Harlequinmania

Two new studies have shown that the coexistence of tuna larvae of different species and sizes in the spawning areas is essential for the survival of such early life stages, since cannibalism can constitute a significant fraction of natural mortality during this period. View the full article

Two new studies have shown that the coexistence of tuna larvae of different species and sizes in the spawning areas is essential for the survival of such early life stages, since cannibalism can constitute a significant fraction of natural mortality during this period. View the full article

Click through to see the images. Imagine being able to wrap circulation pumps, heaters, and returns and make them invisble in your display tank! Published October 3 in Nanotechnology, researchers have found a way to use carbon nanotube aerogel sheets to create the illusion of invisibility. In essence this nanotube sheet creates a "mirage effect" underwater similar to the heat waves that you see on a hot, sunny day radiating off a paved road. The catch is that it only works underwater and is demonstrated in the below video. The researchers conclude that "the remarkable performance of nanotube sheets suggests possible applications as photo-deflectors and for switchable invisibility cloaks, and provides useful insights into their use as thermoacoustic projectors and sonar." (via io9) View the full article

Click through to see the images. Despite great successes at marine reserves and no-take zones in places like Cabo Pulmo and Hawaii, the Glover's Reef Marine Reserve saw no improvement in herbivorous fish populations and an unexpected decline in corals over the past 10 years of protection. Researchers did not attribute reasons in their study for this troubling finding, only concluding that "reserves that are not designed and implemented specifically for the protection of the coral community may fail to provide benefits to these species." Advanced Aquarist would like to note less than 5% of Glover's Reef is subject to no-fishing zones (mostly seasonal, with only a few areas permanently closed to fishing), so a refinement and/or expansion of the management system certainly has potential to create positive results. Many reefs around the world have dramatically benefited from carefully implemented conservatory management, so these findings should in no way detract from the importance of enforcing more no-take zones to help restore stressed reef communities. Press Release MIAMI — The ability of marine reserves to replenish fish stocks has been studied extensively, but evidence of their ability to benefit shallow-water communities to thrive remains a mystery. A team of scientists from the University of Miami (UM) Rosenstiel School of Marine & Atmospheric Science recently tested whether 10 years of reserve designation has translated into positive impacts on coral communities in Glover’s Reef Marine Reserve, Belize. Results from their surveys of 87 patch reefs both inside and outside the marine reserve showed no clear indication of reserve implementation benefitting coral cover, colony size or the abundance of juvenile corals. The study, conducted by Brittany Huntington, Mandy Karnauskas and UM Professor Diego Lirman appears in the journal Coral Reefs. “We had hoped to find evidence of reserve protection benefitting the coral community as well as the fish community at Glover’s Atoll. Unfortunately, the coral communities on protected reefs were in no better condition than the fished reefs,” says Huntington. Rather, the scientists documented declines in the coral community both inside and outside of the marine reserve. These patterns of coral decline at Glover’s Reef, including a shift in dominance from massive reef-building broadcasting species to smaller brooding species, and low numbers of juvenile corals were documented and seem reflective of regional patterns of coral decline in the Caribbean. The scientists detected no difference in herbivorous fish abundances or the abundance of macroalgae dominating the reef between reserve and fished sites. This provides a potential explanation for the lack of cascading effects on the coral community. “The macroalgae is faster growing than corals, dominating the available free space on the reef and impeding coral growth and survival,” said Huntington. “Without greater numbers of herbivorous fishes in the reserve to consume the macroalgae that is dominating these reefs, corals have little chance at recovery.” The UM team also found that massive broadcasting coral species exhibited greater losses over time than their smaller-sized counterparts, suggesting that local management actions have not alleviated the trend of high mortality for these species. “Glover’s Marine Reserve provides a unique opportunity to learn more about how marine reserves impact coral and fish populations,” says Karnauskas. “Reserves that are not designed and implemented specifically for the protection of the coral community may fail to provide benefits to these species.” About the University of Miami’s Rosenstiel School The University of Miami is the largest private research institution in the southeastern United States. The University’s mission is to provide quality education, attract and retain outstanding students, support the faculty and their research, and build an endowment for University initiatives. Founded in the 1940’s, the Rosenstiel School of Marine & Atmospheric Science has grown into one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. For more information, please visit www.rsmas.miami.edu View the full article

My bottom bracing helps to prevent the rock slipping and touch the glass, so at some point it is good to have those as well especially if you not using any sandbed like me to hold the rocks in place.

Click through to see the images. While visiting the House of Fins' SPLASH event this past weekend in Greenwich, I couldn't help but to stop and check out the display of colorful art created by Karen Talbot. Displayed were several drawings and paintings of clownfish, angelfish, starfish and many other marine organisms. After speaking with Karen, I quickly learned that her art is inspired by what she experiences when diving as well as the importance of conservation in our oceans. Her work includes watercolor, pen & ink and acrylic and Karen explained that she examines these fish in great detail which really helps to create detail and realism in her work. Pictured above is a myriad of information she assembled which explains detail regarding the anatomy of the fish as well as some interesting information about its habitat. If your looking for some high quality reef-related art, be sure to check out the Karen Talbot Art website where you can learn more about her work and even purchase prints and original artwork. Here is Karen herself, explaining the insightful process behind her artwork. View the full article

A gene responsible for aggressive and bold behavior has been identified in zebrafish. This specific behavioral association, whose three characteristics are boldness, exploratory behavior and aggressiveness, has been described in many animal species. In zebrafish, it could be due to the action of a single gene (fgfr-1) through its regulation of histamine levels in the brain, as histamine is the neurotransmitter involved in numerous behavioral traits. View the full article

Researchers have discovered a rare mollusc in Antarctic waters that looks the same as limpets but is bigger in size than the species known to date. The specimen appeared in waters much further away from where this type of species is normally found. View the full article

Click through to see the images. Activists in Hawaii are once again trying to shut down the aquarium fishery industry in its local waters. Earlier this year, Hawaii Senate Bill HB580 sought to prohibit the collecting and selling of aquatic life for aquariums, but has since been amended to become an entirely different bill (with the purpose of establishing new marine reserves). There is now a new attempt to target the aquarium fishery industry. According to a new article by Ret Talbot for Coral Magazine: On Wednesday, 5 October, a resolution to ban the aquarium trade in Hawai’i will be up for discussion at the Hawai’i County Council meeting on the island of Hawai’i (the Big Island). We encourage you to read the article in its entirety, which does an excellent job covering the opposing opinions and providing background on fishery management in Hawaii. The one thing Advanced Aquarist would like to point out is that resolutions are, in essence, teethless. Unlike the real threat of a bill (such as HB580), resolutions are more symbolic than legislative and do not have force of law. Still, seeing this issue crop up again so quickly after the failure of HB580 caught us by surprise. If nothing else, the anti-trade propaganda gives our hobby bad press through demagoguery when the focus really should be on effective fishery management. As the Department of Aquatic Resources' recent report indicates, yellow tang populations are on the rise despite more specimens being collected than ever before. Why? Because of smart fishery management. View the full article

Click through to see the images. Event information: Drygood and Product Vendor Displays & Sales Livestock Vendor Displays & Sales Trick or Treating at all Vendor Booths Professional Aquaria Guest Speakers Haunted Displays Touch Tanks Raffles & Giveaways! Costume Party on Sunday! So Much More… Sanjay Joshi Tony Vargas This is an event you don't want to miss! View the full article

Many different types of animals come together to form vast groups -- insect swarms, mammal herds, or bird flocks, for example. Researchers in France added another example to the list: the huge Wels catfish, the world's third largest and Europe's largest freshwater fish. View the full article

Research sometimes means looking for one thing and finding another. Such was the case when biology professor Alice Gibb and her research team at Northern Arizona University witnessed a small amphibious fish, the mangrove rivulus, jump with apparent skill and purpose out of a small net and back into the water. This was no random flop, like you might see from a trout that's just been landed. The rivulus seemed to know what it was doing. View the full article

Click through to see the images. The 28 recognized species of clownfish (Subfamily Amphiprioninae) share a considerable number of highly recognizable physical and behavioral attributes. That notwithstanding, they may be divided into basic groups to reflect (presumably on the basis of lineage) certain distinguishing characteristics. These six assemblages, or complexes, include the Maroons, the Percula Complex, the Saddleback Complex, the Tomato Complex, the Skunk Complex, and the Clarkii Complex. The largest of these groups, the Clarkii Complex, was discussed in a previous article; this piece examines aspects of the next largest group, the Skunk Complex. The Skunk Complex gets its name from its "type" species, the skunk clownfishes; the common name of the three skunk clownfish species (namely A. akallopisos, A. perideraion, and A. sandaracinos) is derived from the distinctive long, white stripe that runs down the length of their backs. While the dorsal stripe certainly sets these fishes apart from members of the other five complexes in the subfamily, this complex bears numerous distinctions that will be notable to many discerning marine aquarists. Members of the Skunk Complex are, overall, the smallest representatives (in physical size) of the subfamily. Skunk clownfish are not particularly difficult to maintain in captivity; however, at least compared to certain other familiar clownfish species, they can be quite timid, and so should be afforded with appropriate tankmates and aquascapes. Skunk clownfish should be among the first inhabitants to be stocked into an aquarium. Their living space should include plentiful hiding spots. Brutish or predatory fish species should be excluded as potential cohabitants altogether. The Skunk Complex is particularly interesting in that two of its members (Amphiprion leucokranos and Amphiprion thiellei) might not actually be legitimate species by conventional classification guidelines, but rather intrageneric hybrids; this issue may be resolved by further field investigation and genetic analysis. The Skunk Complex in profile Skunk clownfish (Amphiprion akallopisos Bleeker, 1853) The skunk clownfish inhabits shallow inshore reefs throughout the Indo-Pacific Ocean (tropical), often in rather strong currents. It is typically associated with the sea anemone species Heteractis magnifica and Stichodactyla mertensii. It is distinguishable by its rich orange base color, a white tail, an absence of head stripes, and a single, narrow white stripe that runs (starting behind the mouth) down the length of its back. Females are larger than males; mating males are larger than non-mating males. It reaches a maximum length of 11 cm. These Amphiprion akallopisos can be distinguished from the closely related Amphiprion sandaracinos by their dorsal stripes, which do not cover their mouths. Photo by Kenneth Wingerter. White-bonnet clownfish (Amphiprion leucokranos Allen, 1973) The white-bonnet clownfish inhabits lagoons and outer reef slopes throughout the Western Central Pacific Ocean from New Britain to Papua New Guinea and the Solomon Islands (tropical). It is typically associated with the sea anemone species Heteractis crispa, Heteractis magnifica, and Stichodactyla mertensii. It usually bears an incomplete head stripe. While it can be obtained in the trade, it is a rarity that commands top prices. Rather smallish, it reaches a maximum length of 9 cm. Maldive (or blackfoot) clownfish (Amphiprion nigripes Regan, 1908) The Maldive clownfish inhabits reef margins in the Western Indian Ocean from the Maldives to Sri Lanka (tropical). It is typically associated with the sea anemone species Heteractis magnifica. The Maldive clownfish is regarded as one of the most sensitive members of the subfamily, and so should be handled/maintained with great care. It is distinguished by a thick head band, an absence of a dorsal stripe, and very dark pelvic and ###### fins. Males are nearly as large as females, which reach a maximum length of 11 cm. A beautiful reef scene graced by a pair of Amphiprion nigripes. Photo by Jan Derk. Though its base color is somewhat variable, Amphiprion nigripes always has a darker ventral area. Photo by Ewa Barska. Juvenile Amphiprion nigripes in grow-out at Sustainable Aquatics. Photo by Kenneth Wingerter. Pink skunk clownfish (Amphiprion perideraion Bleeker, 1855) The pink skunk clownfish can be found across the Western Pacific Ocean (tropical). This adaptable species thrives in a wide range of habitats, including brackish waters, at depths of 1-38 meters. While it is typically associated with the anemone species Heteractis magnifica, it may also occur with Heteractis crispa, Macrodactyla doreensis, and Stichodactyla gigantea. It is distinguished by a pale orange base color, transparent fins, and a thin head stripe. It reaches a maximum length of 10 cm. Amphiprion perideraion is probably the hardiest species in the Skunk Complex. Photo by Nick Hobgood. Species from the Skunk Complex (such as this Amphiprion perideraion) present an appearance that is decidedly different than that of the customary clownfish display. Photo by Joi Ito. Amphiprion perideraion with its preferred host anemone species, Heteractis magnifica. Photo by Nick Hobgood. Members of the Skunk Complex (such as these Amphiprion perideraion) will fare better if provided with an abundance of hiding places. Photo by Kenneth Wingerter. Orange skunk clownfish (Amphiprion sandaracinos Allen, 1972) The orange skunk clownfish inhabits lagoons and outer reefs in the Western Pacific (tropical). It is typically associated with the sea anemone species Heteractis crispa and Stichodactyla mertensii. It is distinguished by a bright orange base color, an orange tail, an absence of head stripes, and a single, wide white stripe that runs (starting on the lips) down the length of its back. It grows to a maximum length of 14 cm. An Amphiprion sandaracinos shares its anemone host with a fellow symbiont. Photo by Nick Hobgood. Amphiprion sandaracinos is easily distinguished from its closest relatives by an orange tail and a stripe that extends over the mouth. Photo by Jenny Huang. Due to their skittish nature, skunk clownfish (such as this Amphiprion sandaracinos) can make for challenging photographic subjects. Photo by Kenneth Wingerter. Thielle's clownfish (Amphiprion thiellei Burgess, 1981) Thielle's clownfish is native to the Western Central Pacific Ocean (tropical). It has been described from a pair of captive specimens that were said to have originated from Cebu, Philippines. The biology of this enigmatic species remains largely unknown. It is distinguished by having a complete head stripe. It is believed to reach a maximum length of only 9 cm. Conclusion Clownfishes of the Skunk Complex offer aquarists a clear diversion from the more the commonly kept members of the subfamily. Their distinctive patterning makes for an attractive variation from the typical clownfish-anemone aquarium display. Their relatively diminutive size makes them a more suitable choice for smaller aquaria. Their relatively peaceful disposition makes them a suitable choice for community aquaria. The commercial availability of these fishes presently ranges, depending upon the species, from high to quite low. However, due to captive breeding, some members of this complex (most notably Amphiprion nigripes) are becoming increasingly obtainable. While they share many characteristics, each species in the Skunk Complex is uniquely interesting and attractive. Thus, it may be worthwhile to develop a basic understanding of how members of this oftentimes overlooked complex are distinguished from one another. References Wilkerson, Joyce D. Clownfishes: A Guide to Their Captive Care, Breeding, & Natural History. Shelburne, VT: Microcosm Ltd., 1998. Fautin, Daphne G. and Gerald Allen. Anemonefishes and Their Host Sea Anemones. Morris Plains, NJ: Tetra Press, 1994. Skomal, Gregory B. Clownfishes in the Aquarium. Neptune City, NJ: T.F.H. Publications, Inc., 2004. http://fishbase.org http://www.sustainableaquatics.com View the full article

This is extracted from the latest issue of the CORAL magazine; http://mobileservices.texterity.com/coral/20110910/?folio=36&article_id=112905&lm=1317749465000#pg39

Click through to see the images. I won’t kid you: a lot of controversy surrounds this show. Many of you thoroughly enjoy the show – the unorthodox builds, the personalities, the variety of animals that are worked with on a day-to-day basis, the drama that takes place amongst the cast. On the other hand, many of you are concerned (and some down-right angry) about how Animal Planet and Acrylic Tank Manufacturers (ATM) portray the hobby – the choice of livestock, stocking levels, species compatibility, the bungling things that take place with customers during the build process, the lack of educational value about the animals that live in our glass boxes. The list goes on and on in both directions. Discussion about the topics raised by the show range far and wide on the Internet. A quick Google search will return more than you ever wanted to know about the show and peoples’ opinions about it. Brett Raymer speaking at this year’s MACNA in Iowa contributed a lot to the discussion as well. Given that Animal Planet has ordered Season 2 of "Tanked," now is an excellent time to let them know how you feel about the show. This is a huge opportunity for our hobby because Animal Planet and ATM can really do a lot for us in the way of educating the public about proper husbandry techniques, aquaculture and breeding practices, sustainability, issues facing the ocean today (like shark finning and the Atlantic lionfish invasion), and the like. Aquanerd blogged about it last week and I also encourage each of you to make yourselves heard at Animal Planet by sending them an email (comments@animalplanet.ca). Season 2 is coming up. Let them know how they can shape the show for the betterment of the hobby. View the full article

Click through to see the images. The Nemo Effect Part II? When Disney released "Finding Nemo" in 2003, the aquarium industry experienced a boom in the sales of saltwater fish despite the movie's underlying message of "reef fish are better left in the sea." Clownfish sales in particular experienced dramatic growth when many moviegoers wanted a little Nemo of their own. This, in turn, provided an economic boost to commercial clownfish breeders like ORA (USA). The sudden growth spurt was not without its perils and criticisms. Most newcomers were ill-equipped (with knowledge, equipment, and commitment) to adequately care for their new saltwater animals because "Finding Nemo's" fan base consisted primarily of small children, with parents appeasing their children's demands. Now a new generation of children will experience "Finding Nemo" for the first time. Are we in for another round of "Nemo effect?" Is this good or bad for our hobby? What can (or should) we do in preparation for the potential surge of new aquarists? Advanced Aquarist sees this as a great opportunity to educate people (especially children) about our hobby, about sustainable/responsible practices, and about the importance and state of the world's coral reefs. For the Disney fans, the schedule for the four upcoming 3D Disney re-releases are: “Beauty and the Beast,” (Jan. 13, 2012) “Finding Nemo” (Sept. 14, 2012) “Monsters, Inc.” (Jan. 18, 2013) “The Little Mermaid” (Sept. 13, 2013). Advanced Aquarist thanks the folks at Marine Depot for the lead. View the full article

I think Madpetz Start to sell them too. I have been using one for Some time now and so far so good.. Surprising..

Africanus only come in from Africa shipment, so if there is a Africa shipment in one of the LFS, most likely you will see this since it is a common fish in Africa. Sealife, irwanna and LCK do bring them in from time to time..

Understanding Led Lighting and its use for reef aquariums by Sanjay Joshi, Ph.D. LED lighting technology for the marine aquarium hobby is constantly being updated and improved. In this article, Professor Joshi explains how LEDs function, assesses their suitability for coral-reef aquaria, and discusses the criteria for selecting an LED aquarium light LEDs (light emitting diodes) are an exciting new technology that has the potential to change the way we light our aquariums. There is considerable interest in LEDs due to a large number of potential advantages: reduced power consumption, extremely long life (which could eliminate changing of bulbs), reduced heat input to the aquarium, selective dimming to simulate dawn/dusk/ tropical cloud cover, wide range of effective color temperatures to satisfy aquarist preferences, and more aesthetically pleasing displays that combine spotlights and uniform lighting. It is this potential for addressing the aquarist's needs with a single lighting system that has generated such enthusiasm for LED lighting technology and its use in the aquarium. As with any new technology, there has been skepticism as to whether it will perform better than, or even as well as, existing technology. Understanding the technology and its implementation, how it functions, what aspects are relevant to reefkeeping, what the potential pitfalls are, and how it compares with existing lighting are all important elements in allaying the fear and skepticism generated by this new and potentially game-changing approach to lighting. WHAT ARE LEDS AND HOW DO THEY WORK? LEDs were first developed in the 1960s, and initially they were used for indicator lights in electronic equipment, traffic lights, electrical signs, and simple displays (calculators, watches, etc.), where the light source is easily seen. The 5-mm LEDs that are commonly available were designed for these applications and have been in use for a long time and in large numbers, resulting in low manufacturing costs and retail prices. LEDs are not really designed for illumination. Illumination requires that the light source provide enough light to permit the viewing of other objects, much like a typical light bulb or fluorescent light. Here the objects are made visible by the reflection of the incident light emanating from the light source. Modern high-output, high-power LEDs, which deliver meaningful levels of light for illumination, started to become commercially available in the late 1990s. Since their introduction there has been steady development in LEDs designed for illumination, focusing on providing the highest output per watt consumed and creating white light, with the ultimate purpose of replacing existing lighting technology for all household and commercial applications. For aquarium purposes, LEDs must not only illuminate but also stimulate and maintain photosynthesis at desired levels. In principle, LEDs are similar to the simple silicon p-n junction diode. Diodes are electrical devices that allow electricity to flow in one direction, similar to a check valve in plumbing. The diode is formed by two slightly different semiconductor materials that create a positive and negative (p-n) junction. On one side of the junction, the p side, there is an excess of positive charges (holes), and the n side has an excess of negatively charged electrons. In a state of equilibrium, the electrons and holes stay on their respective sides, separated by a small “depletion zone” where the holes and electrons have combined and achieved equilibrium. To get the electrons and holes to move toward the junction, energy is supplied in the form of electrical voltage and current by connecting to a power source, such as a battery or DC power supply. The amount of voltage and current required for electroluminescence to occur is called the forward voltage and forward current. When the electrons and holes combine at the junction, the result is a release of energy, which, in an LED, is released as light (radiative recombination) and heat (non-radiative recombination). A simple diagram depicting this process is shown in Figure 1 (previous page). The LED chip is typically packaged into a functional unit. Figure 2 is a photograph of an LED package. Figure 3 shows the typical construction and packaging of a high-output LED. There are several features incorporated into the package design. There is a direct thermal path from the chip to the printed circuit board on which it is mounted. As we will see, heat management is a vital part of high-power LED use. The chip is encapsulated in a polymer/epoxy to increase the extraction efficiency of the light and provide protection against unwanted mechanical shock, humidity, and chemicals. The polymer/epoxy encapsulant also stabilizes the LED chip, bonding wires, and cathode and anode leads. Due to the softness of the polymer encapsulant, it is covered with a plastic cover that also serves as a lens. The chip is mounted on a silicone submount with built-in electrostatic discharge protection. Visible light is the energy released within the 400 to 700 nm wavelength range. While we may refer to light by its color, it is more accurately classified based on the wavelength or energy of the released photons of light. Energy released as photons in the 400 to 450 nm wavelength range appears to us as blue light, while photons at 650 to 700 nm appear as red/orange. The various colors of the rainbow (VIBGYOR) are arranged along the wavelength range from 400 to 700 nm. See Figure 4. The type of semiconducting material used to build the p-n junction determines the color (or the energy distribution of the released photons). Red, yellow, and orange LEDs are produced using aluminum gallium indium phosphide (AlGaInP), and indium gallium nitride (INGaN) alloys are used for green and blue lights. Changes in the composition of the materials used change the color of the light emitted. LEDs typically produce monochromatic light (light of a single predominant color), which means that the light distribution has a narrow spectral width. White light, on the contrary, has a wide spectrum comprising a wide range of colors. Creating white light that matches with human perception is a challenge. White light is produced by LEDs mainly through the use of phosphors activated via short-wavelength light (UV or blue)—in much the same way that fluorescent lights produce light. New phosphors are continually being developed to improve the quality of white light. Another way of making white light is by mixing different-colored LEDs to create a spectrum that appears white. White light can be created by using red, blue, and green LEDs in close proximity to ensure proper mixing of the output. The table at top left compares the different technologies used for white light. Blue LEDs using phosphors are currently used for most aquarium lighting. Figure 5 compares the two phosphorbased white light LEDs to natural sunlight. When reading about white LEDs, you will often encounter the terms luminous efficacy, color temperature, and color-rendition index. Luminous efficacy is the term used to describe the energy efficiency of a white light source—how well it converts the energy input in watts to light output as perceived by the human eye. Luminous efficacy is expressed in lumens/watt (lumens are the unit used to measure how light is perceived by the human eye). Typical incandescent lamps have a luminous efficacy of about 15 lumens/watt. Compact fluorescent and metal halide lights have luminous efficacy ranging from 90-110 lumens/watt. Commercially available LEDs have reached up to 110 lumens/watt, while LEDs in research labs have reached 231 lumens/watt. Higher efficiency is better for users because it reduces energy needs and fewer LEDs are required to achieve the same light levels. Color temperature is the term used to describe the color of the light produced by comparing the color to that of a standard “black body” (an idealized physical body that absorbs all electromagnetic radiation) at a certain temperature. Color temperature is expressed in Kelvin (K). For example, a color temperature of 5,000K corresponds to the color of light produced by a black body when heated to a temperature of 5,000K. As a frame of reference, the color temperature of natural daylight ranges from 5,000K to 6,500K. The color rendition index (CRI), the most misunderstood of all lighting metrics, is used to assess the impact of the light source on the perceived color of an object. It measures how accurately the light source of a given color temperature creates the colors of the object being lit when compared to a light source of the same color temperature generated by a black body. A set of eight standard color samples is illuminated by the light source and by a black body matched to the color temperature of the light source. If none of the samples change color appearance, the light source is given a CRI rating of 100. The CRI decreases as the average change in color appearance of the samples increases. A CRI rating of 80 or above is considered good. It is important to remember that CRI is calculated for light sources of a specific color temperature, so it is not valid to compare, say, a 2,700K 82 CRI light source to one of 3,500K 85 CRI. THE OPERATING CHARACTERISTICS OF LEDS AND WHAT AFFECTS THEM Given that the main purpose of LEDs for our application is the generation of light, it is important to understand what factors impact the light output and the life of LEDs, and how. We know that the light output of currently used light sources, such as fluorescent and metal halides, degrades over time, affecting both the amount of light produced and the spectrum of the light that is output. Typical lamp replacement times are 6-9 months for fluorescents and 9-12 months for metal halides. LEDs, on the other hand, promise a lifetime of 50,000 hours, which is 11.4 years if used 12 hours per day. Proper operation of LEDs requires an understanding of the relationship between forward voltage and current and its impact on light output, as well as on the life of the LED. The amount of forward voltage and current required by an LED is determined by the semiconductors used and is readily available from data sheets provided by the manufacturers. The amount of light emitted by an LED is proportional to the amount of current passing through the device in the forward direction. As the current is varied, the light output will likewise vary, with higher current producing more light. The power supplied to LEDs is regulated by LED drivers (the electronics needed to control the voltage and current). The drive circuits for LEDs must provide suf- ficient voltage to overcome the forward voltage drop at the diode junction (where photons are released), while regulating the current to the correct value for the specific device. The fact that the same LED can be driven at different current levels (350, 700, or 1000 mA) allows for the creation of 1- to 3-watt LEDs using the same LED chip. One factor that significantly affects the life span and spectral characteristics of an LED is heat. Both light and heat are produced at the junction of the diode that makes up the LED device. Any input energy that isn't converted to light is released as heat. Heat is produced by all lighting technologies. The biggest difference between the heat produced by LEDs and that produced by metal halide and fluorescent lighting is that the latter two have a large component of infrared radiation, whereas an LED does not produce infrared radiation. The heat produced by LEDs takes the form of conductive and convective heat. Figure 5 (page 43) shows the typical distribution of heat for different light sources. Although LEDs do not heat aquarium water directly in the manner of a conventional light bulb, heat does have a significant impact on the performance characteristics and life span of LEDs. The temperature at the junction is a key metric for evaluating LED product quality and life. The junction temperature is affected primarily by the drive current, the thermal path, and the ambient temperature. An increase in temperature leads to a change in the forward voltage, which results in a proportionately larger increase in forward current, which further heats the junction. The increase can be controlled by driving LEDs with constant current drivers. The light output of LEDs increases with increasing drive current, which is why the same LED can be driven at varying power. However, this comes at the cost of efficiency. The change in lumens/watt at different levels of current does not result in a linear change in output. Doubling the current does not double the light output. Furthermore, increasing the current also increases the heat generated and the heat-related effects, which in turn necessitates increased heat dissipation efforts. The data provided by manufacturers in most advertising materials often reflects a junction temperature of 25deg;C. In practice, most LEDs operate at higher junction temperatures. Higher temperatures result in lower light output, changes in the light spectrum due to changes in dominant wavelength (ranging from 0-030.13 nm/C), and, most important, a reduction in the life of LEDs. Figures 6-7 (page 43) show the impact of temperature and current on the light output and life of LEDs. As seen in Figure 6, as the junction temperature increases, light output decreases. This loss is generally higher for white LEDs than for blue LEDs. As Figure 7 shows, increasing the drive current increases the light output, double the light output, but also reduces the efficacy. The best compromise of light output and efficacy occurs where these two curves intersect. Air temperature plays a role in thermal transfer between the LED and the surrounding air. The junction temperature and drive current both impact the LED's predicted lifetime. The huge impact that heat has on the LEDs requires that this heat be managed in an effective manner. Heat must be moved away from the die (the small block of semiconductor wafer where light is emitted) in order to maintain expected light output, life, and color. The amount of heat that can be removed depends upon the ambient temperature and the design of the thermal path from the die to the surroundings. Heat must be conducted away from the LED in an efficient manner, and then removed from the area by convection. The final removal of heat can be accomplished passively, for example using a finned aluminum heat sink with a large surface area, but higherpower arrays may require active convection via forced-air cooling (fans) or even water cooling. Heat transport is a critical element in the design of an LED fixture. The need to use materials that are highly conductive, which can be expensive, leads to trade-offs between cost, performance, manufacturability, and other factors. LED DRIVERS LEDs are low-voltage light sources that require direct current (DC) to operate. The LED driver performs several critical functions—converting the incoming alternating current (AC) power to the proper DC power, regulating the current that flows through the LED during operation, and protecting against line voltage fluctuations— and is analogous to the ballast unit in a fluorescent or High Intensity Discharge (HID) lighting system. Drivers can also perform other control functions. They can dim the light by reducing the forward voltage or using pulse width modulation (PWM) via digital control; PWM allows dimming with minimal color shift in the LED output. There are basically two approaches to driving LEDs: constant voltage or constant current. A constant voltage driver is most commonly implemented via a voltage source significantly higher than the diode forward voltage drop and a resistor in series. There are two main drawbacks to this design. Since the diode current depends exponentially on the voltage, a small variation in voltage results in a large change in current. Further, the forward voltage decreases with temperature and this results in a significant increase in current, which increases the junction temperature even more and can create a runaway current. The resistor in series is used to limit the current and control the impact of the shifts in forward voltage. The resistor also provides the ability to compensate for a decrease in light output due to higher temperature. However, this reduces the efficiency due to increased power consumption at the resistor. The preferred approach is the constant current source, which provides the ability to maintain a steady forward current through the LED as the voltage drop across the LED junction varies. The constant current source also allows for variations in the power source of the LED circuit, without affecting LED forward drive current. As a result, the LED lights will provide a continuous luminous output during operation. LED BINNING Due to the variability inherent in their manufacture, and the fact that each silicon wafer in an LED has 50-100K chips that may vary in color and intensity, LEDs are tested and sorted into “bins,” categories based on several measured parameters such as luminous intensity, forward voltage, and dominant wavelength. This is done to provide color consistency and homogeneity within a given product. LED LIFE SPAN Manufacturers often provide LED life span data. Two types of data are often cited. The traditional source lifetime is calculated according to the B50 standard, which provides data on the number of operating hours after which 50 percent of the population will fail. However, LEDs typically do not burn out like incandescent, fluorescent, and metal halide lamps, hence this data is not useful or easily available. Instead, the decline in light output is calculated. The L70 is based on lumen depreciation (or lumen maintenance) or hours of use before an LED drops to 70 percent of its initial lumens. DIRECTING LED LIGHT Because LEDs are built using surfacemount technology on planar substrates, they are surface emitters of light and generally exhibit half-space emission, unlike metal halide/HID lamps and fluorescent lamps, which emit light in a 360-degree pattern. This is an advantage for lighting an aquarium, since the light is required mainly in the half-space below the lighting fixture. Traditional lighting technologies require the use of reflectors to direct the light downward into the aquarium. Typical LEDs have a light spread angle of around 120°, depending on the design of the LED die, and, as with any other source of light, the light intensity is highest at the central axis and reduces toward the periphery. The distance of the surface to be illuminated from the light source and the light-spread angle determine the intensity of the light falling on the surface. As the light source moves further away from the surface to be lit, the light falls on a much larger area and is reduced in intensity. Secondary optics are often used to further focus the light so that higher intensity can be maintained at the expense of the spread of light. LED optics can be either lenses or reflectors. Lenses tend to be more efficient than reflectors at shaping the light beam. Collimators are lenses that can be used to change the beam angle and the divergence and shape of the beam. They are typically designed for specific LEDs and must be used in conjunction with those LEDs. A typical design is a collimator lens that spreads the light on the surface in a specific angle. Collimator lenses are available in varying angles, and they can be made of glass or optical plastic (such as acrylic or polycarbonate). The choice has an impact on the manufacturing (and subsequent retail) cost and quality. Tertiary optics are used to further vary the distribution of light and may protect the elements of the LED system. LED optics are particularly helpful in increasing the light's intensity and ability to penetrate deep into the water column. But since light spread is sacrificed, it may be necessary to add more LEDs to a fixture. Adding secondary and/or tertiary optics to an LED can easily increase its cost by 25-50 percent. Choosing too narrow an optic can create further problems with blending of light. Fixtures for reef aquariums often use a mix of blue and white LEDs. Using secondary optics with narrow distribution can result in poor mixing, resulting in spots of white and blue light. This can be mitigated to some extent by the proper design and spacing of LEDs, and is less apparent further from the light source. INTEGRATION OF LED LIGHTING SYSTEMS A typical LED system comprises several major components, each of which has been discussed earlier. The costs, reliability, and performance of a system depend on the components chosen and how they are integrated. Hence, rather than focusing on LED efficacy and life alone, in practice it is necessary to have an overview of all the components and the impact of efficiency losses (optical, thermal, driver, etc.) throughout the system. These losses may combine to lower LED efficiency by as much as 40-60 percent. Typical optical efficiency through secondary optics is between 85 and 90 percent. Depending on the placement of the secondary optics, there may also be light loss when some of the light is reflected back into the fixture, especially when reflectors are used Thermal loss relates to the decrease in light output as its design, passive versus active cooling for heat removal, and choice of pathways for heat transport will all play a role in the design of the system. Passive cooling relies on a large enough surface area and mass to spread the heat and on the difference between the ambient and heatsink- surface temperatures. Active cooling relies on the forced removal of heat via fans to increase air flow and hence the rate at which heat can be removed. A passively cooled LED fixture operates quietly, while an actively aircooled fixture creates fan noise. The fans themselves are another potential point of failure in the system. Heat also degrades other components, such as lenses and encapsulants, substrate connection materials, and onboard electronics. LED driving electronics do not convert power with 100 percent efficiency. Electrical losses in the driver decrease the overall system efficiency by wasting input power. Electrical losses due to driver inefficiency can be anywhere between 10 and 20 percent, and high-efficiency drivers typically have much higher costs. MULTI -CHIP AND RGB LEDS Typical LED chips measure around 300 micrometers on each side and are packaged into individual LEDs that include the wire leads, epoxy encapsulant, and heat sink. A typical lighting fixture for aquarium use requires several hundred 1-watt LEDs or several dozen 3-watt LEDs, which must be assembled, wired, driven, and thermally managed. New developments in LED technology have resulted in multi-chip LEDS that may incorporate several hundred chips in a single LED package. Multi-chip LEDs are available in power ratings from 10-100 watts, and can provide an alternative to using a large number of lowpower LEDs. Heat dissipation from large chips is focused on a relatively small area compared to heat dispersal from several separate lamps in a large lighting fixture. Due to the intensity of the heat, more heat must be dissipated. In addition, there is a drop-off in external quantum efficiency as chip size increases; a drop-off of more than 25 percent has been reported for chips with an area of 1 square millimeter. There are several new LED fixtures for aquarium use that implement this multi-chip LED technology (e.g., Ecoxotic Photon Cannon in 50W and 100W versions). Another variation of the multi-chip design is one produced by DiCon, in which several individual high-output LEDs can be packed into a high-density array on metal substrates to improve heat transfer. Differently colored LEDs can be mixed in the array to create light with better mixing than that achieved using pegboard fixtures with alternating white and blue LEDs. Multi-chip designs also have a single large light optic, as opposed to having one for each individual LED. Other developments in multi-chip LED technology include the development of multicolor chips—LEDs that incorporate differently colored chips (e.g., white, red, blue, green) in a single unit and provide separate driving controls for each color. These LEDs allow adjustment of each different color and fine-tuning of the appearance of the light. Using more sophisticated controls can provide the user with infinite possibilities for adjusting intensity and color. LEDS AND THE AQUARIST The aim of this discussion so far has been to provide a basic understanding of how LED systems operate and what impacts their operation and life span. Now we will focus on the practical elements of LED lighting to assist aquarists in choosing and using LEDs for their aquariums. Efficiency. Up to 200 lumens/watt may be commercially available in the next few years, and LEDs will have the highest lumens/watt rating of any light source in the near future. Even current-generation LEDs are capable of providing more lumens/watt than fluorescent and metal halide systems. LEDs provide light comparable to that of a metal halide or fluorescent setup, but use less power, resulting in lower electricity bills and “greener” reef systems. Design freedom. LEDs have a fairly small form factor or required design space, and hence offer a wide variety of sizes and shapes, permitting aesthetic designs that are hard to achieve with large metal halide reflectors and fluorescent lamps. LEDs can be packaged as spotlights, strip lights, or combinations of different colors of LEDs, providing the opportunity to be creative in lighting a reef aquarium. Spotlights can be used to highlight certain corals or areas of the reef. Blue strip lights can replace the actinic fluorescents that are very common in reef aquariums. Mixing differently colored LEDs and using the dimming feature of the drivers creates various lighting effects, such as moonlight, dawn/dusk, and even cloud effects during the day, using a single luminaire fixture and exploiting the controllability possible with built-in or wireless controllers. Selective dimming of differently colored LEDs allows the user to fine-tune the color and achieve a wide range of color temperatures. The picture at the top of page 47 shows the range of designs of various LED fixtures available from Ecoxotic. No heat or UV. Both metal halide and fluorescent lighting generate infrared heat that warms the water column, often necessitating the use of a chiller to maintain temperatures below 80°F. The cost of chillers and the associated power usage can be a large component of the setup and operational costs of a reef system. As seen in the technical discussion, LEDs do not produce any infrared heat, so there is no additional transfer of heat to the water and chillers are not required. On the other hand, using LEDs could necessitate the addition of a heater, depending on the ambient temperature. LEDs do not generate any UV light unless specific UV LEDs are used. Long life and low maintenance. The life span typically claimed for LEDs (where they produce 70 percent of the initial light) is around 50,000 hours. While this may be true under ideal conditions, a typical LED fixture often has a shorter life, depending on the quality of the system components, the system design, and the manufacturing quality. Even if we assume a more conservative estimate of 60-70 percent of the figure claimed, this means that a well-designed LED system could be used for five to seven years without having to change bulbs. This would represent a significant cost savings, given that most reef aquarists change fluorescent lamps every 6 to 12 months and metal halides every 9 to 12 months. While all these advantages are significant in their own right, they are beside the point if the LEDs fail to provide the light your corals need. The question is, how much light do corals actually need? Based on the experiences of many hobbyists over years of successful reef-keeping, we know that corals can adapt to and thrive in a wide range of lighting conditions. Specific guidelines for individual corals are hard to obtain, but on the basis of my experience measuring light levels in aquariums, the box on page 47 provides a reasonable guide. The light requirements of corals are usually expressed as photosynthetic photon flux density (PPFD) and measured in micromoles/m2/sec. This unit of measurement is quite different from the lumen measurements used to specify light output based on human vision. When measuring in lumens, light output is weighted differentially, with green given the highest weight and red and blue given much lower weights. This is expressed as a photopic curve and defines the luminous efficiency function. However, where photosynthesis is concerned, all photons of light are treated equally, hence this weighting is not necessary. Unfortunately, LED manufacturers do not provide data in terms of micromoles/mVsec, and it is not possible to convert from lumens to PPFD without explicit knowledge of the spectrum. There are special light meters, known as quantum meters, available that can measure light as micromoles/mVsec, which basically is a measure of the number of photons falling onto an area measuring 1 m2 in one second. Using a quantum meter, the light spread from LEDs can be measured and compared with the requirements of the corals to establish whether the LED light can provide adequate light for their growth. Empirical observations seem to indicate that if the light can generate coverage of the bottom of the aquarium at a light level of 100 micromoles/mVsec, there will be an adequate light gradient across the vertical cross-section of the tank where corals can be placed. Corals with a high light requirement will readily thrive in the upper third of the tank, with adequate light at the bottom for those with a lower requirement. Detailed analysis and comparison of LED fixtures and their light output is available online and is not the focus here. Suffice it to say that the range of choices available to aquarists is expanding rapidly, with options for all budgets. Every aquarist will have to decide for himself or herself what benefits LEDs provide compared to other, longer established lighting technologies—or even more radically new choices, such as plasma lighting—and whether they warrant the purchase of LED lighting now or in the future. SanjayJoshi, Ph.D., professor of industrial and manufacturing engineering at Perm State University, University Park, Pennsylvania, will discuss plasma lighting in a future issue of CORAL.

Hi Tony, welcome to SRC. Great dive photo, and I a fan of your books.

Click through to see the images. The convention cost will be $15 per person via PayPal. Register now! Agenda Friday Night: ~ 7:00pm - meet & greet at Harry's Pub in hotel Saturday: 8:30am: doors open 9:00am: Intro / Welcome Tony Morelli (tonmo) 9:20am: Displaying and breeding Cephalopods at the California Academy of Sciences - Richard Ross (Thales) 10:00am: Ethics Roundtable - Moderated by Katherine Dickson (neurobadger), with Greg Barord, and Richard Ross 10:50am: ~10 Minute Break~ 11:00am: Nautilus Conservation - Greg Barord (gbarord) 11:40am: Identifying Commonly Kept Octopuses - Denise Whatley (DWhatley) 12:20pm: Break for lunch - will be "on our own" 1:00pm: WAMAS 1:30pm: A Vampire's Blind Mouth - Adam Eli Clem (Clem) 2:10pm: Colossal Investigations - Olaf Blaaw (OB) 2:50pm: Kraken: The Curious, Exciting, and Slightly Disturbing Science of Squid - Wendy Williams 3:30pm: ~10 Minute Break~ 3:40pm: The Octopus Mind - Peter Godfrey-Smith (pgs) 4:30pm: Thank You and Monty Awards - Tony Morelli (tonmo) 5:00pm: Go our own way (groups will break off) 6:00pm: Meet at the Invertebrate Exhibit at the Nat'l Zoo (exclusive access for people at TONMOCON IV) 9:00pm: meet at some bar. Sunday: [*]Informal gatherings for breakfast, National Zoo, etc. View the full article

A study into the muscle development of several different fish has given insights into the genetic leap that set the scene for the evolution of hind legs in terrestrial animals. This innovation gave rise to the tetrapods -- four-legged creatures, and our distant ancestors -- that made the first small steps on land some 400 million years ago. View the full article

A study into the muscle development of several different fish has given insights into the genetic leap that set the scene for the evolution of hind legs in terrestrial animals. This innovation gave rise to the tetrapods -- four-legged creatures, and our distant ancestors -- that made the first small steps on land some 400 million years ago. View the full article

A fish's personality may determine how it is captured. This association between personality difference and capture-technique could have significant evolutionary and ecological consequences for affected fish populations, as well as for the quality of fisheries. View the full article

Fish quantities off the Norwegian coast fluctuate widely from year to year. For 150 years, scientists have tried to figure out why -- and now they are nearing an explanation. View the full article