding, speeding away, or out-thinking their predators nautilus prefer the simple life scavenging food off the bottom; and cruising through deeper water at times when predators are at rest.

They're kind of like that friend from college who moves to
 Idaho and starts a goat farm because "It's just easier."
Courtesy: Hans Hillewaert via Wikimedia Commons



Now you might notice that the nautilus' shell is pretty burly. There are hardly any animals with shells that thick that even bother swimming. Other heavily shelled mollusks like clams and snails spend most of their time on or in the ground. So what does the nautilus do that makes it able to hover up in the water like that? Are they just incredibly strong? Not really. When you watch a nautilus puff along by forcing water through its siphon, it kind of makes you want to hand it an inhaler and tell it to go sit on the bleachers. So if it's not pure herculean strength that keeps the nautilus afloat what is it? Well my friends, the nautilus succeeds thanks to the magic of good engineering.

I think like a third of our readers just found their spirit animal
Courtesy: Jason Westley Upton via Flickr

Inside the shell are the structures that put the "chambered" in chambered nautilus. The largest chamber is where the nautilus' mantle is housed, but the others are empty of everything except air and a little bit of water. When a new chamber forms the nautilus walls its previous space off and amazingly, drains the water. See if the chambers stayed filled then the nautilus would get dragged to the bottom thanks to the weight of the water inside the shell. Emptying water from the chambers has the same effect as if the nautilus were to tie balloons to its shell. The air inside pushes up towards the surface while the weight of the shell pulls down, and the two forces balance one another out to make the nautilus neither sink nor float.

You might be wondering: If the nautilus seals the chambers how does it get the water out? Well running through the chambers is a really cool organ with a really cool name, a siphuncle (pronounced: sigh-fun-kull). The siphuncle is a tube that uses water's own physical properties to fill and empty the chambers. See water has a tendency to try and balance the concentrations of different minerals dissolved in itself. So if you put a screen that will only let water through between two solutions and you make one much saltier than the other; the water will cross the screen to the salty side until the two sides' ratios of salt to water are equal. This is exactly what the siphuncle does. When the nautilus wants to remove water from the chambers it adds salt ions to the outer layer of the siphuncle and the water just seeps on out of the chamber. When the nautilus wants to add water to the chambers it does the opposite. This system requires basically no energy on the animal's part, so it's a great strategy for staying properly buoyant.

Who says functional machines can't be pretty? Those little struts in the center 
of each chamber hold the siphuncle in place as it runs through the shell.
Courtesy: Jitze Couperus via Flickr

Of course everyone focuses on the shell of the nautilus, so much so that these animals are being impacted by fisher people catching them for their shells. Many scientists and citizens who care a lot about nautilus are doing everything they can to show the international community that nautilus, not only deserve, but need our protection. The easiest way to do your part is to never buy new nautilus shells. Instead look around antique stores, or purchase nautilus fossils, which have the benefit of being infused with beautiful minerals from fossilization.

Aside from their shells, nautilus are also impressive thanks to over 90 tentacles! These tentacles are much simpler than the complex arms of the nautilus' cousins. They have no suckers and instead use a series of grooves to grip surfaces. They're also incredibly sensitive to scent/taste. As a scavenger nautiluses need to be very aware of where food is sitting, and all of those tentacles act like an array of antennas picking up the fishy signal of food rotting on the bottom.

Okay nautilus, was that a satisfying amount of information for you? We can always come back another week and learn more.

"Well that was better than naut. It'll do for now, and naut to worry,
you've naut seen the last of me."
Courtesy: David Remsen via Flickr

Ugh, the puns man, the puns...

References:

Dunstan, A., Ward, P., & Marshall, N., "Vertical Distribution and Migration Patterns of Nautilus pompilius", PLoS ONE 6(2): 16311, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016311

Ward, Peter, "Cameral Liquid in Nautilus and Ammonites", Paleobiology, 5(1), 1979, pg. 40-49.
Accessed via: http://www.jstor.org.ezproxy.library.wwu.edu/stable/2400389?seq=1#page_scan_tab_contents

Crook, R., & Basil, J., "A Biphasic Memory Curve in the Chambered Nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea)", Journal of Experimental Biology, June 15th 2008.
Accessed via: http://jeb.biologists.org/content/211/12/1992.long

Dunstan et al., "Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia" PLoS ONE, 6(2): e16312, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016312

A Clam for Ken Kesey

"That's a CLAM!?" This reaction to a particular animal is almost guaranteed when people look at them for the first time. Check it out.

Oh man, who just leaves a tie-dye shirt laying around on a coral reef?
Courtesy: Nick Hobgood via Flickr

Okay first off, that looks nothing like what belongs in my chowder. Second, this animal just goes to prove that the 60's got to everyone. So where does counter-culture clam come from and why's it so psychedelic? Editor's Note: This post is greatly improved when accompanied by Strawberry Alarm Clock's: Incense and Peppermints, or your own favorite psychedelic rock song.

Well what you're looking at is a Tridacna (pronounced: Tri-dack-na) clam. They're more commonly called giant clams, but I don't really like that name because not all of them are giant. In fact one species, Tridacna maxima, has the common name "small giant clam"; that's just silly so were gonna stick with their scientific name for this post. Anyway Tridacna don't look much like their relatives, but all the pieces are still there. They have heavy rippled shells like their cousins the cockles, and the part that you see sticking out is their mantle (the body of a mollusk) and their siphons (The channels clams use to feed and breathe). These combined anatomical parts are what make up the "meat" of the clam that we eat.

Plankton filled water flows into the hole on the right, and strained 
water flows out of the tube on the left.
Courtesy edgeplot via Flickr

Tridacna clams live on coral reefs in the tropical Western Pacific. Once they settle out from the plankton they spend their entire lives in that single spot. They don't dig into the ground, but instead let it all hang out. Truly these bivalves (animals with two shells) have gotten the hippy lifestyle down pat.

In fact it turns out that Tridacna's trippy colors and patterns are essential to its survival. The reason Tridacna don't dig into the sand is that they're part of a self sustaining commune. Just like the stony corals around them; these mollusks host symbiotic algae under their skin. In order for the algae to photosynthesize they need to be exposed to the sun. The hinge of the clam's shell is heavier than the opening, so it can tilt face up and spend the daylight hours with its skin spread out in the light. The algae get protection from consumers, and the clam gets nutrients without having to feed. Having a backup way to get your food is especially helpful on coral reefs because the water around them is usually lacking in plankton. Completely clear water is great for snorklers' ability to see, but not so great for filter feeders' ability to eat.

"Come on baby light my zooxanthellae" -Jim Molluskson
Courtesy: Eric Johnson via the NOAA Photo Library

Now as anyone who's forgotten sun screen on a tropical vacation can attest, the sun at the equator is incredibly strong. Solar radiation in the middle of the day is so intense that photosynthesis can actually decrease as the clam's symbiotic algae try to protect themselves from sun burn. But this is a collective man, and the clam does its part to help the algae function efficiently.

The algal cells under the clam's skin are arranged in stacked towers, which is confusing because that means the cells on top shade out those below them. To counter this Tridacna have their own cool cells called iridiocytes (pronounced: ear-id-ee-oh-sites) which bend light in different directions. The iridiocytes reflect yellow and green light (which aren't used by the algae) away from the stacks, and reflect blue and red light (which are useful) towards them. Essentially the iridiocytes screen out the best light for the algae, soften its intensity, and evenly distribute it across the stacks of cells.

The combination of colorful algae and reflected light come together to create the mind expanding visual experience of looking at a Tridacna's skin. Cameras can't really capture how magnificently colored these animals are, so I really encourage you all to take a trip to your local aquarium and see them for yourselves. But here's another picture to tide you over 'til then.

  Couretsy: Nick Hobgood via Flickr

References:

Holt et al., "Photsymbiotic giant clams are transformers of solar flux", Journal of the Royal Society Interface, Oct. 2014, DOI 10.1098/rsif.2014.0678 Accessed via:

http://rsif.royalsocietypublishing.org/content/11/101/20140678 

Soo, Pamela & Todd, Peter A., "The behaviour of giant clams (Bivalvia: Cardiidae: Tridacninae)", Marine Biology, 2014, DOI 10.1007/s00227-014-2545-0 Accessed via:

http://link.springer.com/article/10.1007/s00227-014-2545-0/fulltext.html

The Punkest Fish in the Sea

Dust off your record player, whip out that old Sex Pistols vinyl, and get moshing because this week we're talking about the punkest fish there is: the rock-mover wrasse.

"Oi, Oi, Oi!!!"

Courtesy Steve Dunleavy via Flickr

Rock-movers, also called dragon wrasses (Novaculicthys taeniourus), are a tropical fish found all throughout the Pacific and Indian oceans. So how is it punk? A better question would be how isn't it? But you wouldn't know that would you poser!? 

First off; just look at that thing. That is the single most rockin' mohawk in the history of evolution. Not only does it have two giant fans on its head, the dorsal (back) and anal (you can probably guess) fin have adapted into mohawks too. It's also patterned like someone used a cigarette to put burn holes in a national flag and then splashed whitewash across it. There's that subdued and tasteful green background with the orderly, geometric, brown, dividing lines; and then a bunch of random white splotches ringed by black. These adaptations allow juvenile rock-movers to pretend they're drifting dead algae that's full of holes. Yeah they dress as trash. Throw a safety pin on there and you've got the whole look locked down.

I'll be honest I'm not sure I remember which picture is the fish...
Courtesy Ken Tam and Trip & Queball via Flickr

Of course it's not enough to dress punk. If you don't want to get called out as a poser you've got to act punk too. When rock-movers are put in aquariums while they're still small, other fish will often pick on them. However once they size up a bit and get confident they'll take on virtually everything around them. They establish a territory and guard it against any and all comers; I mean literally too. I was first introduced to this fish in an open top tank behind the scenes at an aquarium. I leaned over to look in, and a rock-mover shot out from the coral and charged the surface. A four inch fish tried to take on a 6 foot human because I looked at him funny.

In the wild rock-mover wrasses can be found living above sand and coral rubble between reefs. These fish deliberately live in the broken waste between the closest things the ocean has to cities. That is hardcore as s**t. They constantly toss rocks and coral rubble around  (hence the name) even building them into forts which they can sleep under. Now fancy "educators" and "scientists" might try to tell you they lift the stones to look for invertebrates underneath that they can eat, but we all know they're really practicing putting bricks through windows. Sometimes rock-movers will channel all their teen angst at once to lift rocks nearly as heavy as themselves or bury completely.

Best watched with Anarchy in the UK playing in the background

But there's one final nail in the coffin for this being the most punk fish in the sea. Something that's an essential stage in the punk lifecyle. They totally grow out of it. See the crazy flamboyant colors and appendages are just a phase. Every picture I've shown you so far has been a juvenile. Eventually like any punk; rock-movers settle down, put on some more practical fins, and have a couple hundred kids.

Though they might go to an occasional Alice Cooper concert
Courtesy J.E.Randall via EOL

References:

http://eol.org/pages/204380/details

http://www.fishchannel.com/fish-magazines/aquarium-fish-international/april-2011/dragon-wrasse.aspx

http://www.iucnredlist.org/details/biblio/187441/0/print/print/print

http://www.mauioceancenter.com/marinepdf/rockmover_wrasse.pdf