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Global Reef Expedition: Canopies of Coral

by | Jun 24, 2013 | Conservation, Corals, Fish, Travel

Fiji’s Moala coral gardens, June 2013. Image by Dr. Andy Bruckner, Global Reef Expedition. By Andrew Bruckner, Ph.D. Global Reef Expedition Fiji’s reefs house some 333 species of corals of all shapes, sizes and colors, many of which we’ve seen in Lau Province.  We’ve examined many reef types, some which fringe the shore (fringing reefs), some in the center of a lagoon (lagoonal patch reefs), and some that form a barrier between the open ocean and the lagoon (barrier reefs).  We’ve also surveyed different habitats within these reefs – the reef flat, reef crest, pinnacles and coral bommies, fore reef slope and lagoonal floor, from about 30 meters (m) depth to just below the water’s surface. Unusual pigmentation in a Leptoseris sp. colony in Fiji. Image by Dr. Andy Bruckner. For each survey, we record the type of coral, how much of the bottom is covered by each coral, the sizes of the corals, and their health, within a defined area (10 m belt transect).   What’s remarkable is how vastly different the reefs are on each island and sometimes between reefs within an island.  After nine islands, we continue to add new corals to our species list and often come up from a dive in awe of what we’ve witnessed. Some species, such as the magnificent bubble coral (Plerogyra sinuosa), whose surface covered in translucent grape-like bubbles by day and elongate, deadly tentacles by night (well, not to a human, but extremely painful if you accidentally run into them), we’ve seen just once.  Other corals, such as the large table-forming corals in the genus Acropora (acroporids) are found everywhere.  They often form multiple canopy layers, towering above other corals and covering much of the bottom.  Nevertheless, these tables (and other acroporids such as the staghorn corals) consist of more than 150 different species, each with different patterns of branching, different skeletal structures, and highly variable coloration. Huge Merulina sp. colony in Fiji. Image by Dr. Andy Bruckner. The state of the corals also varies from one reef to the next. We’ve seen reefs with nearly 100% of the bottom covered by coral and others with few corals.  Also, the size of individual colonies can vary from just a few centimeters to over 5 m (e.g. Diploastrea).  Because we have no way of knowing the exact age of a coral, we measure their sizes – this is a proxy for age which provides useful information on the past history and possibly future trajectories of a coral reef. For instance a reef with only small corals is likely to have been severely damaged but is recovering, whereas a reef with only large corals may have had a long history without disturbance.  An assessment of coral condition (e.g. health) provides further information necessary to understand possible causes of damage or threats, and can help predict the future fate of that reef.  So how healthy are the corals of Lau Province?  Check back tomorrow to find out. CREDIT Visit the Global Reef Expedition Site to sign up for frequent updates directly from the science team. Science Without Borders® is the overarching theme of the Khaled bin Sultan Living Oceans Foundation. Its purposes are to provide financial sponsorship of marine conservation programs and scientific research, and to promote public awareness of the need to preserve, protect and restore the world’s oceans and aquatic resources.

ReefGen Coral at Live Aquaria’s Divers Den

by | Jun 19, 2013 | Corals

ReefGen is excited to work with Live Aquaria to provide hobbyists with high quality captive grown coral. These corals are now available in Live Aquaria’s Diver’s Den. Some of the mother colonies for ReefGen Coral are housed in Joe Yaiullo’s groundbreaking 20,000...

Arrested by the Tang Police: I Refuse to Confess!

by | Jun 17, 2013 | Corals, Fish, Opinion, Science, Tanks

The Poster Child of the Tang Police: Paracanthurus hepatus is actually very site-specific and not range as widely over the reef as do other tang species. By: C.M. Schwimm* Most marine aquarists who frequent online message boards have heard the term “Tang Police” (abbreviated here as TP). Some are even members of this group themselves, while a few other unlucky souls have been “arrested” by them. Conversely, there are also a few people willing to challenge their assertions regarding the swimming space requirements of Acanthurids (surgeonfishes and tangs). For those who haven’t heard the term, it will help to define the phrase “Tang Police.” The best way to identify an officer in this force is by hearing him LOUDLY express his opinions regarding the amount of swimming space required by tangs (or other species). The author, anonymous but well known to the Tang Police. In most cases, there is the lack of finesse in the approach of these vigilantes. The TP often participate in a pile-on where an unsuspecting beginning aquarist asks about buying a Pacific Blue/Hepatus Tang for their 29-gallon tank. Multiple rude, curt and insulting responses are common, and the OP (original poster) often slinks away, very embarrassed. Now, it is important to note that nobody ever admits to being a member of the TP. The term is actually considered insulting, so nobody wears it as a badge of honor. One forum moderator explains it thusly: “… the higher ups here at [Forum Name withheld] (and not on a whim) have decided that it [the term Tang Police] is an insult, one that shouldn’t be said.” Feeling Like a Tang Although the individual enforcers usually won’t admit to being TP members, and a forum I have often frequented has forbidden the use of the term, people will still make statements such as this: “I just care about tangs, so if that makes me a member in your eyes, then so be it.” This is an important point. A person has every right to an opinion about how much space a tang needs, but if they don’t get in your face about it, they are not a member of the TP. Another common trait is anthropomorphizing of the issue – a TP deputy will often be heard saying things along these lines: “that tang cannot be happy in that size aquarium” or “how would you like it if you were locked into a 10-foot-by-10-foot room your whole life?” One interesting feature common to most of these opinions is the preference for giving tangs huge amounts of aquarium space, yet almost universally ignoring the swimming needs of other very active fishes such as large wrasses, fusilers, and parrotfishes. Enter the Professional Aquarist So what size tank do police members advocate for tangs? The tongue-in-cheek answer is: 50% larger than the tank you have, or they wouldn’t be confronting you about it in the first place. In reality, the message board most often patrolled by the TP does have a set of guidelines, based on personal opinions, which they loosely follow. As an experienced professional aquarist, my minimum tank sizes run about 25% smaller than those they advocate for. This is a relatively small difference, except for Paracanthurus hepatus where they suggest a minimum aquarium size of 240 gallons and eight-feet long. This is wholly unrealistic and puts most home aquarists housing this species in jeopardy of being thrown in jail by the TP. My own research shows that the minimum tank size for an adult Hepatus Tang (typical captive adult size of 11 inches) is on the order of 24 inches by 65 inches of open water space, or about that found in a typical a 150-gallon aquarium. This Neon Fusilier, Pterocaesio tile, is an open-water swimmer that needs more room than any tang, yet the Tang Police never seem concerned about it and other wide-ranging species and genera. Science-based Guidelines Here are some considerations regarding any claims as to the amount of swimming room that a fish needs in captivity: 1) If somebody tells you for example, that a 6” fish needs a 100-gallon aquarium— that is wrong from the start. This is like saying your car gets 500 pounds to the mile. There is no way this can ever work unless you are speaking of one specific size of a fish in one size aquarium. The example I always use is that you can put 10 two-inch Green Chromis in a 50-gallon aquarium, but try to put one 20-inch grouper in there! The total inches of fish are the same, but the fish’s VOLUME goes up exponentially as the length increases in a linear fashion. Now, what DOES work is to compare the length of the fish to the open water area of the tank (length plus width). Put this into a ratio to facilitate comparisons between tanks. For example, a 4-inch angelfish in an aquarium that has an open water length of 40” and an open water width of 12” would result in a ratio of which reduces to 1:13, an adequate minimum amount of space. 2) Comparing apples to oranges is very common in these discussions. If you tell me that you want to put a six-inch long tang in a 100-gallon aquarium, I have a mind’s eye view of an open-water swimming area (length plus width) of around 80 inches. | This is because a public aquarium administrator, I automatically just deduct 15 percent from the gross dimensions of any aquarium for “decorations.” A reef aquarist has a much different view of a 100-gallon aquarium (usually filled with live rock and corals). Their thought is that this aquarium has only perhaps 50-inches of open swimming room. No wonder there is a lack of agreement in some cases. So— the first step is to just work with open water area, and forget the actual gross volume of the aquarium altogether. 3) People are really, really bad at estimating the size of fish in aquariums. I performed a survey 25 years ago, in which I polled volunteers and staff at a public aquarium regarding how large they thought fish in the exhibits were. The aquarium staff did a pretty good job of estimating the size of the fish (taking into account magnification of the water, etc.) while the volunteers were all over the board, with a range of around plus or minus 80 percent. The thought here is that some people may write “six-inch tang,” but if you actually took the fish out of the water and measured it, the length might only be five inches. 4) Frequently, the FishBase web site (www.fishbase.org) is used to identify the maximum size that a fish will reach. The Tang Police then use this measurement and their opinion as to swimming room needs, to determine a suitable aquarium size. The problem is that the FishBase information is for the maximum recorded size of an adult fish. This is larger than the normal adult size for that species. In addition, some tangs are sexually dimorphic, with “supermales” growing much larger than normal. This is not seen in captivity. Finally, captive fish do not grow as large as they do in the wild. In one study that I made, a group of adult, public aquarium fish had reached on average, only 66 percent of the maximum FishBase length. To be a bit conservative, it is probably best to use 80 percent of the maximum FishBase length as the size to which the fish will grow in an aquarium. 5) It is inherently easier to add any “buffer” to an aquarium size requirement. You cannot be proved wrong if you select a tank size that is larger than a fish really needs. The question though, is what is the minimum suitable tank size for a given species of fish? If a fish shows no artifact of captivity, (bruised snout, bent fins, shortened lifespan, etc.) then you are meeting their minimum requirements. It is often stated that the justification for giving a tang say, an eight-foot long tank is that this is more like what the fish would experience on a reef. The problem is that the biomass of fish in the ocean is on the order of one clownfish in a 20,000 gallon tank (The CRC Handbook of Chemistry and Physics gives the density of living matter in the oceans as: 15*10-8g/cm3.)—so if you want to keep things on the same order of magnitude, you better not keep ANY fish in your tank. The difference between a 75 and a 150-gallon aquarium is inconsequential compared to the potential amount of swimming room that fish have in the wild. Some species such as this Spotted Unicornfish, Naso brevirostris, have more open-water habits and grow quite large. These DO require large aquariums. 6) As previously noted, the Tang Constabulary will frequently state: “That fish cannot be happy in that size tank”. Now, I hope they don’t mean “happy” as in human emotion, and I’ll assume that they really mean “unstressed.” So – their statement is then, that fish kept in smaller aquariums are more stressed. I spoke with a researcher who has actually measured cortisol (stress hormone) levels in wild and captive parrotfish (Turner et-al 2003). He states that after one week of acclimation, there was no difference in cortisol levels between sub-adult parrotfish housed in 50-gallon aquariums compared to those housed in 150-gallon tanks (Turner 2010, pers. comm.). Additionally, he found “…there was no difference in respective hormone levels between aquarium and field environments.” When confronted with this information, one member of the Tang Police stated that this was “not a valid point because parrotfish are not tangs.” Actually, as experienced aquarists know, parrotfish range more widely over reefs than tangs do, and should therefore be given more swimming room. 7) Tangs are not equal in regards to their swimming needs. Juvenile Acanthurus and Paracanthurus are quite site-specific and do not roam widely across the reef. Zebrasoma are also more attracted to bottom structure. The members of the genus Naso and Prionurus are the true open water swimmers; they are the ones that require special consideration. Remember also that tangs are browsers, and swim widely in order to locate sufficient food. This does not equate to their wanting to do this. Many wide-ranging fish are content to reside in one small area as long as there is a good food supply (as evidenced by pelagic whale sharks congregating in small areas where the density of plankton is high). 8) Everything else in aquarium husbandry is closely measured – temperature, water quality, medication doses, etc. I’ve never been able to understand why some people just toss that all out and say, “A fish needs this size tank because that is what feels right to me.” Sensible Metrics They are working backwards to the answer of swimming space requirements. They subjectively start with what they believe to be an appropriate amount of space and then try to develop criteria to support that. I prefer to first identify objective metrics, and then develop suitable aquarium sizes from that. My minimum metrics for captive fishes are as follows: If the fish shows no signs of chronic disease or abnormality, exhibits normal feeding and reproductive behaviors and most importantly, exhibits a normal lifespan compared to that of wild counterparts (minus the predation that wild fish incur of course!), then there is no other metric we can use to determine if a certain suite of husbandry techniques are suitable or not. So – if you have read this far, the topic must be of particular interest to you. Hopefully you don’t think that I advocate keeping fish in overly-small aquariums, as I do not. I always strive to give my captive fish the best possible environment. The exhibits I use for tangs at the public aquarium where I work range from 450 to 1,300 gallons. What I am advocating for here is a more civil discourse, more careful consideration of measurable husbandry parameters, and less reliance on subjective personal opinion. Police or Gestapo? So here is the outcome of my recently being arrested by the “Tang Police” one final time, two years after my first run-in with them. I made a joke at one administrator’s expense (after he made a hugely subjective and derogative comment regarding the aquarium decision-making ability of another person). This was not a smart move on my part – he quickly brought in another forum moderator who deleted my avatar (that had been used there for over four years), they deleted messages in which I linked to outside resources, and ultimately deleted my signature line (which was a legal disclaimer regarding any opinions expressed are mine alone). Of course, I tried to change things back and this resulted in my having so many permanent infractions that I was just about to be Banned for Life. I left that particular message board for another one where the Tang Police are not given so much support. The ironic thing was that of my nearly 2,000 posts there made over 10 years, the vast majority were informational—frequently offering unique information to people having fish disease issues. So I was actually a net gain of information for their community, despite my few run-ins with the Tang Police. ______________________________________________ Reference: Turner, J.W. Jr., Nemeth, R., Rogers, C. 2003. Measurement of fecal glucocorticoids in parrotfish to assess stress. General and Comparative Endocrinology 133 (2003) 341-352 Author’s Note * C.M. Schwimm is a nom de plume, used for professional reasons. The Police will know who I am. The views expressed in this article are mine alone and do not necessarily reflect the views of my employer or the editors of this magazine.

The Unique Corals Supernova Scolymia is Absolutely Out of This World

by | Jun 14, 2013 | Corals, Eye Candy, Industry, Photography

To say that we have an obsession with those big, beautiful Scolymia australis corals is a bit of an understatement. We just can’t get enough of them, whether its watching videos of them inhaling various food items or just gazing at vivid pictures. In our constant perusal of Scoly web content, we always randomly find one or two that put all of the others to shame, but this latest beauty from Unique Corals has really raised the bar for this coral species altogether. Appropriately dubbed the Supernova Scolymia, this amazing piece has out of this world coloration. In fact, it is the best coloration of any Scoly that we’ve laid eyes on, even surpassing the beauty of those legendary ‘Master Scolys’. The 2.5″ WYSIWYG specimen is currently listed at $498, but we don’t expect it to stay on the Unique Corals site much longer, assuming it is still there when this article publishes.