Brittle Stars: Secrets of the Ophiuroidea

Ophiothela sp. on a zooxanthellate gorgonian. Although brittle stars are not main attraction in most reefs, they do make an interesting side show. By Daniel Knop Web Bonus Content from the September/October 2013 Issue of CORAL Magazine Additional Bonus Brittle Star Articles Brittle stars have a peculiar body plan. A round central body disc carries five, six, or even seven slender, radiating arms that move like snakes. The arms gave these animals not only their other common name, serpent stars, and their scientific name, Ophiuroidea (Greek: ophis = snake), but these appendages also repel some hobbyists —not everyone likes snakes. The tube feet of brittle stars have no suction cups. The arms of brittle stars, unlike those of starfishes, do not seamlessly attach to the central body disc but are sharply delineated. In some species, the arms also form numerous branches. Another difference between brittle stars and starfishes is that brittle stars are able to move their arms sideways, which allows for rapid locomotion. The arms consist of individual calcite vertebral ossicles that are hinged together. Ambulacral feet (tube feet) are located on the bottom of the animal. As in other echinoderms, the feet are controlled and moved by a hydraulic canal system inside the body. They lack the suction cup extensions that starfishes use to attach to the substrate, but they do have some adhesiveness, allowing many species to dab up food particles with them. Brittle stars use their feet mainly for olfactory sensations. The mouth is the only opening of the digestive tract; there is no anal opening. Actually, the term “tract” is a misnomer here, since it is only a stomach cavity in which the food is digested to recover the nutrients. Afterwards, the waste is eliminated again via the mouth. In principle, the brittle star’s food intake is similar to that of the starfish. These two classes of animals also share many other similarities. However, besides the differences described above, most brittle star species have spines on their arms and the madreporite, which connects the ambulacral system that controls the hydraulic feet with the surrounding water, is not located on the top side, as it is in starfishes, but on the bottom. The gonads (bursae), in which the germ cells are formed, are located in the respiratory cavities on both sides of the armpits. The previous article describes the localization and function of the bursae in detail. Sinosura kelheimense fossil from Germany’s Solnhofen Limestone. Brittle stars are known from fossils since the Early Ordovician, a geological period that began 485 million years ago, but their scientific classification has not been particularly well studied. Because of their delicate bodies, these echinoderms only rarely formed continuous fossils that could provide scientific information about the relationships of extinct species. Therefore, we know much more about the evolutionary history of other animal groups. Usually, the arms of brittle stars disintegrate quickly into their individual components. Such fossil pieces are found often, but they are not very specific, and even experts usually have difficulty with their taxonomic classification. Ophiomastix annulosa, for sale at the Kölle Zoo pet super store in Heilbronn, can be seen even during daylight hours. Habitat Today, brittle stars are almost omnipresent in the world’s oceans. They are found in virtually all habitats, from the intertidal zone down to depths of more than 23,000 feet (7,000 m). In coral reefs and adjacent habitats, they are often found in large densities, for example in sediments or the intertidal zone. Many species live in community with corals or other invertebrates, particularly dwarf species that remain below 0.8 inch (2 cm). They form veritable colonies that cling with their thin arms to the branches of soft or horn corals during the day and stretch the arms out at night to catch plankton in the open water. Filtering brittle stars, such as this tiny Ophiothela sp. (oral disc diameter 3 mm) on a gorgonian branche have feathered tube feet. Beyond the reefs, brittle stars will occupy any ecological niche that is available to them. Excellent examples are underwater mountains, ecosystems that have been known and explored for only a few years. These mountains rise from the seabed but do not reach the surface. They are usually formed by submarine volcanoes. Their isolated location makes them ideal for the development of marine communities, which consist of sponges, corals, and other invertebrates, and sometimes also of crustaceans and fishes. Larvae drift there with the currents and can establish themselves, but the distances to coral reefs are so great that predators of any kind can hardly reach them. These deep-water reef communities are fed by planktonic organisms carried by ocean currents. On one such underwater mountain south of New Zealand, whose summit is located about 295 feet (90 m) below the sea surface, tens of millions of brittle stars have been found in massive accumulations—in some places more than 100 per 11 square feet (1 m2). Evolutionary history Brittle stars are related to sea lilies (crinoids)—sessile animals with simplified bodies and reduced structures. They gave up their mobility and environmental awareness in order to colonize new ecological niches. The vast majority of their representatives have been extinct for a long time; only a few deep-sea species still exist. According to today’s understanding, the precursor forms of the crinoids developed the five-segment radial (pentaradial) symmetry from the original two-sided body shape (bilateral symmetry) that we find today in echinoderms such as sea urchins, starfishes, and brittle stars. The original two-sided symmetry is still visible in the eight-armed ophiopluteus larvae from which brittle stars emerge. Fossil sea lilies of the class Crinoidea. Later, when changes in environmental demands again favored mobility as beneficial or even essential for survival, the descendants of the sessile crinoids gave up their sedentary lifestyle and apparently developed a new mobility. This included the ability to perceive and respond to environmental stimuli. However, these species were restricted by their current anatomical structures; body structures they had abandoned in the course of evolution were lost. For example, it was not possible to develop the complex eyes that other animal groups had. So echinoderms had to find their own solutions for these challenges of their environment. One example of this is the peculiar visual organs that have recently been discovered in brittle stars. Although they do not have eyes in the conventional sense, they are able to distinguish between light and dark—for instance, they can detect a shadow cast by an approaching predator and escape into a rock crack. Their development took a very unusual path, as was first demonstrated by Ophiocoma wendtii (Addadi, et al., 2001). From this research, we know that O. wendtii controls the formation of crystalline structures using specific proteins. These crystals are arranged in the skeletal elements in spherical groups. They focus the light without scattering like a tiny lens and concentrate it approximately 50 times in the focal point. Passing the light on to photoreceptors, the nervous system thereby receives a corresponding stimulus. In this way, brittle stars register brightness without eyes. Aquarium care Today the trade offers numerous species, not just the few large ones found in the 1980s and 1990s (e.g. Ophiarachna incrassata, Ophiolepis superba, and the bright red Caribbean species Ophioderma squamosissimus). Very often, you will find small brittle star species that reproduce spontaneously and form very dense populations under appropriate conditions. Mostly, however, they inadvertently get into the tank along with corals. One example is Ophiocoma pumila, which shows a characteristic red striation on the arms and reaches about 2.4 inches (6 cm), but other smaller species are also common. In the aquarium, Ophiocoma pumila releases sperm a few weeks after vegetative propagation. Most brittle star species are unproblematic in the aquarium, but there are some exceptions. Feeding is very easy, because they are usually carnivorous and also feed on dead animals. Fine suspended particles attach directly to the tube feet, while larger chunks are grabbed with the tip of the arm and transported to the mouth opening by rolling up the entire arm. Many brittle stars can open wide and deform their oral discs in order to swallow large chunks. When adding a specimen to the aquarium, one should always proceed with caution. As with all echinoderms, slow adaptation to the aquarium water is important. Brittle stars also tend to sacrifice individual arms when threatened. A severed arm can go on moving for hours. This appears to distract the attention of a predator from the fleeing brittle star. Although a lost arm soon regenerates under good nutritional conditions, such a loss should still be avoided. Astrobrachion constrictum on Diodogorgia nodulifera. Especially the small species are fascinating aquarium guests, as they increase biodiversity. They are commonly found in many reef tanks. Especially if there are no specialized predators, brittle stars multiply quickly by vegetative propagation to form individual-rich populations. However, they mostly live hidden and are rarely seen—so many aquarists have no idea how many live in their tanks. A mass spawning event, when the animals compete for the best spot to release their germ cells, provides a rare opportunity to observe the entire population at the same time. On Internet forums, people sometimes refer to brittle stars as pests. These individuals use brittle star “wedding events”—spawns—to collect the animals in large numbers and dispose of them. This is absurd and wasteful. Those who do not want these fascinating echinoderms in their aquariums should pass them to others. Their mass occurrence alone is no burden for a reef tank, as long as no visible damage can be unambiguously attributed to them. In general, these scavengers live so much in secrecy that you barely notice their presence. At night, Astroboa granulatus spreads his arms like a crown to filter planktonic organisms from the water. The lower arms also probe the substrate and live corals, looking for prey. In terms of diet, one of the exceptions mentioned is the quite popular and regularly offered Green Brittle Star (Ophiarachna incrassata, see below). It can even multiply in the aquarium. This species is known to attack soft corals and fishes, but only when it is underfed—if regularly fed a chunk of fish twice a week, it should not pose any problems. Brittle star species for the aquarium Within the animal phylum Echinodermata (sea urchins, starfishes, sea cucumbers, and others), the brittle stars belong to the class Ophiuroidea. Ophiuroidea consists of the three orders Ophiurida, Oegophiurida, and Euryalida (or Phrynophiurida) that contain 17 families with about 250 genera. A total of around 2,000 species are known, making this class of animals the most diverse of echinoderms. Most brittle stars interesting to aquarium hobbyists belong to the first of these three orders: Ophiurida. There we find the genera Ophiarachna, Ophiocoma, Ophioderma, Ophiolepis, Ophiothrix, and Ophiomastix, the small Amphipholis, and other small representatives of the families Amphiuridae and Ophiotrichidae. Red Serpent Star (Ophioderma squamosissimus). Very peculiar brittle stars are found in the third order, Euryalida. They are more primitive than any other brittle stars and are mainly characterized by their smooth, spineless arms. In addition, they live closely tied to specific invertebrate host animals. Their arms are usually much shorter in relation to their bodies than animals in the other two orders, and the whole body is covered with a slimy secretion. These unusual brittle stars appear occasionally in the trade as members of the genus Astrobrachion, e.g. A. constrictum. However, they are an absolute rarity and so inconspicuous that they are found only through a targeted search. In addition to these small species, the order contains the family Gorgonocephalidae, large brittle stars with highly branched arms. They look particularly impressive at night, when they spread their arms into a semi-spherical basket shape to catch planktonic food. Banded Brittle Star (Ophiolepis superba). The vast majority of brittle star species that we find in the trade belong to the order Ophiurida. The genus Ophioderma (family Ophiuridae) contains the Red Serpent Star (Ophioderma squamosissimus), one of the most beautiful species with its orange-red coloration. Its range extends from the Bahamas to Belize. The maximum span of the Red Serpent Star is 16 inches (40 cm), although it doesn’t usually grow that big in the aquarium. Its appetite is similar to that of the Green Brittle Star (see below)—it, too, is an omnivorous opportunist that must be fed well and regularly. Any replacement food, such as food tablets or chunks of food fish, will be greedily accepted. Because the Red Serpent Star is active during the day as well as at night, it is ideal for the coral reef aquarium. The genus Ophiolepis (family Ophiodermatidae) contains the Banded Brittle Star (Ophiolepis superba), another very pretty species. It wears brown bands on a light beige background; these bands extend all over the arms, and the round body disc has a brown star. The distribution area extends over the entire Indo-Pacific, from the Red Sea and East Africa to the Pacific Islands. The span of this species can reach almost 10 inches (25 cm). With regular feeding, this normally nocturnal brittle star can get used to looking for food even during the day. It is omnivorous and searches sediments for organic leftovers. This species is robust and ideal for a coral reef aquarium. Green Brittle Star (Ophiarachna incrassata). The Green Brittle Star (Ophiarachna incrassata) also belongs to the family Ophiodermatidae. It is durable and easy to care for. It is similar to the two species mentioned above, but far more opportunistic when searching for food. If threatened by food shortages it will even graze on Xenia. The brittle star lowers its mouth disc onto a soft coral, engulfing it with its stomach cavity, and then lifts the entire body, ripping off part of the coral. If they have to dig even deeper into their bag of tricks to survive, they will even catch small, sleeping fishes between their arms at night. However, if they are sufficiently fed with a food table or piece of food fish twice a week, they will hardly cause any damage in the aquarium. A hungry Green Brittle Star puts his body up at night like a cage to catch small, sleepy fishes. Ophiarachna incrassata has reproduced several times in the aquarium, but this seems to be coupled to an optimal diet. Dr. Jochen Lohner kept two large Green Brittle Stars in an aquarium, and when he took it apart after a few years he found 13 adult specimens. The representatives of the genus Ophiomastix (family Ophiocomidae) are somewhat more delicate than the species listed above, and they have a very typical shape. The arms have conspicuous spines, and if you look closely you can see that many of the spines have a club shape. Many of these species have a nice color and reach a maximum size of approximately 12 inches (30 cm). They are easy to care for, harmless, and a real asset to the coral reef aquarium. They might graze on very delicate sessile invertebrates, such as small sea squirts, but they do not touch corals. This Ophiomastix annulosa arm shows the white stripes on the dark topside. The spines are striped black, some shaped like a club. Ophiomastix variabilis also has club-shaped spines. The black arms sport bands of white. The family Amphiuridae contains numerous small species that vegetatively reproduce in the aquarium. In the absence of specialized predators they can create very individual-rich populations. They are found in sediments, cracks, and crevices, or at the bottom of stony corals, under sponges, algae, or other places where they like to rest and let some of their arms hang in the open water. When they discover suspended food in the water, they begin to wave with their arms or even come completely out of hiding. One of these genera is Amphiura. Amphiura specimens on Caribbean sponges in the aquarium. Representatives of the genus Amphipholis represent the smallest known brittle stars and reproduce well in the aquarium. At least one of the currently 25 species appears occasionally in the trade: Amphipholis squamata. Found in tropical and subtropical seas around the world, it reaches about 12 mm (0.5 in). The body disc measures no more than about 2 mm. These tiny brittle stars live mainly in fine sediments and can generate huge populations in the aquarium. The aquarist gets to see them only when cleaning a filter or moving rock and underlying fine sediments. These brittle stars reproduce vegetatively by division, which can be seen on those specimens that have different arm lengths because they regenerate lost arms. The maximum span of these Amphiura specimens is approximately 1 inch (2.5 cm). Amphipholis squamata with a total span of 0.4 inch (1 cm). Many tropical species that are not too large are also found in the family Ophiotrichidae. However, in contrast to the Amphiuridae, they are closely tied to sessile invertebrates such as corals and sponges, on which they live as commensals. An example is the genus Ophiothrix, containing some species with characteristic appearance. The coloration is very variable and species-specific, probably in adaptation to each host. The arms are densely covered with long spines, and the size in most species is 4–8 inches (10–20 cm). Naturally, you meet these attractive brittle stars on sessile invertebrates, like sponges. They hide in their gaps or cracks and at night scour the surface thoroughly, looking for something to eat. Distribution areas, depending on the species, are the entire western Indo-Pacific or the Caribbean. When Amphipholis squamata mate, their entire oral sides come in contact. Smaller still are the representatives of the genus Ophiothela, who live primarily on sessile invertebrates such as sea fans and sea pens. The size of this animal’s mouth disc is 2–3 mm, and the arm length ranges from 0.4 to 6 inch (10–15 mm). We usually see these brittle stars clinging with their striated arms to the branches of their host corals. With food suspended in the water, they stretch their individual arms into open water and spread their tiny tube feet, which often have a feathery structure to increase the surface area. The distribution area of the six known species covers the entire Indian Ocean and Western Central Pacific, from East Africa to the islands of the South Pacific. Ophiothrix suensonii on Swiftia exserta. Unfortunately, these attractive brittle stars are almost never purposely imported. They appear in the trade only as hitchhikers on their host corals, and you have to specifically look for them. In the aquarium, they need fine suspension food and absorb even dissolved substances from the water. However, they only survive if the food is available daily for a very long time. One or two suspension feedings per day is not enough. Ophiothrix sp. on Dendronephthya sp. The 22 species of the family Ophiocomidae are usually significantly larger than the above. In the aquarium, we encounter mainly Ophiocoma pumila; it has a fairly typical appearance, with its reddish body disc and red-striped arms. If you look closely, you can see greenish elements between the red marks, and both have the same fine line pattern. The number of arms is five or six. When they sense fine suspension food in the tank, the animals stretch their arms into the open water. This small Ophiothela species reproduces well in Till Deuss’s aquarium. Ophiocoma pumila can develop very individual-rich populations in the absence of specialized predators. Their reproduction in the aquarium is vegetative through partition, and occasionally you can see specimens with only three long arms after the separation of the body disc. However, the opposite side, with three short arms, is just regenerating. Since there are always three long arms, it is conceivable that only six-armed specimens divide. Ophiocoma pumila hiding between a powerhead and the aquarium wall. Especially the propagation of these small brittle stars makes their aquarium care fascinating. And as seen in the previous article, the normally hidden brittle stars can occasionally be observed en masse during spawning. References Addadi, L., J. Aizenberg, A. Tkachenko, S. Weiner, & G. Hendler. 2001. Brittlestar optics: Calcitic microlenses as part of the photoreceptor system. Nature 412: 819–822. Knop. D. (in press): Lexikon der Meeresaquaristik. Natur und Tier Verlag, Münster, Germany.

Can unusual suspects reform the aquarium livestock trade?

CORAL Senior Editor Ret Talbot, lead author of THE BANGGAI CARDINALFISH, coming soon from the Banggai Rescue Project. Opinion By Ret Talbot Excerpt from CORAL, May/June 2013 I was having a conversation last night with a person who knows his way around the marine aquarium livestock trade and hobby. We were discussing the future of both trade and hobby in light of the increasing number of potential restrictions to keeping fishes and other marine animals. Any of these—the current NOAA proposal to list 66 species of coral under the Endangered Species Act or the Invasive Fish and Wildlife Prevention Act, recently reintroduced in the U.S. Congress, for example—could end the aquarium trade as we know it. So could recent, well-funded efforts by, amongst others, the Environmental Defense Fund and the Defenders of Wildlife. I suppose the stunned outrage and anger with which some aquarists have responded to these threats—real and perceived—on social media and in online forums is understandable, but should we really be stunned or outraged? Collection live aquarium fishes with cyanide, a practice still rampant in the Philippines and Indonesia, according to many observers. Image by Lynn Funkhauser, from The Conscientious Marine Aquarist. While there are plenty of solid arguments against many of the anti-trade initiatives that seem to keep popping up like Xenia in a reef tank, the fact of the matter is that aquarists may well be better served by focusing our efforts inward on the aquarium livestock trade itself. Stunned or dead or dying reef fishes after exposure to cyanide. Image by Lynn Funkhauser, from The Conscientious Marine Aquarist. After all, the trade has made itself a viable target for anti-trade activists. Let us not forget recent import data shows the aquarium trade still depends primarily on countries where destructive and illegal fishing techniques are the norm rather than the exception (think cyanide use in Indonesia and the Philippines). Let us not forget that smuggling of species remains commonplace (think illegal wild Banggai Cardinalfish exported from Indonesia or Clipperton Angelfish coming into California). Let us not forget that carelessness and ignorance have led to invasive species introductions that have had significant ecosystem impacts (think Volitans Lionfish in the Caribbean and Caulerpa introductions in Europe and the U.S.). Many important voices have advocated for trade reform over the past two decades, and many positive steps have been taken in the right direction. Nonetheless, none of these efforts have resulted in the type of systemic change required to remove—or at least reduce in size—the bullseye from the back of the aquarium trade. Why is this? Does the trade lack the will? The resources? The imagination? The incentive? Whatever the reason, as my colleague with whom I was having this conversation pointed out, “The same approaches from the same people haven’t worked in 20 years.” Maybe it’s time to look to some unusual suspects as the drivers of change. Game Changers? An important paper was published about a year ago in the journal Zoo Biology that suggests a new group of players may be the ones to effect real change in the aquarium trade. Titled “Opportunities for Public Aquariums to Increase the Sustainability of the Aquatic Animal Trade” (Tlusty et al., 2012), the paper contains an intrinsic premise: the aquatic animal trade is currently deficient when it comes to sustainability. More important, however, the paper points out that it doesn’t have to be, and public aquariums have an opportunity to play an important leadership role in transforming the trade from a threat to a positive force for aquatic conservation. While there are other entities that also have the opportunity to play a significant role in reforming trade, I’d like to take a moment here to explore the potential role of public aquariums. Aquatic tunnel at the Georgia Aquarium, Atlanta: Can public aquariums, using some of the same sources that supply animals to the marine aquarium hobby, help lead the way toward a more sustainable livestock trade? Image: Sean Pavone Photo/Shutterstock. Public aquariums have always had an uneasy relationship with the aquarium hobby. While many curators at public aquariums are home aquarists themselves—and although many of the researchers on staff will credit their passion for all things aquatic to keeping a fish tank as a kid—the overall institutional sentiment has too often been “it’s probably best if you leave it to the professionals.” After all, the aquarium hobby and the trade that supplies it with animals have been responsible for all manner of all-too-public mishaps and missteps that make the institutions—the professionals—want to distance themselves from the “hobbyists.” Gone, some say, are the glory days of late-nineteenth-century amateur scientists seriously engaged with professional scientists in the parlors and conservatories of Victorian homes. As the Zoo Biology paper shows, public aquariums, however, cannot quite so easily distance themselves from home aquarists and the aquarium trade that supplies both with live animals. Public aquariums have a complex relationship with home aquarists and the livestock trade whether they want to acknowledge it or not. The reality is that aquarists visit public aquariums in significant numbers, and visitors to public aquariums are more likely to begin keeping fishes and other aquatic organisms at home than the general public. Put another way, the authors of the paper present data showing public aquariums make new home aquarists. In addition, public aquariums often rely on the same trade networks of collectors and importers as do home aquarists. While some public aquariums mount their own collecting expeditions, almost all rely to a greater or lesser extent on the same importers who supply the animals in our home aquariums. The necessary conclusion of this analysis is that, if the aquarium trade is deficient when it comes to sustainability, then public aquariums are complicit in that deficiency. To be fair, this complicity is offset at the best public aquariums through messaging about conservation and educational initiatives, but the fundamental truth remains that as long as the aquarium trade exists, public aquariums, either directly or indirectly, will play a significant role in supporting that trade by creating new home aquarists, encouraging existing aquarists, and directly acquiring animals through established trade networks. It follows that public aquariums, given this overlap with the aquarium trade, should increasingly be incentivized to take an active role in effecting trade reform, and this should be very good news for the home aquarist. Not Reinventing the Wheel Public aquariums, unlike many of the people and organizations that have attempted trade reform over the past two decades, have resources and expertise giving them a very good chance of actually effecting positive systemic change. Unlike the “same approaches from the same people,” public aquariums are in a unique position to improve the sustainability ethos in the trade. Take, for example, the role public aquariums have adopted when it comes to sustainable seafood (and let’s recall that the seafood trade didn’t make a move until that trade was threatened). In a little over a decade, some public aquariums (such as Monterey Bay Aquarium and New England Aquarium) have, in essence, become non-governmental environmental organizations that have played a leading role in promoting sustainable fisheries and environmental stewardship. They have provided invaluable technical knowledge to the seafood industry through their own research initiatives. They have launched educational initiatives within their institutions that have put the topic of sustainable seafood on the front page and above the fold, and they have taken that message to the general public through a bevy of outreach programs. What if public aquariums did the same for the aquarium trade? As the Zoo Biology paper points out, “…given that public aquariums exist to exhibit aquatic organisms for educational purposes, it is ironic that fish species destined for the plate currently have more sustainability efforts directed at them than do live fishes kept by private aquarists and public aquariums.” Is it too much to argue that the seafood industry’s past could be the aquarium trade’s future? There are many other strengths beyond public aquariums’ engagement in sustainable seafood that could easily be applied to promoting a sustainable marine aquarium trade. Public aquariums, for example, are already educational leaders and have become trusted sources for important conservation messaging on a whole host of environmental concerns from global climate change to conservation of habitat. Think of the ways public aquariums could leverage this educational strength toward developing and teaching best practices for the aquarium trade and informing the public about the risks and benefits associated with aquarium keeping. Through already established social pathways, public aquariums are in a unique position to help educate aquarists about sustainable options for purchasing fishes and other aquatic organisms, and they can be instrumental in creating market-based initiatives linking sustainable aquarium fisheries to retail outlets. Despite government regulations, illegal poaching and uninspected exports of the Banggai Cardinalfish from Indonesia place severe pressures on a species listed as Endangered by the IUCN. Image by Matthew Wittenrich for the Banggai Rescue Project. As respected leaders in sustainability and conservation, public aquariums can accomplish a lot simply by actively supporting sustainable (or, in some cases, withdrawing support from unsustainable) initiatives in the trade. Whether these are specific fisheries, trade routes, wholesalers, or retailers, the support of public aquariums can give credence and bring attention to those elements of the trade that are “doing it right.” Conversely, as trusted thought leaders, public aquariums can marginalize those elements of the trade that are not achieving or at least moving toward sustainability. Likewise, staff researchers at public aquariums are in a unique position to provide much-needed impartial oversight and data analysis of the trade, which may lead to important public-private partnerships including, but not limited to, serving in an advisory capacity to the trade and participating in multi-stakeholder processes toward developing best practices. Of course there are many other areas in which public aquariums can engage the trade in an effort to promote sustainability. Perhaps the most public of these has been the role public aquariums have played in valuable research that can have a direct impact on the trade. For example, through the well-known Rising Tide Initiative and similar programs rearing fishes from eggs collected at public aquariums, public aquariums are playing an active role in closing the life cycle on the captive culture of more species of marine fishes. Increasing the number of captive-bred fishes available to home aquarists—especially beginning aquarists—is a critical effort when it comes to sustainability.  This is, however, a double-edged sword, as too often captive-bred animals are held up as the gold standard of a sustainable aquarium trade. The much more complex story—and one public aquariums are well positioned to tell—is that continuing to support sustainable wild fisheries in addition to increasing captive breeding can provide invaluable economic incentive to conserve aquatic ecosystems. Is it a mandate for public aquariums to reform an aquarium trade that is viewed by many as a threat to aquatic conservation? Of course not, but as the Zoo Biology paper makes clear, public aquariums do have an opportunity here, and engaging in that opportunity does make good sense from an economic and environmental standpoint. While it may not be public aquariums’ responsibility to reform the trade, it should be acknowledged that their failure to act would perpetuate the status quo and potentially even allow the situation to become worse. Conversely, an approach similar to that which aquariums took with seafood a decade ago has the power to effect real change and empower a consumer-driven conservation initiative that will benefit species, habitat, and people. Sea Change Kelp Forest exhibit at the Monterey Bay Aquarium. Image: Sky Collins/Shutterstock. As my colleague remarked last night, “The same approaches from the same people haven’t worked in 20 years.” What has worked, however, are anti-trade activists’ campaigns to end the marine aquarium trade (consider the mounting efforts to ban livestock collection in Hawaii). Isn’t it time aquarists stopped adopting the victim mentality in the face of these threats to the aquarium hobby? Isn’t it time aquarists supported real and substantive reform? Before criticizing those who are criticizing the trade, aquarists would be wise to do some introspection and decide on which side of history they want the trade to fall. Will the aquarium trade and hobby be viewed as a force for good? Will aquarists be seen as standing in the trenches on the front line of ocean conservation? Or will the aquarium trade be seen as little more than wildlife trafficking with a “get it while you can” mentality? As someone who has covered sustainability issues in the aquarium trade for several years now, I believe the necessary trade reform is going to be driven by some new players—entities that have the incentive, resources, and imagination to achieve what others have been unable or unwilling to achieve. As discussed above, public aquariums and, by extension, the American Association of Zoos and Aquariums (AZA) and the World Association of Zoos and Aquariums (WAZA) will play a leading role in positive reform, but so will others. Home aquarists and many in the trade have not traditionally embraced many of these “new” players. In fact, some would be hard pressed to even identify them as players, but their efforts and engagement in the issues that will make or break the aquarium trade have already proven they are the ones with the incentive, the resources, and the will to make a change. Expect, along with public aquariums, to see the Petcos and Disneys and Sea Worlds of the world define the agenda in the coming months. Expect the Pet Industry Joint Advisory Council (PIJAC) to engage on behalf of, and in conjunction with, these entities. Aquarists and individuals involved with the trade have a choice here—will the likes of public aquariums, Petco, Disney, and Sea World be embraced or shunned? Will aquarists become fractured and segmented over petty arguments about who really knows best and what the best path forward ought to be, or will aquarists support these emerging thought leaders and enter into a constructive dialogue with them? Will those in the trade expand their relationships with these players and actively collaborate to increase the sustainability of the trade, or will they insist on a business-as-usual approach that will only push the trade closer to the abyss? The marine aquarium hobby and livestock trade is at a crossroads. It finds itself at the intersection of outdated models and new approaches, resistance to change and openness to new possibilities. Society is becoming “greener,” and while some of that is no doubt little more than greenwashing, there are real steps being taken toward a more sustainable future. A growing number of consumers are not only familiar with sustainability—they are now demanding it. Corporate responsibility initiatives, often born of enlightened self-interest, are on the rise. The aquarium trade can and should be part of this. What if, for example, we could hold the aquarium livestock trade accountable by walking into the local fish store and knowing which fishes were collected with cyanide in the same way DNA testing can insure accountability for the seafood industry? The aquarium industry is going to change; the only question that remains is who will be responsible for that change. Will it be a change from within, driven by those of us who understand the trade, or will it come from anti-trade activists and Draconian measures levied by those who know little about the real impacts and educational rewards of keeping an aquarium? It’s not difficult to imagine that we are on the brink of an important sea change, and I, for one, embrace this new direction. References Tlusty, M.F., A.L. Rhyne, L. Kaufman, M. Hutchins, G.M. Reid, C, Andrews, P. Boyle, J. Hemdal, F. McGilvray, and S. Dowd. 2013. Opportunities for public aquariums to increase the sustainability of the aquatic animal trade. Zoo Biol 32 (1): 1–12. doi: 10.1002/zoo.21019. Epub 2012 May 1.

CORAL Featured Video: Shane Canellis’ SPS Reef Here’s a very nice SPS reef with thriving corals in a 4x2x2 footprint. (Approximately 120 gallons or 450 L, 120 x 60 x 60 cm.) Interesting sound track is a bonus. Credit: Shane Canellis | YouTube “You can find more info on the tank at Profile ssbk23. ”

Back from the Dead: Remote Reef Recovers

10 Apr, 2013 Coral patch in the Scott Reef area of northwestern Australia, now showing strong recovery from a devastating 1998 bleaching event. Credit: N. Thake. Contrary to popular wisdom, coral reefs in remote areas have the potential to rebound from bleaching events and in time frames that marine biologists find astonishing. Isolated coral reefs can recover from catastrophic damage as effectively as those with nearby undisturbed neighbours, a long-term study by marine biologists from the Australian Institute of Marine Science (AIMS) and the ARC Centre of Excellence for Coral Reef Studies (CoECRS) has shown. Scott Reef, a remote coral system in the Indian Ocean, has largely recovered from a catastrophic mass bleaching event in 1998, according to the study published in the journal Science. Following the bleaching event in 1998, 70-90% of stony corals were killed in the Scott Reef area 300 km off northwest Australia. Credit: L. Smith. The study challenges widely accepted theory that suggested isolated reefs were more vulnerable to disturbance, because they were thought to depend on recolonisation from other reefs. Instead, the scientists found that the isolation of reefs allowed surviving corals to rapidly grow and propagate in the absence of human interference. Australia’s largest oceanic reef system, Scott Reef, is relatively isolated, sitting out in the Indian Ocean some 250 km from the remote coastline of north Western Australia (WA). Prospects for the reef looked gloomy when in 1998 it suffered catastrophic mass bleaching, losing around 80% of its coral cover. The study shows that it took just 12 years to recover. Scott Reef lies 300 km off northwestern Australia and is a group of atolls in the Timor Sea. Credit: Carto ANU Spanning 15 years, data collected and analysed by the researchers shows how after the 1998 mass bleaching the few remaining corals provided low numbers of recruits (new corals) for Scott Reef. On that basis recovery was projected to take decades, yet within 12 years the cover and diversity of corals had recovered to levels similar to those seen pre-bleaching. “The initial projections for Scott Reef were not optimistic,” says Dr James Gilmour from AIMS, the lead author on the publication, “because, unlike reefs on the Great Barrier Reef, there were few if any reefs nearby capable of supplying new recruits to replenish the lost corals at Scott Reef. “However, the few small corals that did settle at Scott Reef had excellent rates of survival and growth, whereas on many nearshore reefs high levels of algae and sediment, and poor water quality will often suppress this recovery. “We know from other studies that the resilience of reefs can be improved by addressing human pressures such as water quality and overfishing,” says Dr Gilmour. “So it is likely that a key factor in the rapid recovery at Scott Reef was the high water clarity and quality in this remote and offshore location.” Dr Andrew Heyward, Principal Research Scientist at AIMS, highlights another conclusion from their findings. “Previously we’ve tended to factor proximity to other reefs as a key attribute when estimating the resilience of a reef following a major disturbance, but our data suggests that given the right conditions, reefs might do much of the recovery by themselves.” This finding could have implications for the management of marine protected areas. In their publication the team also draws attention to the important role played by climate change in the longer-term prospects for coral reefs, as Prof Morgan Pratchett of CoECRS explains. Scott Reef had largely recovered from a catastrophic mass bleaching of corals within twelve years of the disturbance, despite the lack of connectivity to other reefs in the region. The rate of recovery was attributed to the lack of many local anthropogenic pressures affecting reefs around the world, such as degraded water quality and overfishing of herbivores (credit: N Thake). “While it is encouraging to see such clear recovery, we need to be mindful of the fact that the coral recovery at Scott Reef still took over a decade. If, as the climate change trend suggests, we start to see coral bleaching and other related disturbances occurring more frequently, then reefs may experience a ratcheting down effect, never fully recovering before they suffer another major disturbance. “By preventing illegal fishing and enhancing water quality on coral reefs in all regions we will give these reefs a greater capacity to recover from major disturbances.” The highly detailed, long-term data set makes Scott Reef the best studied reef in Australia’s Indian Ocean territory. The study provides valuable new perspectives on ecosystem function and resilience of coral reefs situated in the northwest Australia, and in other contexts such as the Great Barrier Reef, and illustrates the importance of AIMS’ research collaborations with its industry partners. CREDIT: From materials released by the Australian Institute of Marine Science, Townsville, Queensland. Images provided by Science in Public. The paper “Recovery of an isolated coral reef system following severe disturbance”, by J. P. Gilmour, L. D. Smith, A. J. Heyward, A. H. Baird and M. S. Pratchett was published by the journal Science on 5th April, 2013. Science 5 April 2013Vol. 340 no. 6128 pp. 69-71DOI: 10.1126/science.1232310 ABSTRACT Coral reef recovery from major disturbance is hypothesized to depend on the arrival of propagules from nearby undisturbed reefs. Therefore, reefs isolated by distance or current patterns are thought to be highly vulnerable to catastrophic disturbance. We found that on an isolated reef system in north Western Australia, coral cover increased from 9% to 44% within 12 years of a coral bleaching event, despite a 94% reduction in larval supply for 6 years after the bleaching. The initial increase in coral cover was the result of high rates of growth and survival of remnant colonies, followed by a rapid increase in juvenile recruitment as colonies matured. We show that isolated reefs can recover from major disturbance, and that the benefits of their isolation from chronic anthropogenic pressures can outweigh the costs of limited connectivity. EDITOR’S SUMMARY Reef Repair Coral reefs suffer mass mortality because of coral bleaching, disease, and tropical storms, but we know much more about when, where, and how rapidly these ecosystems have collapsed than we do about their recovery. Gilmour et al. (p. 69; see the Perspective by Polidoro and Carpenter) studied a highly isolated coral reef before and after a climate-induced mass mortality event that killed 70 to 90% of the reef corals. The initial recovery of coral cover involved growth and survival of remnant colonies, which was followed by increases in larval recruitment. Thus, in the absence of chronic disturbance, even isolated reefs can recover from catastrophic disturbance.;jsessionid=BDA4BF70AA0D7EAAAAB8D8F60F53D680