When a fishing guide takes you out and you don't catch any fish, he may say "Gee, you should have been here last week, they were jumping into the boat." Yeah, right. When a dive master takes you diving and you come up ask where the coral reef is, she may say, "Gee, you should have been here 40 years ago; it was healthy and beautiful with coral growth and tropical fish all over the place." And so it was. And I was there also. Coral heads were massive, great stands of elkhorn coral reached for the surface and the shallow reefs were topped with extensive growths of fire coral, Millepora complanata. All of these corals had different species of fish and invertebrates that live to a greater or lesser extent within the special environment that that species of coral creates. Food, shelter, reproductive substrates-the coral provide the special environmental conditions that helped that species survive in the "eat or be eaten" world of a coral reef. And it was, and still is, one of the most wondrous environments on Earth.

The company I started in 1973, Aqualife Research Corporation, moved to Marathon in the Florida Keys in late 1974 and I had the great opportunity to live, work, and dive in the Florida Key for ten years. Forrest joined me in, I think it was 1978, and we worked together until 1984 on the culture of clownfish, gobies, Atlantic angelfish, and many other species of reef fish, including the yellowtail reef fish, Microspathodon chrysurus. The juveniles of this species carried the common name of jewelfish at that time because of the brilliant iridescent blue spots that covered the body. These spots disappear as the fish attains the adult coloration of a drab dark brown body and bright yellow tail. Despite their aggressive nature, their constant movement and bright coloration made them a popular fish for marine aquariums at the time. They are a good species for reef tanks if kept one per tank.

Jewelfish lived in the fire coral reefs, they fed on algae and invertebrates that occupied these reefs, and they laid their eggs on the dead blades of the fire coral. In fact I seldom saw yellowtail reef fish except with a growth of fire coral, however small, right near them. I remember back in the mid 70s, I would hover at the edge of the fire coral reef and look over the relatively flat surface of the reef. After a while I would see male jewelfish in specific areas scattered widely over the reef popping up and flashing, dropping down into the reef and moments later popping back up, and repeating this behavior over and over again. They were tending to their nest of eggs on fire coral blades and trying to attract a female to stop by and drop off a few eggs, maybe 400 or so, to enlarge the nest that the male was tending and guarding.

I recall the first time I checked this out and found a large nest of eggs on a dead blade of fire coral. I hit the top of the blade breaking it off near the bottom. It was about 8 inches long and had more than a thousand eggs, the results of several spawns all over one side. I picked it and got very excited when I realized that I had in my hand potentially $50,000 worth of juvenile jewelfish, if I could only rear them. (But I knew then, as now, that flooding the market with one species, leads to very much lower prices and excessive unsold inventory.) But still it was certainly worth it to rear some of them.

There was considerable interest and competition in the very early days of marine fish culture and we played our cards pretty close to our vest in those days. Thus the article below from the May 1981 issue of Freshwater and Marine Aquarium Magazine (price $1.50) did not provide many details as to exactly how we reared them. But the secret was, of course, copepods from wild plankton as a first food. Suspending the blades of fire coral with their nests of jewelfish eggs in a large larvae rearing tank with a heavy flow from an air stone release underneath them was all it took to keep them alive during development and stimulate hatching when the embryos were ready.

Back in those days, rearing marine tropical fish was a quixotic exercise of producing an expensive cultured fish that competed with an inexpensive wild caught fish in a market that was highly price competitive. But still, the promise of what could be, and what would probably be, drove adventurous souls like Forrest and me to invest more of ourselves into a culture that really didn't make a lot of economic sense at the time. But some dreams never die…

Unfortunately, however, the coral reefs, at least what they were in 1970s and early 80s, did die, or at least greatly diminish. Those vast expanses of fire coral that topped the reefs are gone, and so also the yellowtail reef fish and their stunningly beautiful jewelfish juveniles are now very hard to find. Florida's coral reefs have declined for many reasons: pollution, storms, overfishing, over visitation, and disease of both corals and invertebrates. Perhaps the most critical loss of biodiversity was the almost total annihilation of the keystone herbivore of the Atlantic coral reefs, the long-spined sea urchin, Diadema antillarum, in a great plague that swept from the Panama Canal through this great oceanic region all the way to Bermuda in the space of 13 months in 1983. Within weeks macro algae began to overtake the Atlantic coral reefs and this is still the case today. These urchins have not recovered, their ecological function of herbivory is still absent and the reefs continue to decline. But now we can culture these difficult urchins, and after six years of effort I am close to completion of a functional technology for small scale urchin larvae culture, and I hope that this will stimulate more effort to restore this keystone herbivore to Atlantic coral reefs. Then perhaps the fire coral reefs and the jewelfish will return.

- Martin Moe

 

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Spawning the Jewels of the Reef

Freshwater and Marine Aquarium magazine, May 1981
By Martin A. Moe & Forrest A. Young
Aqualife Research Corporation

The yellow-tailed damselfish, Microspathodon chrysurus, or marine jewelfish as it is known in the hobby, is one of the hardiest and most colorful of the Atlantic damselfish. Juveniles exhibit a striking coloration of iridescent neon blue spots against a midnight blue background. This fades in intensity as the fish matures and only a few small blue spots remain on the drab, dark brown adult. Also, the color of the caudal fin changes from clear in the juvenile to a bright yellow on the adult, hence the origin of the accepted common name.

In nature, adult and juvenile jewelfish arc found almost exclusively among the flat, branching growths of fire coral, principally Millepora complanata. The fire coral affords the jewelfish protection from predators, reproductive sites, and even food since stomach contents are composed of algae and detritus common to fire coral reefs as well as elements of the fire coral itself. Ciardelli (1967) examined stomach contents of juvenile jewelfish and found a variety of vegetable and animal matter including nematocysts (stinging cells) that apparently were from Millepora. He feels that the ingestion of fire coral by juvenile jewelfish may explain their close relationship with the shallow fire coral reefs. Unlike other damselfish in the same environment, Randall ( 1967) reports that jewelfish were never observed feeding on planktonic organisms, but restricted their diet to benthic algae with a small amount of animal matter. He also describes cleaning behavior, removal of ectoparasites by juvenile jewelfish from large grey angelfish. Emery (1968) reports that benthic animals are important in the diet of the juveniles, including coral polyps and sponge, and that adults gradually switch to almost exclusively benthic algae.

The association of jewelfish with fire coral is so exclusive that we consider it a form of commensalism. This association is not as obvious as the spectacular commensalism of clownfish, Amphiprion sp., with anemones, but seems to be almost as obligate to the fish. It is extremely rare to find a jewelfish without at least a small growth of fire coral in the immediate environment. Further observation and ecological analysis of this association is needed to clarify the relationship between fire coral and jewelfish.

Jewelfish are beautiful and hardy and. although they are very aggressive toward others of their species, they are good solitary aquarium fish and are an excellent prospect for commercial culture.

Aqualife Research Corporation first reared jewelfish into large juveniles in mid 1976 and developed the techniques for large scale culture in late 1978. Almost 1000 individuals were reared in a single tank during this period, so tank reared jewelfish should soon be available to the hobby. Jewelfish, like other pomacentrids such as clownfish and damselfish, are demersal spawners and adhere their eggs to coral structures near the top of the reefs. Each species of damselfish has a particular place and substrate favored for nest building. Jewelfish eggs are much smaller than clownfish eggs and, like clownfish eggs, are attached at one end to the spawning site. The nests are composed of tiny, I mm diameter elliptical eggs densely packed on a coral substrate. There is an average of about 1,150 eggs per square inch of nest, and one nest with eggs in various stages of development may easily cover 20 to 80 square inches, a total of 23,000 to 92,000 jewelfish eggs on each spawning site. The eggs are translucent with a pinkish cast when newly laid and become darker as the embryo develops and hatching time approaches. The eyes are fully developed at hatching and are the most noticeable feature of the late stage embryo and early hatchling. The time from spawning to hatching is about 3 days at 80 F (27 C) and hatching usually occurs at night.

The newly hatched larvae are so small, less than l/16" long, and so slight and transparent that they are almost invisible. Those that peer into a tank of newly hatched jewelfish for the first time are incredulous that they cannot see a one of the 15,000 fish that are swimming about in the tank. However, a little searching soon reveals the presence of the diminutive larvae. One newspaper reporter was sure that he had drunk water with more critters in it than he could see in a tank of larval jewelfish.

Jewelfish larvae are much smaller than clownfish larvae and appear very similar to larval angelfish to the unpracticed eye. Some species of marine fish, such as the neon goby, metamorphose very quickly from larval to juvenile coloration and behavior patterns. This change to the juvenile characteristics occurs actually overnight in some instances, although most species require a few days to make the complete transformation. Other species, like the jewelfish, go through a prolonged period of gradual change and the juvenile characteristics are acquired very slowly. The post larval period is passed in the form of a creature adapted to the pelagic environment rather than one living secretively among the bottom growths.

The larval period for jewelfish extends to 4 weeks and the post larval period may take an additional 3 to 4 weeks before juvenile form and color are attained. The total length of the fish exceeds 1/2" before the Post larval period is complete. The most obvious structural development of the larval jewelfish is the greatly enlarged pectoral fins. During this early period, the pectoral fins extend posteriorly to almost the caudal fin and spread outward a distance equal to about the depth of the body. These large laterally spread fins greatly increase the horizontal surface area of the fish, an adaptation that provides support and mobility in the pelagic environment. These pectoral fins are always spread and give the diminutive fish the appearance of flying through the water. ln fact, they look for all the world like miniature delta wing aircraft pursuing some important mission as they cruise tirelessly throughout the tank. They pause only to sight on and strike at food organisms.

There is a price that must be paid for this extraordinary larval mobility and restless behavior. Some other species, such as angelfish and reef drum, (jackknife fish) have slow moving sedentary larvae that seem to expend their energy only at the moment of striking at the prey organism. These larvae grow much faster than jewelfish and enter the benthic juvenile stage in only 2 to 3 weeks, less than half the larval period of jewelfish. Of course, tank reared marine fish larvae experience an unnatural environment and behavior and growth cannot be assumed to be exactly the same as wild fish, although parallels certainly exist.

Apparently, jewelfish require fire coral reefs for survival in the wild, and this type of habitat, while not at all a rare kind of reef formation; it still does not cover broad expanses like grass flats or the soft coral - hard rubble bottoms. A journey of many miles might be required of the tiny post larval fish before it encounters a fire coral formation. We consider it quite possible that the extensive pectoral fin development, active swimming mode, and the prolonged period of larval and post larval stages are adaptations that provide young jewelfish the means of finding the relatively restricted type of habitat required for survival. Jewelfish are distributed on fire coral reefs from Florida to Brazil and the extended duration and mobility of the early stages must enhance such wide distribution to a restricted habitat. The energy expended in the larval stage slows growth and prolongs the dangerous pelagic period, but these disadvantages are apparently compensated by the ability to find the fire coral reefs.

As mentioned above, juvenile jewelfish feed mainly on sponge, algae, hydroids, isopods, and copepods so they adapt well to the typical aquarium diet. Since adults feed almost exclusively on benthic algae, a diet rich in vegetable matter is suggested as they mature. They take a wide variety of foods including live or frozen brine shrimp, flake foods and finely chopped shrimp.

Jewelfish make an excellent addition to a community tank. They are impressively colorful, are very active and often engage in transport of stones and objects from their home area. They may also show cleaning behavior on the larger fish in the tank. Unless the tank is quite large, however, only one jewelfish should be kept per tank because they are highly territorial and eventually the dominant fish will destroy his few unfortunate brethren. Aggressiveness toward others of their kind is not restricted to jewelfish, although they are quite good at it. Many coral reef fish are strongly territorial and will drive cognates that compete for food and shelter away from their premises. The weaker fish is only too happy to flee and find his own piece of the rock, but containment in 4 glass walls with his adversary soon leads to his demise. On the other hand, the presence of many small fish of the same species in the same tank, in this case, jewelfish, seems to diffuse their aggression and 30, 50, 100 or more can coexist and grow in a relatively small contained area. Otherwise, they would be most difficult to rear in large numbers to aquarium size. Aqualife Research Corporation has already made a few shipments of tank reared jewelfish to various dealers and, hopefully, many more will be available in the near future.

References

1. Ciardelli. A. 1967. The Anatomy of the Feeding Mechanism and the Food Habits of Microspathodon crysurus (Pisces: Pomacentridae). Bull. Of Marine Sci. Vol. 17. No. 4. PP 845-883.
2. Emery. A.R. 1968. Comparative Ecology of Damselfishes (Pisces: Pomacentridae ) at Alligator Reef. Florida Kevs Dissertation, University of Miami. Coral Gables, Florida, 258 Pages.
3. Randall, J. E., 1967, Food Habits of Reef Fishes of the West Indies. Studies in Tropical Oceanography, No.5. pp. 665-847.

While a great deal of interest has been shown in the characteristics of artificial daylight for reef aquaria, very little attention has been paid to the other natural illumination - moonlight. Although manufacturers have marketed moonlight simulators for a number of years, I've yet to see an in-depth discussion of the subject. This article will attempt to address that issue while discussing some misconceptions about lunar light. In addition, we'll define spectral characteristics of moonlight, light intensity, and length of natural lunar photoperiod, and ways to simulate moonlight. We'll also examine the effects (or non-effects) of moonlight on timing of coral spawning (and comment, albeit briefly, its effects on fish spawning behavior).

Lunar Photoperiod in Hawai'i

As we know, the lunar cycle consists of 29.5 days and is the basis for our calendar month. The lunar phase changes in a predictable manner and is due to relative positions of the moon, earth, and sun. Phase is not due to the earth's shadow falling upon the moon (this is referred to as a lunar eclipse). Figure 1 shows phases and approximate and approximate days of the lunar month.

Figure 2 shows the hours of potential moonlight in Hawaii. Data are based on times of sunrise/sunset and moonrise/moonset.

Moonlight Spectral Characteristics

Since moonlight is almost entirely reflected sunlight, one might reason that the moon's spectral signature is exactly that of sunlight - it is not. Data shown in Figures 3 & 4 reveal that moonlight is less blue and redder than sunlight (and this measurement was taken with a 'silvery' moon at its zenith. We often see a much more orange moon at moonset).

Moonlight Intensity

Moonlight intensity is determined by lunar phase and sky conditions. Figure 5 shows moonlight intensity (in lux) under ideal conditions. Figures 6 and 7 show full moon light intensities (PAR) as measured during two nights (just a few feet above sea level). Note that the intensities are lower than that reported by Jokiel (0.05 µmol·m²·sec, or about 1 lux). The low moonlight intensity reported here is due to a number of factors, including seawater aerosols in the air, thin high level clouds, and vog (a mixture of atmospheric moisture and volcanic smoke from the Pu'u O'o vent and Halema'uma'u caldera of the Kilauea volcano).

Factors Influencing Coral Reproduction - Order of Importance

Moonlight is but one factor influencing coral reproduction. If other factors (nutrition, physical parameters, etc.) are correct, these are believed to be important:

Temperature: Temperature seems to exert powerful control over coral reproduction. If the temperature is too high, coral health can suffer, while cool temperature may delay spawning until the next month's window (Hunter, 1988; Riddle personal observations). Temperature has been stated to be the influence of paramount importance in the reproductive cycles of marine invertebrates (Olive, 1995). In Hawaii, the temperature threshold is about 75F (24C; Dr. Paul Jokiel, personal communication).

Moonlight: Lunar cycles set the date of spawning in many coral species and the lunar calendar can be used to accurately predict it.

Daylight Photoperiod: Solar photoperiods influence coral reproductive efforts and set the hour and minute of spawning (Vize et al., 2008). The time of sunset is the fine-tuning factor for many marine invertebrates including at least some sponge and coral species.

Corals Don't Have Eyes - How Do They Sense Light? And What Do They See?

Gorbunov et al. (2002) found blue light at about 480nm (110nm width, half maximum) at very low light intensity caused a reaction among coral tentacles,although a description of photoreceptors involved was not part of the experiment.

In 2003, Levy et al. exposed corals (azooxanthellate Cladopsammia gracilis) the bubble coral Plerogyra sinuosa, the flower pot coral Goniopora lobata, Favia favus, and Stylophora pistillata) to various light wavelengths (400-700nm at 20nm intervals) and intensities (10µmol·m²·sec and 30 µmol·m²·sec; ~500 lux and 1,500 lux, respectively) and recorded tentacle contractions. Cladopsammia did not respond to any light treatment, while Plerogyra sinuosa and Favia favus contracted their tentacles when exposed to wavelengths between 400-520nm (violet-blue-green). Interestingly, Favia favus also responded to red light (660-700nm) at 30 µmol·m²·sec or ~1,500 lux (see light sensitivities of rhodopsin-like compounds and cryptochromes below).

Five years later, a rhodopsin*-like compound was found in the stony coral Acropora millepora (Anctil et al., 2007), explaining how corals sense light. Almost simultaneously, Levy et al. (2007) described cryptochrome** proteins sensitive to blue light in Acropora millepora. Other researchers have noted corals' responses to light suggesting rhodopsin-like compounds are found in at least some corals.

This ability to sense light explains how corals can grow towards light, and if overturned, can redirect their growth (this is call phototropism). It also explains how corals set their biological clocks through sensing daylight and moonlight.

*Rhodopsin is a photosensitive pigment found in many animals' eyes (including humans) within receptors called cones. Cones and their rhodopsin content enable us to see in very low light conditions. Rhodopsin collects light in wavelengths of about 400nm (violet) to red (at ~600nmn) but most strongly in the blue-green portion of the spectrum (Hunt, 1987).

**Cryptochromes (Greek for 'hidden color') are proteins sensitive to blue light and are found in photoreceptors of plants and animals.

Entrained Biological Rhythms versus Response to Environmental Factors

The act of coral spawning involves production of a number of compounds, and this may be the result of entrained rhythms or exposure to external stimuli. For our purposes, entrained rhythms are those that occur without external stimuli such as sunlight or moonlight. These are likely controlled genetically. Environmental factors (such as like or moonlight) can influence the production of compounds. Vize et al. (2008) found photoreceptors signal production of proteins important in annual spawning of the stony coral Montastrea cavernosa.

Fish Reproduction and Lunar Phase

Many fishes are known to spawn synchronously around a certain lunar phase and this timing may be species-specific. For instance, Takemura et al., 2004 discuss lunar phase and spawning of the golden rabbitfish (Siganus guttatus). These fish did not spawn when subjected to constant illumination, and those held in conditions of total darkness at night displayed altered spawning patterns. Pressley (1980) described the relationship of lunar phase and reproduction of the yellowtail damselfish, Microspathodon chrysurus.

It is an interesting notion that circadian rhythms play an important part in fish reproduction and that accurate simulation of lunar phase may be an important factor.

Light Spectra Transmission in Clear Seawater

As mentioned earlier, several researchers have found that some corals respond to blue light. It is perhaps not by coincidence that maximum penetration of light occurs at about 480-500nm. See Figure 8.

Moonlight and Coral Spawning

Moonlight is commonly believed to be one of the deciding environmental factors for timing of coral spawning. Jokiel (1985) examined numerous Pocillopora damicornis specimens and concluded planula release occurred around the time of the full moon. However, Hunter (1988) experimented with two Hawaiian Montipora species (M. verrucosa = capitata and M. dilatata) and found the following:

• Both sets of corals spawned simultaneously with control corals when exposed to constant simulated moonlight (at a flux of 0.01 µmol·m²·sec, or about 0.5 lux)
• When exposed to no simulated moonlight (constant new moon), 43% of the M. verrucosa spawned in sync with the controls, and in the next month, 1 week prior to the new moon. Montipora dilatata specimens also spawned in synch with controls in the first month, and then 8 days out of normal phase the next month.
• When maintained under simulated moonlight shifted 14 days out of phase, both coral species spawned simultaneously with controls, and then 2 to 12 days out of sync in the second month.

Artificial Moonlight

It is usually impractical to expose an aquarium to moonlight hence artificial means are preferred. In my 1995 book, The Captive Reef, I outlined a means of simulating moonlight with a blue incandescent lamp and a manual dimmer. Technology has come a long way since then and light-emitting diodes are now the preferred method. See Figure 9.

Figure 10 shows the typical spectral quality of a LED peaking in the blue portion of the spectrum at ~450nm.

Controllers

There are a number of controllers on the market claiming to simulate timing and variable intensity of natural moonlight. This article is not intended to review all those available. Instead, I describe the one I own - the Tunze Multicontroller 7095. This device's main function is that of controlling Tunze pumps but includes a LED for moonlight simulation. The only thing a hobbyist has to do is turn the moonlight LED on when the real moon is full and the controller automatically does the rest. A photo-sensor will turn the LED moon on when the aquarium lights go out and lunar phase intensity is controlled over a 29 day cycle. See Figure 11 for a close up view of the photo-sensor/LED and Figure 12 shows the spectral characteristics of the LED.

In Closing

Many corals contain photoreceptors (note their ability to almost always grow towards light). Some demonstrate responses to blue light, while at least one species can sense both blue and red light. Some show no response to light.

Moonlight is thought to play an important role in timing reproductive cycles of many coral and fish species. In corals, lunar cycles set the date of spawning, while the time of onset of darkness fine tunes the cycle and decide the hour and minute (then a release of hormones into the water induces mass spawning). An altered lunar phase may at least temporary disrupt spawning synchrony among at least some coral species. Lunar periodicity seems to play a role in timing of reproduction among at least some fish species. Interestingly, short term exposure of some fishes to constant artificial moonlight may have prevented spawning, while the same did not affect the patterns in some corals. It seems apparent that different taxa are affected differently by altered moon phases, if only temporarily.

Although moonlight appears white or silvery, use of LEDs producing blue light to simulate moonlight is, at least for some coral species, correct based to peer-reviewed evidence. Use of LEDs producing white light is likely to be OK as well, since these diodes are essentially blue LEDs doped with phosphors that fluoresce longer wavelengths. However, the light intensity of the light produced by even a single blue LED has the potential to be brighter than natural moonlight measured here in Hawaii. Light penetration in aquaria, with their usually shallow (and hopefully clear!) waters, should not be an issue, so using LEDs with a maximum wavelength of 450 or 460nm may actually be an advantage due to their lower output at 480nm.

Since most PAR meters' minimum respond is '1', these units are useless in determining proper placement of a light source in order to mimic natural moonlight intensity. On the other hand, a lux meter can measure moonlight at its maximum intensity although the reading will be ~1. Hence, placement of the LED for providing proper intensity will likely have to be estimated visually. At present, the effects of over-illumination of a reef aquarium at night are unknown but it is possible that it might affect fish or invertebrate spawning behavior.

A number of controllers with abilities to simulate lunar phase are on the market. In absence of one, a handy hobbyist can make a manually-controller lunar simulator with a low wattage incandescent lamp and a rheostat.

Testing Equipment

Spectral characteristics of the moon and LED were measured with an Ocean Optics USB2000 spectrometer and SpectraSuite software. Data were downloaded to an Excel worksheet for post-processing. Moon intensities were recorded by a Li-Cor 1400 quantum meter/datalogger and cosine-corrected quantum sensor.

Acknowledgement

Thanks to my brother David for supplying the photograph of the moon.

Questions? Comments? Please post below or contact me at RiddleLabs@aol.com.

References

1. Anctil, M., D. Hayward, D. Miller, and E. Ball, 2007. Sequence and expression of four coral G protein-coupled receptors distinct from all classifiable members of the rhodopsin family. Gene, 392(12): 14-21.
2. Brady, A., K. Snyder and P. Vize, 2011. Circadian cycles of gene expression in the coral, Acropora millepora. PLoSOne Online.
3. Gorbunov, M., Z. Kolber, M. Lesser, and P. Falkowski, 2002. Photoreceptors in the cnidarian hosts allow symbiotic corals to sense blue moonlight. Limnol. Oceanogr., 47(1), 2002, 309-315.
4. Hunt, R., 1987. Measuring Colour. Fountain Press, Kingston-upon-Thames, England. 344 pp.
5. Hunter, C., 1988. Environmental cues controlling spawning in two Hawaiian corals Montipora verrucosa and M. dilatata. Proc. 6^th Int. Coral Reef Symp., Australia. 2:727-732.
6. Jerlov, N., 1976. Marine Optics. Elsevier Oceanography Series, Elsevier Sci. Publ. Co., New York. 231 pp.
7. Jokiel, P., 1985. Lunar periodicity of planula release in the reef coral Pocillopora damicornis in relation to various environmental factors. Proc. 5^th Int. Coral Reef Congress, Tahiti. 4: 307-312.
8. Levy, O., L. Appelbaum, W. Leggat, Y. Gothlif, D. Hayward, D. Miller, O. Hoegh-Guldberg, 2007. Light-responsive cryptochromes from a simple multicellular animal, the coral Acropora millepora. Science, 318 (5849):467-470.
9. Levy, O., Z. Dubinsky, and Y. Achituv, 2003. Photobehavior of stony corals: Responses to light spectra and intensity. J. Exp. Biol., 206: 4041-4049.
10. Olive, P., 1995. Annual breeding cycles in marine invertebrates and environmental temperature: Probing the proximate and ultimate causes of reproductive synchrony. J. Therm. Biol., 20(1, 2): 79-90.
11. Pressley, P., 1980. Lunar periodicity of the yellowtail damselfish, Microspathodon chrysurus. Environ. Biol. Fishes, 5:155-159.
12. akemura, A., E. Susilo, M. Rahman and M. Morita, 2004. Perception and possible utilization of moonlight intensity for reproductive activities in a lunar-synchronized spawner, the golden rabbitfish. J. Exp. Zoology, Part A: Comp. Exp. Biol., 301A, 10: 844-851.
13. Vize, P., J. Hilton, A. Brady and S. Davies, 2008. Light sensing and the coordination of coral broadcast spawning behavior. Proc. 11^th Int. Coral Reef Symp., Ft. Lauderdale, Florida.

First, a little history... There had been a lot of activity, experimentation, and commentary in the late 60s and early 70s on the possibility of rearing marine tropical fish in numbers but no one had yet succeeded. I was lucky; I was in the right place at the right time with the right experience. I had worked from 1969 to 1971 developing the technology for controlled spawning and larvae culture of the Florida pompano, and from that I knew what marine fish larvae needed in order to survive. I also picked the right fish with which to begin the work. If I had picked, Oh, pigmy angelfish, for example, I might be still working at it. I explained in the article why I chose the "Percula" clownfish for the first experiments.

At that point, the hobby did not really distinguish between A. percula, the orange and/or percula clownfish, and A. ocellaris, the common and/or false clownfish. In fact, few hobbyists were familiar with taxonomic conventions and the use of scientific names was only something that those fancy pants scientist types used once in a while. In the hobby, the only clownfish that was typically available was the common clownfish, A. ocellaris. But in the popular literature the percula clownfish was most commonly illustrated, and so the common clownfish that filled the tanks of this fledgling hobby was almost universally given the erroneous common name "Percula clown". The two species are very close in morphology; there are some subtle color differences and typically 10 dorsal spines in A. percula and 11 dorsal spines in A. ocellaris. A. percula was described in 1802 by Lacepede, and A. ocellaris in 1830 by Cuvier. Given that A. percula was the first described, that name was most used in the early literature, and thus picked up by the early marine aquarists. Books by Gerald Allen and Daphne Fautin eventually ended the lay confusion (almost) between these species. Now, of course, we also have to contend with numerous "breeds" and hybrids of these same species. It is an exciting time for clownfish breeders.

At that time there were relatively few species of marine tropical fish available to hobbyists. Clownfish were among the most popular marine fish, but also quite difficult because most were collected with cyanide. They were also subject to external parasites, and shipment and early captivity mortality was very high. But even with my experience with pompano, it was a culture project with very little extant information to guide the effort; and with limited resources, a lot of experimentation and intuitive guessing on how to resolve problems was required. The thing that always helped me with development of culture procedures with new species was to learn as much as I could about the natural history of the species under culture, the environment, the diet, the reproductive modes, etc., and use that knowledge as a base for development of adequate substitutes for that organism's basic requirements for survival.

As with the early development of any new technology that holds a promise of commercial value, the early days of marine fish culture were shrouded in secrecy, or least that attempt was made. Thus my article was long on biology and short on technology. It was important, however, to provide enough detail in text and photos to establish with certainty that repetitive culture of relatively large numbers of juveniles had been accomplished. Within a few years, of course, the basic culture techniques, and many improvements as well, soon became relatively well known. Over the years, subsequent articles, books, and websites have provided great detail on the original and many additional techniques. The Marine Aquarium Handbook (now in the 3^rd edition) and my book on rearing the orchid dottyback, many very significant recent articles and scientific papers, and books by Hoff, Wilkerson, and Wittenritch have now greatly expanded knowledge and "how to" information on marine ornamental fish culture. And now the information for large and small scale culture of many species (but not enough) of marine fish is readily available. My original article is of historical interest, but still provides good information on the biology of clownfish culture.

Salt Water Aquarium, The international magazine for marine aquarists

Introductory comments from Robert P. L. Straughan, editor, Salt Water Aquarium magazine

March-April, 1973, Volume 9, Number 2

TANK RAISED CLOWNFISH!
SPECIAL SPAWNING ISSUE
A MILESTONE IN THE HOBBY
BREEDING THE CLOWNFISH, Amphiprion ocellaris
By MARTIN A. MOE, JR., MARINE BIOLOGIST

Breeding marine fish has often been termed impossible, improbable, difficult and prohibitively expensive. It is actually none of these, as this article will show; however, it is time consuming and does require a good deal of specialized knowledge. This is not a "how to" article or a scientific paper since the techniques of rearing are still under development and many problems are yet to be solved, but I hope that it will stimulate increased interest in the hobby of maintaining marine fish and show that the prospect of rearing some of the marine tropical fish in large numbers may not be far off.

Fishes of the genus Amphiprion, particularly the common clownfish A. ocellaris (percula) are among the most popular of marine aquarium fish. Their hardiness, vivid coloration, engaging personality and relative abundance are good reasons for their popularity. These traits alone are cause enough to investigate the possibilities of controlled reproduction and a study of what is known of their life history confirms their candidacy for breeding experimentation. Clownfish are demersal spawners, attaching their eggs to hard surfaces near the base of an anemone. They guard and aerate the eggs from spawning to hatching, a period of 7 to 9 days, after the fashion of cichlids. The larvae are large at hatching, about 4 mm in length, have eyes and mouth parts fully formed, and are ready to begin feeding within the first 24 hours of hatching. The adults mature at small size, 50 to 100 mm, and have a limited range, usually the immediate vicinity of an anemone. These biological characteristics make it relatively easy to provide the necessary environment to stimulate natural spawning.

Dr. Gerald R. Allen (1) has compiled a recent and thorough review of the taxonomy and biology of the genus Amphiprion and he reports in this work of rearing 3 A. chrysopterus and one A. tricinctus through the larval stages on dried particulate food, This and other accounts of rearings of Amphiprion (2) (3) and (4) reported in the literature, made A. ocellaris an obvious choice for the first rearing attempts. The following work was conducted partly as an extension of a hobby and partly as independent research on reproduction in marine fishes while attending the University of South Florida.

Spawning

The project began in July, 1972, with the construction of two 55 gallon tanks destined to serve as spawning aquaria. Costs were cut markedly through constructing all parts of the tanks and filters with inexpensive, readily available materials. (Perhaps the details of construction will form a later article.) One of these tanks was established with natural sea water and small local fish were used to provide the nitrogenous waste to activate the filter bed. The other was filled with artificial sea water and the filter bed was activated chemically with ammonium chloride. The latter method resulted in a more trouble free tank than the former. Each tank was provided with full spectrum lighting and an attractive decor of construction stone. The photoperiod and temperature were adjusted to provide maximum stimulation of the fish's endocrine system and then the trauma of establishing the filters began. The tanks were ready for occupation about mid-September. Four A. ocellaris that seemed to be already mated and two large anemones of the genus Stoichactis were purchased at Scott's Highway Aquarium in St. Petersburg and the experiment began. A diet specially compounded of shrimp, clams, chicken gizzards and certain marine algae and vitamins was fed twice a day. The fish took immediately to the anemones and their general behavior was soon much like that described in the literature for the genus Amphiprion in the wild. The fish spent most of their time bathing in the anemone and hovering just above it protecting their anemone from all real and apparently many imaginary intruders. Movements many feet away from the aquaria would send them charging against the glass or scurrying in rapid retreat into the protective custody of the anemone.

Only one pair engaged in spawning activity. This was the pair that occupied the tank established with artificial salt water, although by this time the initial water had been diluted with natural sea water to reduce the nitrate accumulation. The pair in the tank established with natural sea water and local fish had problems with external parasites and had to be treated several times. Also, as they gained in size the suspicion that they were both females became more of a certainty. They are almost equal in size and both have the roundness of the abdomen that seems characteristic of females.

The spawning pair are unequal in size and vary in general shape. The female is the largest of the pair, approximately 80 millimeters long and has a well-rounded abdomen. The male is about 60 millimeters long and has a narrow abdomen and a much smaller appetite than the female. The first spawning occurred on November 3, 1972. There was some indication of impending spawning in the fullness of the female and for a few days before spawning each fish would occasionally bite gently at the abdomen and vent of the other. Spawning occurred, as it did in all subsequent 5 spawns, in the afternoon hours. About one hour before spawning, the pair actively cleans the rock that will receive the eggs by biting the substrate and aggressively jerking the head from side to side. The afternoon spawning could be accurately predicted in the early morning by the extended ovipositor of the female. The ovipositor, a blunt, rather large pinkish organ, did not retract until several hours after spawning. The male's genital papilla was small, white in color, sharply pointed and appeared only shortly before, during and shortly after spawning. Rapid chasing before spawning or rapid vertical movements as reported by other authors did not occur.

Toward the .end of the surface cleaning activity, the female began to make frequent passes over the rock with the tip of her ovipositor dragging over the cleaned surface. These passes became more frequent until after about 15 minutes the first eggs appeared. These were a bright orange-yellow, about 1 mm in diameter and 2 mm in length. They passed from the ovipositor and immediately adhered by one end to the rock. The female swam in a circular course around and through the cleaned area depositing the eggs as she passed. After every few passes the male swam over the enlarging patch of eggs and fertilized them. No milt (sperm) could be observed in the water, but even eggs placed one or two inches from the main patch were fertilized. During this activity both fish nipped at the anemone and caused it to retract from the area where the eggs were deposited. The nest was always made in an area covered by the anemone.

The eggs adhered to the rock by means of a short pedestal composed of innumerable small fibers that fanned out over the rock. The yolk contained an oil droplet that may aid the buoyancy of the eggs but did not give them positive buoyancy since they sink if detached from the rock. Each egg could move almost 180 degrees in any direction with water movement, thus the patch of eggs was in constant motion under the careful fanning of the male. The male was clearly in charge of the eggs. He rarely left them for more than a few seconds during the entire period of incubation. The female would give them an occasional mouthing or a quick tail sweep, but did not guard them constantly even though she rarely left the vicinity of the anemone. The male usually positioned himself on topof the eggs and kept them moving with frequent sweeps of his pectoral and caudal fins. He would frequently "mouth" the eggs also, which consisted of positioning himself vertically over the eggs and while maintaining this orientation with quick movements of his fins, he gently bit at them in much the same way as the rock was initially cleaned for spawning. The female also engaged in mouthing the eggs but at more infrequent intervals than the male. This activity continued until the eggs hatched. Although other authors report increased fanning activity the day before the eggs hatch, I did not notice an increase in nest care activities at that time. However, during hatching, which always occurred at night at least several hours after the onset of darkness, the male was constantly active at the nest. This pair spawned 6 times in about 2 months, Nov. 3, Nov. 14, Nov. 30, Dec. 11, Dec. 24, and Jan. 6 were the dates of spawning. Behavior was similar during all spawns and number of eggs spawned varied from an estimated 500 to 800.

Hatching and Larval Recovery

The problem that caused the greatest limiting factor to the number of fish that were reared was not larval mortality, but recovery of the larvae after hatching. This is primarily a manipulative problem and can be solved through experience. Reports in the literature stated that hatching for most Amphiprion takes place on the night of the seventh day after hatching, and sure enough the eggs from the first batch of eggs looked ready to hatch on the seventh day. The reflective pigment of the eyes was well developed, the mouth parts were formed and the embryo was twitching within the chorion (egg shell) of the egg. Recovery of the larvae after hatching in the breeding aquarium was sure to be a struggle and not a positive method of recovery, so that about 75% of the eggs were carefully removed from the rock without disturbing the anemone and with minimal disturbance to the adults. The male resumed care of the remaining eggs when the operation was complete. These eggs, destined to hatch in a few hours (1 thought) were carefully incubated in the prepared larval tanks and I waited anxiously for hatching. It has been said that it's not nice to fool Mother Nature and I was ready to believe it. The eggs did not hatch in the incubating dish or on the rock. Although egg incubation in the hanging dishes was feasible for a few hours, it was not successful for a period of 30 to 48 hours. The eggs did not hatch until the night of the ninth day and by that time I had taken most of the remaining eggs trying to figure out what was happening and had almost given up on them hatching. As a result only 9 larvae were recovered on the day of hatching. Eight of these were reared to the juvenile stage.

The second spawn did not go much better. I waited until the ninth day to take the eggs, and did not take as many off the rock this time. However, a temperature drop in the aquarium of about 3 degrees C caused a delay in development and hatching for several days and the larvae did not appear until the night of the eleventh day after spawning. I also learned that an unattached egg has greater difficulty hatching than an attached one. As superbly illustrated in Dr. Allan's book on page 249, Amphiprion eggs hatch tail first. There is a tendency for a larvae hatching from an unattached egg to retain the egg capsule over the anterior portion of the body and swim about pushing the capsule before it. When this happens the larva soon succumbs to oxygen deprivation. Although it was possible to give the hatching larva an assist with a couple of pins, it was not a practical method of getting good larvae for rearing. An estimated 50 larvae were recovered from this spawn and 43 made it through the larval stage. The majority of these were recovered from the breeding aquarium after hatching by locating and concentrating the larvae with a flashlight and siphoning them from the tank. Undoubtedly some were injured by this treatment, but at least 90% were recovered without injury.

The third spawn hatched in 8 days and recovery was entirely accomplished by siphoning the larvae from the breeding tank after hatching. Many larvae were recovered but still only an estimated one fifth of the entire spawn was captured. Immediately after hatching the larvae swim rapidly and apparently without direction for several minutes, and if during this period they encounter the gravel bottom of the tank or the inside of a shell or other restricted area, they probably never survive to the free swimming stage. The total number taken from the aquarium from this spawn was estimated at 125, and a total of 115 were taken from the larval tank in the post larval stage. Thus recovery after hatching was improving and survival rates remained high. Great things were expected from the next spawns for most of the problems had been identified, if not solved, and confidence was high.

Mother Nature struck again. The fourth, fifth and perhaps the sixth spawns were complete wipe outs. All went well until the fifth day after spawning. At this time I noticed a whitening of the eggs and close examination revealed a granular whiteness of the yolk. The embryo appeared normal, but stunted, and hatching never occurred. When the same thing happened on the fifth spawn, I took some of the infected eggs to a friend At the Florida Department of Natural Resources Marine Research Laboratory to take a look at them through the microscope and see if we could determine the causative agent. We did find some "bugs" in the eggs in large numbers and made a very tentative identification putting them in the microsporida. If such is the case, the infection is probably located in the ovary of the female and may have been introduced with some food item, although it is possible that it entered with the natural sea water or was already in the fish in another developmental stage before she spawned the first time. This type of infection does yield to the SSA treatment (Sterilize and Start Again) so future experimentation must wait until new set ups are prepared. This problem can be avoided, unless it is inherent in all female Amphiprion through careful processing of water and food to prevent introduction.

Larval Rearing

Good success was obtained in rearing the larvae from the above reported spawns. Survival to the post larval stage was estimated in the second and third spawns, but could not have been less than 60% and was probably closer to 80%. The post larval stage was entered when the fish became 1/4 inch long, had developed the orange body color, had formed the white stripe at the nape, and began thigmotaxis (association with a solid object). At this point the fish could be netted and transferred to a grow-out aquarium.

The larval tanks were rather small, 36 gallons, and were designed to provide the proper environment for the newly hatched larvae. Temperature, lighting, salinity, and water quality were all considered in establishing the larval tanks. The design of the tanks also allowed development of water currents and micro-turbulence that aided floatation of food and larvae. The larvae were fed all live foods while in the larval tanks. Specially processed wild plankton and cultures of micro-organisms were the first food and after three days the larvae were large enough to accept brine shrimp and particulate dead and dried foods.

Growth of the larvae was quite fascinating. The disparity of growth rates among larvae from the same spawn that apparently had equal opportunity to feed was quite large. A few of the larvae entered the post larval stage within 5 days, the majority were at this point of development in 8 days and a few took 15 to 18 days before they gained color and abandoned their pelagic mode of life. This great variance in larval growth rate may be more pronounced in nature and may have bearing on distribution of Amphiprion in the Indo-Australian Archipelago- Philippines region. Those larvae that pass quickly through the larval stages would settle near the place of spawning while those with an extended larval life may settle far from their place of origin. There was no apparent difference in viability between the fast and slow growing larvae.

Juvenile Growth

When the majority of the larvae reached the post larval stage, about 10 days after placement in the larval rearing tank, they were removed and placed in an established 20 gallon aquarium to gain in size before being transferred to a 60 gallon grow out tank. At this time they were fed a formula similar to that fed to the adults but processed so that it would break up into many fine particles upon introduction to the tank. Newly hatched brine shrimp were also fed. The fry reached lengths of ½ inch in three weeks and many are about an inch long at an age of 6 weeks. There are no signs of malformations due to malnutrition or any parasitic infections. The fry are very alert and active and even began intraspecific behavioral interactions in the early post larval period. There was one small anemone in the first juvenile tank and the newly introduced post larvae quickly (within two hours) occupied the anemone. I did not observe any period of acclimation by the small fish to the anemone. There was no noticeable avoidance reaction by the fish when it first touched the anemone, however, the post larvae spent up to an hour drifting about the edge of the anemone before entering among the tentacles.

Eight to ten of the larger post larvae established territories on the face of the anemone and guarded this area vigorously. The largest, most dominant fish occupied the center of the anemone. At night these territories disintegrated and at least 50 small clownfish would enter the anemone and nestle among the tentacles. An interesting coloration abnormality occurred in about 10% of the fish. The center stripe, which forms at about 10 to 15 days of age, does not form completely. In some fish only a dorsal saddle is present and in others the bar is incomplete on one or both sides. One fish, a runt, had only one small oval white spot on the right side instead of a mid-body band. There is a tendency for the abbreviated band to develop toward normalcy as the fish ages, but as of this writing none of the markedly brief bands have become completely normal. This unusual banding usually occurs among the fastest growing fish, although there are exceptions. It may be that the period of band formation is somehow disrupted by the rapid larval growth than the tank reared larvae experience.

The black edging of the pelvic fins are the first black areas to develop. The largest juveniles are now displaying the black edging on the caudal and soft dorsal fin. The white band about the caudal peduncle is the last white band to develop and this is usually in evidence at about 15 days.

Many problems remain to be solved (some haven't even been identified) before breeding marine tropical fish becomes routine. However, the successes reported in this brief article indicate that production of large numbers of marine tropical fish is possible. The very basic technology has been developed and given the proper facilities and development time, I feel that many species could be cultured. The basic principles are adaptable to other species, certainly to other Amphiprion, but I am sure many specialized problems will be encountered with various species. The fish from these experimental spawns are now on display at Scott's Highway Aquarium in St. Petersburg, Florida. I hope future articles will be able to recount additional successes and perhaps more details on spawning and rearing procedures.

References

1. Allen, G. B. 1972. Anemonefishes, their classification and biology. T.F.H. Publications, Inc. LTD, Neptune City, N. J. : 1 - 288 pages.
2. Meulengracht-Madsen, J. 1071. Breeding Amphiprion percula. Tropical Fish Hobbyist, Vol. XIX, March 1971: 52-57.
3. Neugegauer, W. 1969. So zuchen wir Korallenfische. Aquarien Macazin. Stuttgart, Dec. 1969: 483-488.
4. Schreiner, W. 1972. Breeding Report Clownfishes. The Marine Aquarist. Vol. 3, No. 31-33.

 

Breeding the Clownfish, Amphiprion ocellaris, postscript

The sixth spawn was also infected with the parasite within the eggs, however, only a portion of the spawn was lost. The eggs were removed from the parents a few hours after spawning and were treated in a solution of sulfathiazole and quinine for three hours. They were then artificially incubated in a methylene blue solution for the entire 8 days of development. The presence of the parasite was noted on the evening of the fourth day of incubation and on the fifth day 330 infected eggs were removed from the rock. Four more were removed the following day and the remaining eggs seemed to develop normally. About 200 eggs remained and hatching took place on the evening of the eighth day. Not all the eggs hatched, about 50 remained on the rock and were expected to hatch the following night. At this point, I made an error. The tank was not adjusted to the larval rearing condition because the remaining eggs were still incubating and about 50% of the newly hatched larvae were lost. Most of the remaining eggs did not hatch anyway, thus all the trouble and loss of larvae was unnecessary .Good experience was gained, however, and about 50 strong larvae resulted from the sixth spawn. Even in larvae 48 hours old, remarkable size variation occurs. Some of the larvae are already 6 mm long and beginning to develop orange coloration while others are still the size of a newly hatched larva.

Corals are the building-blocks of mid-ocean oases of life, and play a key role in promoting biodiversity in every ocean on Earth. A large part of the world’s total biodiversity would be degraded to an extent never experienced in human history if coral reefs were to go extinct (Veron et al. 2009). With increasing threats from global climate change, ocean-acidification, turbidity resulting from deforestation and urban development, eutrophication from agriculture runoff, overharvesting, predation, and disease, it is critical to understand the physiological plasticity of corals. However, corals display unique challenges for physiological examination as a result of photosynthesizing zooxanthellae living symbiotically in tissue.

During the process of photosynthesis within corals, photons of light are absorbed by chloroplasts located in zooxanthellae and the byproducts of fluorescence, heat, and photochemistry are produced. These byproducts are competing pathways for the de-excitation of chlorophyll, which means if heat production is assumed to occur at a constant rate, monitoring fluorescence will allow insight into the yield of photochemistry or energy transfer within the photo-system. For some time now botanists have utilized fluorescence emission to examine the yield and efficiency of photosynthesis in plants, and more recently similar methods are being used to examine photosynthesis occurring within corals. Fluorescence decay or transient, also known as the Kautsky effect, was first described by Kautsky and Hirsch in 1931 and provides crucial information about energy transfer and nutrient production in primary producers.

The Kautsky effect describes a rise in fluorescence resulting from illumination, which decreases with exposure time as more electrons can be converted to photochemical energy. Because fluorescence emission is proportional to absorbed light, and at room temperature most fluorescence (~90%) results from Chl a emission within photosystem II (PSII) (Krause and Weis 1991), quantum yield of photosynthesis can be derived simply by examining and comparing fluorescence levels among different light- or dark-adapted states. Pulse amplitude modulated (PAM) fluorometers are now available for recording fluorescence, which only record after a pulse of light with known intensity and wavelength, permitting recordings in all lighting situations without ambient influences. These units also come with computer software which provides the ability for automatic light sequences to determine different fluorescence variables.

For example, when a dark-adapted sample is subjected to a weak-intensity measuring light there is minimal fluorescence (FO), but an intense, saturating pulse of light will yield maximum fluorescence (FM); variable fluorescence can then be calculated using the difference of maximum and minimum fluorescence (FM-FO=FV). The ratio of maximum to variable fluorescence, known as maximum potential quantum yield (FV/FM), is known to reflect the efficiency of PSII (Krause and Weis 1991) and has been used to determine photosynthetic productivity within plant physiology (Maxwell & Johnson 2000). This ratio is also an accepted indicator of stress in corals (Jones et al. 1999), and represents fluorescence in the absence of photochemical quenching; wherein the process of energy harvest is not limited by electron acceptors. Therefore, FV/FM essentially reveals the maximum potential of light capture occurring within the photo-system at any time.

Temperature stress is known to result in decreases in FV/FM which is reflective of a decrease in photosynthetic efficiency of zooxanthellae (Jones et al. 1999). Many researchers have examined the effect of high temperatures on FV/FM, and rightfully so with the threats of climate change, however few have examined the effects of relatively lower temperatures on zooxanthellae’s photosynthetic performance. With increasing interest in the aquaculture of corals to prevent collection demands from the aquarium trade and for advancing biochemical research, it is necessary to understand the optimal environment for these photosynthesis-dependant organisms. The objectives of this experiment were to

1. judge the efficacy of the JR-PAM fluorometer for underwater photosynthesis research,
2. apply the JR-PAM fluorometer to determine the relationship of FV/FM on coral growth, and
3. to examine the effect of aquaculture temperatures on FV/FM of four species of coral.

A brief summary of fluorescence variables measured with relation to photo-system state and overall physiological importance is presented in Table 1. For a more in-depth description for interpreting fluorescence information see Maxwell and Johnson 2000.

Table 1. Commonly examined variables for analyzing photosynthetic characteristics with notation, application, and physiological information gained. Condition relates to the state of the
plant or algae sample during examination. The application refers to the WinControl3 software program used.

Variable	Notation	Condition	Application	Physiological information
1 PSII-photosystem two of the photosynthesis complex; relates to a pair of chlorophyll molecules which are excited by 680nm light (P680). P680 is involved in photolysis (the splitting of H 2O) and exciting the primary accepting molecule at the start of the electron transport chain. 2 Maxwell and Johnson 2000. 3 Values are relative because they were calculated using WinControl3 software and not actually measured.
Maximum potential quantum yield of PSII1	Fv/FM	Dark acclimated	Induction curve	Reflects the maximum efficiency of PSII, used as a sensitive indicator of plant photosynthetic performance2
Maximum relative electron transport rate3	Max rETR	Light saturated	Rapid light curve	Maximum quantity of electrons transported (μmol electrons m-2·s-1) through the electron transport chain

Methods

Four species of small polyp scleractinian corals: Acropora sp., Montipora digitata, Pavona decussatus, and Seriatopora hystrix, were examined for photosynthetic characteristics and growth during a 12 week experiment. Each species began with a total of 6 individual fragments (n=24), which were allotted two each into three 10-gallon aquariums and mounted on ceramic plugs (n=16) or acrylic rods (n=8) depending on which tank the sample was in. Coral fragments were arranged in an identical orientation within each aquarium using frag-racks positioned 16cm below the surface with VorTech MP10 wave-makers creating a horizontal gyre. The tanks were illuminated using a 50/50 mixture of 6500K (Daylight) and 420nm (Actinic) T5 fluorescent lights located 23cm above the surface of the water. These aquariums were part of a 200 gallon re-circulating system maintained in the aquarium lab of Alaska Pacific University

Temperature and System Parameters

The temperature for the above-mentioned system was monitored by an YSI controller with the ability to detect a 0.2°C temperature differential; this monitored the function of two controllers (one for the heater, and one for the chiller) which each regulate within a 1°C range. Each aquarium was equipped with a Coralife digital thermometer to measure temperature within each tank. The system’s temperature was systematically increased by 2°C every 3 weeks from 22 to 28°C to sample a range of typical aqua-culturing temperatures. Throughout each treatment, manual tests were performed routinely to monitor calcium, alkalinity, pH, NO2, NO3, and ammonium in addition to temperature. Alkalinity, calcium, and salinity were maintained using SeaChem raises alkalinity-, raises calcium-additives, and Red Sea aquarium salt, respectively.

Testing the JR-PAM

All fluorescence measurements were obtained using the Junior- or JR-PAM (Walz, Effeltrich, Germany), equipped with a single 100cm plastic fiber, 1.5mm in diameter. It should be noted that the photosynthetically active radiation (PAR), referred to here as photosynthetic photon flux density (PFD), for all data were not corrected for length of fiber optic used. Values represent PFD emitted using a 400cm fiber, which may result in a misrepresentation for values for PFD. Nonetheless, the photosynthetic information gained remains proportional. All data was analyzed using PAM WinControl-3 software, using a blue (450nm) LED for measuring light, actinic light and saturating pulses.

To determine the precision of the JR-PAM the amount of distortion occurring with distance and medium (air or water) was examined. The fiber optic tip of the fluorometer was adjusted using a small ruler and the fluorescence standard foil provided with the fluorometer was used as a constant. The fiber optic tip was adjusted accordingly using a leaf clip provided with the unit, which orientates the tip 60° from the sample. Signal was recorded from 1-10mm in 1mm increments. After distance adjustments were made the signal was tested in both air and water.

To determine the efficacy of the JR-PAM fluorometer for examining aquatic, photosynthetic organisms multiple known photosynthesis-dependent organisms were tested. Since all organisms containing chlorophyll display characteristic fluorescence decay upon illumination, fluorescence was simply monitored for a brief period of time during the onset of illumination within algae (coralline and filimentous), jellyfish (Cassiopeia xamachana), and multiple coral species to determine if the JR-PAM could detect a typical Kautsky fluorescence transient underwater.

Growth Measurements

The change in mass of each coral fragment was monitored using a digital scale accurate to the .001 gram. Each fragment was fully cleaned prior to weighing by brushing off the plug with a tooth brush to rid the measurements of accumulated algal mass. Samples were suspended out of water for approximately 10 seconds to drip dry, and any excess water droplets were removed with a light shaking. Samples were then weighed in a known amount of water, and the combined weight of both coral and plug was measured. Mass was recorded at the beginning and end of each 3 week temperature treatment and change in mass was calculated.

Measurements of Chlorophyll Fluorescense

Rapid light curves (RLCs) were used to determine maximum and relative electron transport rate (rETR), and dark-adapted induction curves were used to examine maximum quantum yield (FV/FM). RLCs consisted of exposing light adapted coral samples to increasing photon flux densities (PFD) from 66-820 µmol photons m-2·s-1 to fully saturate and in most cases, over-saturate the photo-system. Induction curves were used to determine minimal fluorescence (FO) and maximum fluorescence (FM), which were required for the determination of maximum potential quantum yield (FM-FO/FM) or (FV/FM). Induction curves were recorded at night, with samples having ≥30 minutes of acclimation to darkness (0 µmol photons m-2·s-1). All recordings were taken ~1mm from the sample’s cenosarc, and the coral was lightly touched to retract polyps in an effort to account for known variations in photosynthetic activity between the two parts of the corals’ external anatomy (Ralph et al. 2002).

Results

Culturing Conditions

Each sample was maintained under a PFD ranging from 97 to 223 µmol photons m-2·s-1 based on location in tank, resulting from the distribution of electric bulbs (figure 1). Mean intensity of samples’ local light habitat was 161 ± 36 µmol photons m-2·s-1. Average temperature per designated treatment was maintained, at most, within 0.7°C of intended set-point (Table 2). Water parameters (pH, calcium, nitrates, nitrites, and ammonia) did not significantly vary across treatments, with the exception of alkalinity (F=3.7, df=3, p=.02) (figure 2).

Table 2. Results from routine water quality tests displayed by temperature treatment.

Treatment	Temperature (°C)	Salinity (ppt)	pH	Alkalinity (meq/L)	Calcium (mg/L)
- Values +/- standard deviation. - Nitrates, nitrites, and ammonia were also tested routinely, but were undetectable throughout treatments.
1	22 ± 0.2	33 ± 1.0	8.3 ± .02	3.5 ± 0.4	416 ± 30
2	24 ± 0.6	33 ± 1.0	8.3 ± .01	3.0 ± 0.5	411 ± 11
3	26 ± 0.7	33 ± 0.5	8.3 ± .02	2.7 ± 0.3	402 ± 14
4	28 ± 0.2	33 ± 0.8	8.3 ± .05	2.8 ± 0.4	432 ± 30

Efficacy of the JR-PAM fluorometer

Applying the terrestrial JR-PAM fluorometer underwater resulted in an intensification of signal (figure 3). Figure 3 also displays the effect distance has on signal, which declines exponentially in either medium with distance from 1-10 mm of the fiber optic sensor’s end. Also, all photosynthetic, aquatic organisms examined with the JR-PAM in situ clearly displayed the Kautsky effect of photosynthesis (figure 4).

Relating fluorescence to productivity

There was no correlation between FV/FM and change in mass for any of the species examined. The majority of corals increased in mass throughout the experiment (figure 5), however S.hystrix experienced substantial decline in mass and ultimately all six samples representing the species died over the course of the experiment (figure 5d). Coral growth was also not significantly influenced by maximum rETR or temperature within this experiment.

Effect of temperature on fluorescence

Both maximum rETR and FV/FM varied significantly among the four temperature treatments and a consistent, reduction of FV/FM was observed among all species when exposed to the lower-end of temperature range (figure 6). The extent to which FV/FM decreased varied among the four species examined. Pavona decussatus displayed the most variable FV/FM with a dramatic reduction in FV/FM during the 22°C treatment (F=8.7, df=3, p=.001; ANOVA). A similar effect was seen with M.digitata (F=5.0, df=3, p=0.010) and S.hystrix (F=12.9, df=3, p=.032), though small sample size for S.hystrix should be considered when interpreting results. Acropora sp. displayed a similar, significant variance in FV/FM among the temperature treatments (F=3.7, df=3, p=.030), but unlike the other three species the largest decrease occurred at 28°C (figure 6). Lower temperatures also resulted in a significant decrease in maximum rETR within P.decussatus (F=7.2, df=3, p=.002), however Acropora sp., M.digitata, and S.hystrix did not display a similar variance between treatments (figure 7).

When RLCs from all species are examined collectively, there is clearly a significant effect on the shape of the curve with regard to temperature treatments (figure 8). The rETR of corals was significantly higher during exposure to relatively higher intensities of PFD, but the relationship was significantly affected by temperature. Again, the highest values for rETR occurred within the 26°C treatment.

Discussion

The aquaculture of corals has seen many technological advances in recent years. New ways of moving water through systems using synchronous wave-makers are now available to simulate tidal fluxes and diurnal variations in flow similar to that experienced in the natural environment, and advances in controlling and dosing for water parameters allows long-term stability of systems, opposed to daily variations in temperature, salinity, and pH regularly seen in earlier aquaria. Lighting has also become more intense and efficient, and may finally be enough (in most cases more than enough) to maintain even the most light-dependant organisms. Though this technology has been the source of advancement in the aquaculture of corals, a lag persists in photo-physical examination to ultimately judge the ideal environment for a given species of coral.

Though the underlying concepts of fluorescence and quenching in photosynthesis remain complex and have generated some debate (Maxwell and Johnson 2000), the application of PAM fluorometry itself is straightforward. The technique has been widely accepted and utilized in photosynthesis studies. By following simple protocol, one can accurately gage the efficiency of a photosynthetic organism, but more importantly, gain an understanding of what exactly is affecting the photo-system. Laboratory experiments make controlling the state of photosynthesis (light v. dark) very simple, and can provide crucial information for understanding the effects an environment may have on coral and other photosynthetic organisms.

Junior-PAM fluorometer for aquatic use

The JR-PAM fluorometer provided rapid results. Controls and functioning are simple, and the unit allows inexperienced users the opportunity to record very in-depth, physiological information. The ease of recording does not reflect the ease of interpreting the measurements however, and the chemical reactions of photosynthesis should be well understood in order to properly apply any fluorometer; see Maxwell & Johnson 2000 for further details. When the fluorometer was applied to aquatic, photosynthesizing organisms, the Kautsky effect was clearly visible across all photosynthetic phyla examined (Cassiopeia xamachana, Tridacna sp.,and coralline and macroalgae algae species), which is accepted within this experiment as evidence that the JR-PAM is applicable for examining biological-fluorescence underwater.

If cost is of concern, the JR-PAM is perhaps the least expensive method of examining photosynthesis in aquatic organisms. Costing around $3,000 per unit, the JR-PAM is ~$17,000 less than the only advertised waterproof model the DIVING-PAM. The JR-PAM is not fully submersible, unlike the DIVING-PAM, however the fiber optic sensor is. The application of the JR-PAM is restricted by fiber optic length and dependent on a computer for power, but the unit still remains a very useful and cost-friendly tool for examining photosynthesis within the laboratory environment.

Coral productivity

The growth and productivity of photosynthesizing corals is dependent on a number of environmental variables. Though an attempt was made to maintain water parameters consistent through the 12 week experiment, an untimely drop in alkalinity resulted from a precipitation event occurring within the saltwater mix-tank used for water changes after the first temperature treatment (22°C). While growth in this experiment was apparently not related to FV/FM, it should be noted that alkalinity and temperature co-varied throughout treatments. Variation of alkalinity within this experiment, though remaining within recommended levels, should be considered when interpreting results.

Effect of aquaculture temperature

A large and much generalized range of temperatures are recommended for maintaining corals in aquaria, and rightfully so considering their extensive range in nature. However, in order to maximize production of corals, minimize the costs of operations (ex. heating and lighting), and ultimately provide an optimal environment for corals in captivity we need to properly assess their health. Given that FV/FM is a good indicator of stress in corals, PAM fluorometry seems appropriate for finding the conditions in which any given species thrives.

The organisms in this experiment revealed optimum temperatures for four species held in the Alaska Pacific University lab, from which we can see that what is best for one species may not be true for another held in the same system. For example, as Pavona decussatus and Montipora digitata appear to thrive at a temperature of 28°C, Acropora sp. displays a significant reduction in FV/FM indicating it would be better maintained in a slightly cooler environment. From information like this institutions can run aquariums according to most efficient temperature and lighting, and know the effect it will have on inhabitants. Also, aquariums can be arranged with corals that thrive at similar temperatures to ensure maximal production in aquaculture, which would ultimately reduce the demand for collection of wild corals.

Acknowledgments

I sincerely thank Professor David Scheel of Alaska Pacific University for his continued support and dedication to students, the Alaska Pacific University’s environmental science department and aquarium lab (as part of the BP science center) for providing a suitable environment for test subjects and JR-PAM fluorometer, and Alaska Coral Fanatics (Anchorage, AK) for providing corals for fragmentation. I would also like to acknowledge the At-sea Processors Association for funding of additional supplies.

References

1. Jones, R.J., Kildea, T., and Hoegh-Guldberg, O. 1999. PAM chlorophyll fluorometry: a new in situ technique for stress assessment in scleractinian corals, used to examine the effects of cyanide from cyanide fishing. Marine pollution bulletin. Volume: 38, No. 10, pp. 864-874.
2. Krause, G.H. and Weis, E. 1991. Chlorophyll fluorescence and photosynthesis: The basics. Annual review of plant physiology and plant molecular biology. Volume : 42, p.313-317.
3. Maxwell, K. and Johnson, G.N. 2000. Chlorophyll fluorescence – a practical guide. Journal of Experimental Botany, Vol. 51, No. 345, p. 659-668.
4. Ralph, P.J., Gademann, R., Larkum, A.W.D., Kuhl, M. 2002. Spatial heterogeneity in active chlorophyll fluorescence and PSII activity of coral tissues. Marine Biology. 141: 639–646.
5. Veron, J.E.N., Hoegh-Guldberg, O., Lenton, T.M., Lough, J.M., Obura, D.O., Pearce-Kelly, P., Sheppard, C.R.C., Spalding, M., Stafford-Smith, M.G., and Rogers, A.D. 2009. The coral reef crisis: The critical importance of <350 ppm CO2. Marine Pollution Bulletin 58. p.1428-1436.

In my 50 years as a marine biologist and culturist of marine fish (and a few invertebrates), I have written a number of books, articles, and scientific papers. Some of these are both historically interesting and still have descriptive value for the culture of various species. I plan to revisit a few of these in Advanced Aquarist from time to time in a series titled "The Way We Were".

This is an article from the dawn of marine fish culture. It appeared in the February 1975 issue of The Marine Aquarist. It was titled "Propagating the Atlantic Neon Goby" and it described the first successful efforts at mass culture of the neon goby, Elacatinus oceanops formerly Gobiosoma oceanops. The photos are in black and white, the only color for small magazines back in those days, when color was very expensive, was on the cover. An inside color photo was very rare. The photos in my original article were good for the time but are now only of historical interest. There is a new thing called the internet, I believe, that has amazing and wonderful photos of gobies and the entire process of breeding them that I could not even imagine back in the 70s, so now the information on breeding this goby is available at the click of a mouse (a phrase which would have a very different meaning back in the 70s).

I selected the neon goby as the second species to breed after the false clownfish, Amprhipion ocellaris, because of its great popularity, importance and value as a parasite picker in nature and in captivity, and its interesting and easily observable behavior in aquariums. It turned out to be relatively easy to breed, its small size, compatibility of mated pairs, frequency of spawning, and the ability of the larvae to begin feeding on rotifers made it a very good species for culture. The only drawback, especially back in the mid 70s, was the low price. Times have changed but popularity of the neon goby, an excellent species for reefs tanks and fish only tanks, is still very strong. We spawned and reared several other species of gobies and were most successful with the sharknose goby, Elacatinus evelynae, and the Christmas or Greenbanded goby, Gobiosoma multifasciatum. At that time only the neon goby was popular enough to support commercial production. The greenbanded goby was also a bit more difficult to rear because the larvae required a bit smaller rotifer than was available at that time and so early feeding depended on providing only the smallest of rotifers, which was a bit problematic.

Even now, as then, the popularity of a species with consideration of availability and price of wild caught specimens, determines whether or not commercial production at any level is worth the effort and expense of breeding. But fortunately, these gobys and a number of others are now captive bred and available to aquarists.

Published February 1975 issue of The Marine Aquarist

---

Propagating the Atlantic Neon Goby

The neon goby, Gobiosoma oceanops, is one of the largest species of the genus and probably the most common go by in marine aquariums. It is a cleaner species and even though of small size (2 to 3 inches as adults) the neon goby does well in a community tank. It will engage in cleaning behavior with Pacific as well as Atlantic marine fishes. We often keep them with large clownfish and frequently observe symbiotic cleaning behavior. The clownfish assumes a head up position and slowly flutters its fins while the neon goby swims with rapid, jerky movements over the clownfish's sides and fins looking for parasites. A quick shake and resumption of normal swimming posture by the clownfish breaks the cleaning pattern and sends the goby on its way. The neon and its close relative, the shark-nosed or gold lined goby, Gobiosoma evelynae, make an interesting and colorful addition to any marine tank and even benefit the occupants through their parasite cleaning behavior.

As the neon gobies mature, they begin to pair for mating and can cause great problems In the close confines of an aquarium. Once a pair is established they forcibly reject any others of their species and even a 100-gallon tank is not big enough for three neon gobies. However, if six to eight or more gobies are present in a tank, pairing and aggressive behavior is muted, and aside from a few minor squabbles, the fish can co-exist.

Once a pair is identified, they can be easily induced to spawn by providing a suitable spawning habitat. The neons, like other gobies we have worked with, are secretive spawners. They select an overturned shell, small pipe or inside of an aquarium ornament as a spawning site. Spawning has always occurred on the underside of a surface and the attached eggs extend downward into a restricted cavity. Spawning usually takes place in the early morning hours, although I have observed it to occur in afternoon and early evening hours as well. It is difficult to observe the actual deposition of eggs because of the secretive spawning site, but there seems to be several periods of egg deposition by the female followed by fertilization by the male. Both sexes twitch and wiggle side by side under the shell during the spawning process. The female leaves the site after spawning and only infrequently visits the eggs during the incubation period.

The male spends much time caring for the eggs during incubation by moving his body and fins over the egg patch at frequent intervals. He readily leaves the eggs for short periods to feed and explore, but soon returns and rests upside down underneath the egg mass. The female often rests above the shell at the entrance to the nest cavity or cruises about the general vicinity. The shell containing the spawn can be removed for examination and replaced without any harm to the eggs or disruption of the male's incubation behavior. The male cares for the eggs throughout the incubation period, which, depending upon the temperature, may be between 6 to 8 days.

A large female at the height of reproductive activity may lay 500 to 600 eggs, but the usual spawn size is about 250 eggs. The egg capsule is about 2 mm long and 1 mm in diameter and is completely transparent. The entire development of the embryo can be observed through the chorion, or egg case. The attachment of the egg consists of a mass of fiberous threads extending from the base of the egg capsule to a sticky pad that adheres to the substrate. The eggs are placed very close to each other and the newly laid spawn has the appearance of-an undulating patch of clear globules. After the eyes become pigmented, the patch takes on a silvery appearance. The embryo begins development with the head pointed towards the base or attached end of the egg capsule. The embryo turns around in the egg capsule on about the third day of development and completes incubation with the head developing within the stelate, distal end of the capsule.

Feddern (1967) and Valenti (1972) both describe embryonic development of neon goby larvae and these papers should be consulted for technical details on larval development. Valenti states that larvae that do not reverse in the egg capsule at 50 hours, but complete development with the head at the base of the capsule, do not hatch. Our experience has shown that hatching takes place regardless of the position of the larvae. At hatching, the capsule ruptures by the head of the larvae wherever it happens to be positioned, and the larvae forces itself out the opening. I have never observed a larvae fail to hatch because of a reversed position.

In one instance that I was fortunate enough to observe through the microscope, a malformed goby larvae was completely encased in a normal egg capsule. The larvae appeared to be missing a portion of the notochord and the body wall about the gut was completely absent leaving the gut and yolk sac exposed within the egg capsule. This condition was observed shortly after hatching of the spawn and this larvae had eroded the egg capsule in the vicinity of the gut instead of at the head. These observations indicate that hatching occurs as a result of the release of some substance, probably a proteolytic enzyme, originating in the vicinity of the gut and released at the mouth that breaks down the egg capsule in the area of the head.

The larvae are quite small (4 mm long) upon hatching and usually carry a residual yolk. Feeding usually begins about 12 hours after hatching, depending upon the state of development at the time of hatching. Small living organisms are required as a first food. The larval stage of the neon goby is rather prolonged. First metamorphosis into the adult coloration and behavior pattern occurs at about 18 to 20 days, although it may extend to 40 days under adverse conditions. The larvae are reared under a carefully simulated pelagic environment.

The early juveniles take up a benthic mode of life shortly after the first color appears on the transparent larvae. A faint blackening of the sides quickly becomes a bright sliver of electric blue and the cupped pelvic fins attach the early juvenile to the tank substrate. Growth is rapid after this point in development is attained and sub-adult size is reached within 3 months. The young gobies can be paired at this time although first spawning is still 2 or 3 months in the future.

We have spawned about ten pairs of tank reared gobies to date and have noted no obvious difference between wild and tank reared fish, either in morphology or reproductive success. Growth continues after spawning commences and when the fish are ten months to a year old, they are full adult size and are at the height of reproductive activity. Spawning takes place every 10 to 12 days depending on temperature, and we have had pairs spawning in every month of the year. The spawning period in nature is February to April (Feddern); however, we have been able to spawn the gobies every month of the year in the laboratory.

References

1. Feddern, H.A.1967. "Larval Development of the Neon Goby, Elacatinus oceanops, in Florida,' Bulletin of Marine Science, Vol. 17, No.2, pp. 367-375.
2. Valenti, R.j .1972. "The Embryology of the Neon Goby, Gobiosoma oceanops," Copeia, 1972, No.3, pp. 477-482.

The CV Dinar aquaculture facility, which is more easily called a farm, is located on the northeast coast of Bali, not too far east of Tulamben. It's also around 6 degrees south of the equator meaning the water's warm and there's plenty of sun year round, which gives rise to wonderful coral reefs. And, needless to say, the diving in spots around the island are absolutely incredible.

Diving in many areas can be deceptive though, because you typically get to see the best, healthiest areas, while other locations may be in bad shape. Most everyone has heard of the spectre of coral bleaching that has affected so many reefs around the world, and then there are the added insults of pollution, over-collecting, dynamite fishing, shipwrecks, etc. that have all taken their toll on both corals and giant clams, as well. These are some of the reasons that many businesses are aquaculturing a variety of organisms for the aquarium hobby now, and why other organizations are doing the same for the purpose of restocking natural areas. Farming clams has also helped to satisfy the demand for giant clams as food in Asian countries, too.

Anyway, after contacting the farm, I was picked up by Aspari Rachman, the facility manager, and taken for a full tour of the whole place. It isn't particularly big, but they certainly squeeze a lot of livestock into what they have. There are about 30 large concrete grow-out and holding tanks, and quite a few other concrete and acrylic tanks used for various other purposes, too. They have an on on-site lab, and various other buildings, one of which is used to raise their own phytoplankton used to feed infant clams, and zooxanthellae for them, too.

They have a huge water intake system at the shore, which allows them to pump water directly from the sea, after which it's run through a series of baffles that contain progressively smaller gravels and sands that act as filters. This water is then pumped through the tanks, making it easy to maintain high water quality. And, in the case of infant clams, the water is also run through micron filters to remove any sorts of parasites, too. Thus, there is a constant turnover of fresh, clean seawater in the systems, with no other sorts of filtration. There's also no need for additional lighting either, as there's plenty of sunlight for free. In fact, the sun does such a good job that they have shade cloth over all the tanks to cut down the amount of light the inhabitants get, and to help keep leaves and such out of the tanks, too.

The Corals

They were growing several types of stony coral at the farm, primarily being Acropora and Seriatopora, and also had plenty of the soft/leather corals Sarcophyton and Sinularia, as well as a few others. All of these were attached to small pieces of rock (which I'll talk about below), and had started out as frags/cuttings from other larger specimens. All of these corals can easily be cut or broken into pieces, and the pieces will live and grow into new specimens. So, they do the same thing that's regularly done by hobbyists and businesses here, but on a much larger scale, and with one big difference. Once the frags/cuttings are made and are attached to a base, they're put in the sea instead of being kept in a tank for weeks or months.

The farm has numerous metal cages on hand, and the corals are placed in these where they can be kept together and get some protection from wave activity and predators, too. The cages are carried maybe 100 yards out off the beach and placed on the bottom in about 20 feet of water. Then they sit for quite a while, sometimes several months. Of course, when you're not paying for salt, additives, and lighting the amount of time they sit is determined by how fast they grow to the size the farm likes rather than moving them to market as soon as they get big enough for someone to want to buy them - and the farm likes them pretty big.

Once the corals have grown large enough to satisfy the farmers, the cages are pulled and the specimens are placed in holding tanks on land. Then they're bagged up and shipped out.

The Clams

The farm also raises all six species of giant clam commonly seen for sale over here, being Tridacna crocea, T. maxima, T. derasa, T. squamosa, T. gigas, and Hippopus hippopus. And, they raise H. porcellanus too, which I was looking forward to finally seeing. These are very difficult to find for sale, and haven't been seen in the U.S. market for many years as best as I know. I bought one about four years ago, and the supplier said it was the first they'd ever seen after being in the clam-selling business for over seven years. Despite having at least a couple hundred mature specimens on hand, they told me that none were sent to the U.S. Anyway, while the corals are relatively easy to deal with, the clams take a lot more work, as they obviously can't be cut up to make more.

Giant clams are spawners, meaning when the time comes, individuals can spew out huge numbers of sperm and eggs into the water where some will meet the sperm and eggs of other clams. All of them are hermaphrodites when they are mature, so each can produce both sperm and eggs, too.

Well, on the farm they can be artificially enticed into spawning by injecting them with a small dose of the hormone serotonin. Once the hormone is injected into a clam's gonads, it will begin to spew clouds of sperm at first and then the eggs come after the sperm is depleted. So, in order to keep the clams from self-fertilizing (which makes for bad genetics), a clam is allowed to pump out the sperm and is then moved to another tank where the eggs can be released. Then the sperm can be collected from the water and intentionally mixed with the eggs from another clam. This sort of thing can be done with multiple clams, assuring that they have a good mixing of genetic material, which produces healthier clams.

After all of this, the eggs start to divide and grow, and soon become swimming larvae. At this stage they still do not have any symbiotic zooxanthellae though, as it's not passed from the parents to the offspring. Coral fragments already contain some, of course, but the clam larvae have to get their own complement of the algae by filtering some from the water.

So, the farmers grow zooxanthellae on site using a method they developed themselves, and add a little to the tanks that the larvae are in. The larvae then eat and hold onto it and allow it to reproduce inside their tissues. Other types of phytoplankton are also added, which the infant clams can also eat and used for food. Oddly enough, no one has figured out how it works, but the clams are able to keep the zooxanthellae alive for themselves, while simultaneously digesting other sorts of algae.

Anyway, the swimming larvae drop to the bottom after a short period of time and begin to undergo a metamorphosis, losing the ability to swim and taking on a new life upon the bottom. The farmers continue to add phytoplankton for two months, and they also begin adding nitrogen-based chemicals, too. Giant clams need a source of nitrogen and can extract it directly from seawater in the form of ammonia and nitrate, but giving them extra amounts can increase their growth rates significantly. So, things like ammonium nitrate (fertilizer) or sodium nitrate can be added to help speed things up.

Then, after sitting and growing in a holding tank, typically for more than a year, the clams are big enough to be placed in cages and put out to sea with the corals. At this time they still may be only an inch or two in length depending on the species, so many have a lot of growing to do before they can be sold as good-sized specimens. Some farms do sell clams while still at such a small size, but CV Dinar doesn't. I didn't ask why, but from what I understand, the small clams suffer significantly higher mortality rates, while bigger clams can handle shipping stresses much better.

Once in the cages, the clams are left in place for as long as three more years. So, you can see that this can be a slow process that takes a lot of patience. The timing of collection is primarily due to the species, I should also add, as some clams like T. gigas and T. derasa can potentially grow many times faster than other clams, like T. crocea.

Regardless, the farmers are constantly putting out hundreds of clams at a time, and everything ends up running like a conveyor belt. Small ones go in and big ones come out. The seafloor has plenty of space for cages too, so using them and keeping them in the sea means that there can be thousands of clams out at a time while the facility only needs enough room to hold the juvenile clams and those that are ready for export. Everything in between takes up no space in the tanks.

And Live Rock Too

By the way, the rock they need for the bases is made by hand on site by using local stone and cement, and they make lots of artificial live rock ranging from fist-size up to large mounds a couple of feet tall, too. Basically they just lay out some palm leaves on the ground and pile up the concrete-like mix to the desired size. The cement is allowed time to harden, and then the pieces are put in piles in the sea for several months. So, it becomes fully cured there, and also gets some stuff growing on it. In the end, much of it looks as good as much of the live rock coming from the Pacific and is sold as aquacultured live rock. But, they also hold onto some of it to use in re-stocking efforts.

Restocking Reefs

Again, many reefs are having problems, and the farm has been directed to help out by the Indonesian government. According to Aspari, they are allowed to operate the farm and export livestock as long as 10% of everything they grow is used to help the local reefs. So, they take some of the larger pieces of rock they produce and mount various corals and clams to them, then place them in areas that have been damaged in various ways. They were also trying to start new reefs in some spots, too. All in all, they're doing a great job and helping the hobby and the reefs.

The staff at the CV Dinar facility was exceptionally nice and very knowledgeable, but I have no experience with them on the exporting and business end. This article is by no means an advertisement for them, and is strictly for education.

Sources for more information on clam farming, which can be found online:

1. Ellis, S. 2000. Nursery and Growout Techniques for Giant Clams (Bivalvia: Tridacnidae). Center for Tropical and Subtropical Aquaculture Publication 143.
2. Ellis, S. 1998. Spawning and Early Larval Rearing of Giant Clams. Center for Tropical and Subtropical Aquaculture Publication 130.

I suppose most serious hobbyists will watch a program concerning corals reefs on the Discovery Channel or Animal Planet (or other) television channels. With the cost of big-screen televisions rapidly falling in price and their use becoming commonplace, viewing these video essays on a giant screen can be spectacular. If you're a coral afficianado such as me, you'll especially enjoy those shows dealing with the invertebrates of coral reefs. Some of the most astounding videos can be of coral spawning. We the extreme close-up video of corals extruding their egg bundles to the shallow seas during early evening. It would be easy to believe that all corals reproduce in this manner but such is not the case. One such case is the coral Porites lutea in Hawaii.

Facts about Porites lutea (Milne-Edwards and Haime, 1860):

Phylum: Cnidaria
Class: Anthozoa
Subclass: Hexacorallia
Order: Scleractinia
Suborder: Fungiina
Family: Poritidae
Genus: Porites
Species: lutea

Porites lutea (formerly P. evermanni) is a common coral in Hawai'i and throughout the Indo-Pacific Ocean. These animals are mostly often found in water up to 6 meters (20 feet) in depth. Coloration can be brown, yellow-brown, gray, sometimes with purple highlights and less often entirely purple. It is never yellow-green like P. lobata (Fenner, 2005). Porites colonies are among the longest living animals known where some are hundreds of years of age.

Kahalu'u Beach Park on the west coast of the Big Island of Hawai'i provides a perfect spot to easily observe P. lutea and other coral colonies. A mysterious rock wall (Hawaiian legend suggests the wall was built by the Menehunes - a race of secretive, tiny people) shelters the bay from intense wave action and provides calmer waters preferred by P. lutea and a rapidly aging coral observer (me). Hence Kahalu'u is also a favorite spot to document coral spawning activities. Members of the ReefWatchers group have observed spawnings of Pocillopora meandrina, P. eydouxi, and Leptoseris bewickensis there.

The Department of Land and Natural Resources (DLNR) Division of Aquatic Resources monitoring team members provided some details of P. lutea's reproductive behavior (Sara Peck, personal communication). Evidence of a spawning was observed on July 9^th, 2009, sometime between noon and 1400 hours, while DLNR's Dr. Bill Walsh and Brent Camen were monitoring a transect line off the west coast of the Big Island Of Hawai'i. They observed a large cinnamon colored cloud of spawn surrounding and obscuring a P. lutea colony estimated to be some 9 meters (30 feet) across.

Would these corals spawn again the next day? Intrigued, I cancelled the plans I had and prepared to photographically document the daytime spawning of this species.

I had hoped to be in the water at noon on July 10^th, but as luck would have it, I would not get wet until about 1230 hours. The day was one straight out of a travel brochure - a blue sky above the palm trees, plenty of sun, and calm warm water. Snorkeling across the reef flat to the coral bommies, I noticed the water seemed a bit turbid, and within five minutes of entering the water I would know why. There was a mass spawning event of P. lutea occurring. The first colony (out of 7) I observed was apparently finishing its spawning, as I saw only one slow discharge of sperm. I hurriedly and clumsily opened my dive bag to remove a kitchen baster and a small plastic bottle and collected a spawn sample. I began to look for further evidence of spawning, and didn't have to go far - I entered a shallow depression filled with P. lutea - and they were all spawning (this almost mono-specific stand of Porites is in the introductory photo which was taken after the spawning event was over). Things were getting hectic. I had the baster and bottle in one hand, and the underwater camera in the other. Get a photo - take a sample. I needed some help. I surfaced and hailed a nearby snorkeler. I rapidly told him of the situation, and asked if he would help me. He nodded his head, and I began to take more photos and samples. I never saw that snorkeler again and can only suppose that swimming in a sea full of coral gametes held absolutely no appeal to him.

The best show was still to come. Even through the water's reduced visibility (estimated to have dropped to only 6 meters, or ~20 feet from a normal 16 meters - ~50 feet), I could see the outline of a massive P. lutea surrounded by an underwater fog of gametes (see Figure 2). I watched in awe as this coral slowly released gametes for at least 20 minutes (some colonies were observed spawning for as much as 30 minutes). More photos and samples were taken. After an hour, the spawnings stopped, but I stayed in the water for another 30 minutes in hopes of seeing female colonies releasing eggs (quick looks at my bottle with composited spawning samples had revealed no eggs during this very hectic hour). I reluctantly left the water as the bay's normal clarity returned, suggesting the event was over.

Once in the lab, I made my notes and a microscopic exam of the spawn sample. Unfortunately, I could not spot any eggs either visually or microscopically, and after examining quite a few detritus particles, I abandoned my search.

Combining two observations, this is what we know about daytime spawnings of Porites lutea.

Spawning Event of July 9, 2009 (Observers: Walsh and DLNR monitoring team)

• Though not directly observed, a large female colony at a depth of 10 meters (30 feet) was obscured by a cloud of gametes (eggs).
• The cloud of eggs was cinnamon in color*, and 'sticky', clinging to wetsuits.
• Spawning occurred between noon and 1400 hours.

* Interestingly, at least some P. lutea eggs are known to contain zooxanthellae when released during spawning (symbionts are obtained from the parent colony through a process known as vertical transmission). This might account for the reported brownish coloration. However, see comments on the possibility of P. lutea being a gonochoric brooder below.

Spawning Event of July 10, 2009 (Observer: Riddle)

• Spawnings of 7 colonies were observed
• Colonies were apparently all males
• Slow continuous release of sperm appearing as 'white smoke' and lasting up to 30 minutes
• Entire spawning lasted at least one hour (12:35 - 13:35 hours)
• These spawnings occurred 2 and 3 days after full moon and on a rising tide (approximately 2.25 and 1.5 hours after the morning low tide, 7/9/09 and 7/10/09, respectively).
• Sexuality: Gonochoric (separate male and female colonies)
• Reproductive Mode: Broadcast spawner (sperm)*; no egg release observed
• Sexual Maturity Size: Smallest spawning colony was 450 cm² (roughly 72 square inches - 6x12 inches), but maturity could quite possibly be even smaller.
• No eggs were collected; however previous reports state eggs contain zooxanthellae (Neves, 1998).

* Parthenogenesis and brooding have also been reported as a possible reproductive mode in P. lutea (Fadallah, 1983).

Our observations are at odds with that reported by Kenyon (1995). Histological examinations of 3 P. lutea specimens gathered in May in Palau (7N, 138E) found no eggs.

Does P. lutea spawn earlier (or later) than those in Hawai'i, or is this a case of mistaken identity? Which leads us to our next topic.

Taxonomy

Corals are generally difficult to identify to the species level, and the specimens of genus Porites are particularly so. Porites lutea in Hawai'i were formerly called P. evermanni (thought to be endemic to Hawai'i). However, Forsman et al. (2009) report samples of Hawaiian P. evermanni are genetically indistinguishable and similar in corallite characteristics from a Panamanian Porites. In addition, it was identical genetically to a branching morph of P. annae from American Samoa.

Plasticity of coral skeletons due to any number of pressures creates the 'coral species problem' that will likely take some time to resolve.

We used the identification of P. lutea suggested by Fenner (2005), where gross morphology of the skeleton is used, as well as color. His observations and recommendations allowed us to successfully locate spawning Porites colonies within Kahalu'u Bay. A later conversation with Dr. Paul Jokiel validated Fenner's identification methods.

We should note that the Porites species closely resembling P. lutea is P. lobata. Information available to us states that Hawaiian P. lobata spawns during July and August evenings, two to four nights after the full moon and at 2100-2300 hours, or 0100-0300 hours (Gulko, 1995).

In Closing

To our knowledge, this is the first report of P. lutea's daytime spawning as early as July in Hawaiian waters. There is a report of Hawaiian P. evermanni reproducing in August and September just after the full moon (Hunter and Hodgson, unpublished, in Neves, 1998; also in Richmond and Hunter, 1990). Richmond and Hunter (1990) reported

P. lutea spawns during November and January (summer) on Australia's Great Barrier Reef. Obviously, our initial report is preliminary and will be refined with time.

The take home message is clear - not all corals spawn at night or do our observations of P. lutea's spawning behaviors correspond to any particular lunar phase. In fact, our observations suggest spawnings are random during periods of warmer water.

There is yet another possibility - some Porites lutea populations could use gonochoric brooding as a reproductive strategy, where sperm is released to the water column and fertilizes females' internally held eggs. This is rare in corals (estimated to be used by 7% of coral species) but has been reported in Porites rus colonies in Zanzibar (Bronstein and Loya, 2011). Hence, Porites species have been reported to use many reproductive modes - parthenogenesis, gonochoric broadcast spawning and gonochoric brooding (in addition to fragmentation).

Footnote

No observations, mostly due to time constraints of volunteers) of P. lutea spawning were made in 2010 (although they surely occurred). Our hopes are high for the 2011 spawning season, and we hope to have new information to report later this year.

References

1. Bronstein, O. and Y. Loya, 2011. Daytime spawning of Porites rus on the coral reefs of Chumbe island in Zanzibar, Western Indian Ocean (WIO). Coral Reefs, in press.
2. Fadallah, Y., 1983. Sexual reproduction, development and larval biology in Scleractinian corals: A review. Coral Reefs, 2: 129-150.
3. Fenner, D., 2005. Corals of Hawai'i. A Field Guide to the Hard, Black, and Soft Corals of Hawai'i and the Northwest Hawaiian Islands, Including Midway. Mutual Publishing, Honolulu. 144 pp.
4. Gulko, D., 1995. Hawaiian Coral Reef Ecology. Mutual Publishing, Honolulu. 245 pp.
5. Forsman, Z., D. Barshis, C. Hunter and R. Toonen, 2009. Shape-shifting corals: Molecular markers show morphology is evolutionarily plastic in Porites. BMC Evol. Biol., 9:45.
6. Kenyon, J., 1995. Latitudinal differences between Palau and Yap in coral reproductive synchrony. Pac. Sci., 49(2): 156-164.
7. Neves, E., 1998. Reproduction in reef corals. Results of the 1997 Edwin W. Pauley summer program in marine biology. University of Hawai'i, Hawai'i Institue of Marine Biology. Technical Report No. 42.
8. Richmond, R. and C. Hunter, 1990. Reproduction and recruitment of corals: Comparisons among the Caribbean, the tropical Pacific, and the Red Sea. Mar. Ecol. Prog. Ser., 60: 185-203.
9. Thongtham, N., Transplantation of Porites lutea to rehabilitate degraded coral reef at Maiton Island, Phuket, Thailand. Proc. 11^th Int. Coral Reef Symposium.
10. Veron, J.E.N., 2000. Corals of the World. Australian Institute of Marine Science.

Brian reveals specific details on how he successfully breeds these beautiful fish, giving you enough information to try it for yourself. As always, just send any questions to AmericanReef@me.com or sound off in the comments below.

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Todd Melman, of Reef Systems Coral Farms, gives viewers a brief overview of the pros and cons of having a coral farm from a business point of view. He also offers a special deal to American Reef viewers.

Send any comments to Americanreef@me.com or comment below this article in the comments section.

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After starting in this hobby almost 10 years ago, I became interested in learning about marine aquarium fish breeding one day after reading a post on the Reefs.org forums about success breeding species of clownfish. I wanted to do that! By nature I am a prolific reader, so I started searching for information both online and from book sources about breeding marine fish. I ended up purchasing a lot of great books on different marine organisms that I could breed or propagate: clownfish (Joyce Wilkerson) and (Frank Hoff), dottybacks, seahorses, peppermint shrimp, and coral. I was hooked.

A new book has recently become available for those interested in breeding marine fish: The Complete Illustrated Breeder's Guide to Marine Aquarium Fishes by Matthew L. Wittenrich. Below are the details of that book:

The Complete Illustrated Breeder’s Guide to Marine Aquarium Fishes: Mating, Spawning & Rearing Methods for Over 90 Species by Matthew L. Wittenrich

Publication Information	Produced and distributed by	Co-published by
ISBN 1-890087-71-8 Copyright 2007 by T.F.H. Publications, Inc.	T.F.H. Publications One T.F.H. Plaza Third and Union Avenues Neptune City, NJ 07753 www.tfh.com	Microcosm Ltd. P.O. Box 550 Charlotte, VT 05445 www.microcosm-books.com

Hardcover, 304 pages. List price $49.95.  Extensive charts, diagrams and photographs of various marine species being bred by marine hobbyists and professionals.

Table of Contents

Like the rest of you, I'm always interested in knowing beforehand what is covered in a potential book I'm interested in buying. The below Table of Contents will explain what all is covered in this volume:

Foreward: By Martin A. Moe, Jr.
Chapter 1: A Breeder's Journey
Chapter 2: Modes of Reproduction
Chapter 3: Broodstock Basics
Chapter 4: The Breeding Room
Chapter 5: Conditioning Broodstock
Chapter 6: Spawning
Chapter 7: Eggs & Incubation
Chapter 8: Larval Rearing
Chapter 9: Larval Nutrition
Chapter 10: Juvenile Grow Out
Chapter 11: Choosing the Right Species
Species Guides
Chapter 12: Pelagic Spawners
Chapter 13: Math & Motivation
Sources and Contacts
Photography & Illustration Credits
Selected Biography
Index
About the Author

If you want to use Amazon's "Look Inside" feature, click here to go to their page to review a couple pages inside the book..

Species Guides

For anyone interested in breeding, I'm sure you're interested in knowing what species are covered. Below is the list that's covered in this book:

Clownfishes – Subfamily Amphiprioninae

• Amphiprion ocellaris - Ocellaris Clownfish
• Amphiprion percula - Percula Clownfish
• Amphiprion melanopus - Red and Black Clownfish
• Amphiprion frenatus - Tomato Clownfish
• Amphiprion nigripes - Maldive Clownfish
• Premnas biaculeatus - Maroon Clownfish

Damselfishes – Family Pomacentridae

• Chrysiptera taupou - South Sea Devil Damsel
• Chrysiptera hemicyanea - Azure Damsel
• Chrysiptera paresema - Yellowtail Damsel

Dottybacks – Family Pseudochromidae

• Labracinus lineatus - Lined Dottyback
• Labracinus cyclophthalmus - Red Dottyback
• Pseudochromis steenei - Flamehead Dottyback
• Pseudochromis fridmani - Orchid Dottyback
• Pseudochromis aldabraensis - Neon Dottyback
• Pseudochromis olivaceus - Olive Dottyback
• Pseudochromis sankeyi - Sankey's or Striped Dottyback
• Manonichthys polynemus - Longfin Dottyback
• Pseudochromis wilsoni - Blue or Yellowfin Dottyback
• Pseudochromis springeri - Springer's Dottyback
• Manonichthys splendens - Splendid Dottyback
• Pseudochromis cyanotaenia - Yellowhead Dottyback
• Pseudochromis fuscus - Dusky or Yellow Dottyback
• Pictichromis paccagnellae - Royal Dottyback
• Pictichromis diadema - Diadem Dottyback
• Pictichromis porphyrea - Magenta Dottyback
• Ogilbyina veliftra - Sailfin Dottyback
• Cypho purpurascens - Flame Dottyback

Fairy Basslets – Family Grammatidae

• Gramma loreto – Royal Gramma
• Gramma melacara – Blackcap Basslet

Assessors & Comets – Family Plesiopidae

• Assessor flavissimus - Yellow Assessor
• Assessor macneilli - Blue Assessor
• Calloplesiops altivelis - Comet or Marine Betta

Jawfishes – Family Opistognathidae

• Opistognathus aurifrons – Yellowhead Jawfish

Cardinalfishes – Family Apogonidae

• Sphaeramia nematoptera - Pajama Cardinal
• Apogon cyanosoma - Yellowstriped Cardinal
• Apogon leptacanthus - Bluestreak or Threadfin Cardinal
• Cheilodipterus quinquelineatus - Fivelined Cardinal
• Pterapogon kauderni - Banggai Cardinal

Gobies – Family Gobiidae

• Gobiodon citrin us - Citron Goby
• Elacatinus oceanops - Neon Goby
• Elacatinus puncticulatus - Redhead Goby
• Elacatinus multifasciatus - Greenbanded Goby

Blennies – Family Blenniidae

• Meiacanthus grammistes - Striped Fang Blenny
• Meiacanthus nigrolineatus - Blackline Fang Blenny
• Petroscirtes breviceps - Mimic Blenny
• Pholidichthys leucotaenia - Convict Blenny

Seahorses – Family Syngnathidae

• Hippocampus zosterae - Pygmy or Dwarf Seahorse
• Hippocampus erectus - Lined Seahorse
• Hippocampus reidi - Brazilian Seahorse

Reef Basslets – Subfamily Liopropominae

• Liopropoma spp. - Reef Basslets

Angelfishes – Family Pomacanthidae

• Centropyge spp. - Dwarf Angelfishes
• Pomacanthus spp. - Large Angelfishes

The Details

A detailed analysis of the book follows. Skip to the end if you'd rather see my recommendation on the book.

Foreword

Martin Moe, Jr. starts out the book where he discusses the past, present, and future of marine breeding.

Chapter 1: Breeder's Journey

Chapter 1 begins with Matthew's history of how he went from breeding freshwater fish as a child to breeding marine aquarium species to obtaining his degree in marine biology. He also talks about why captive breeding is important to our hobby and reviews efforts made by Martin Moe, Jr., Frank Hoff, Tom Frakes and others in this field. He makes it clear that this book is intended as a guide and that you as the breeder will face challenges in your breeding efforts but that you will also gain a lot of satisfaction from pursuing it.

Chapter 2: Reproduction

Matthew discusses the different modes of reproduction that marine fish utilize when spawning, how the larvae differ, and how they settle after metamorphosis. General information is given on how spawning systems will need to be setup to accommodate different spawning behaviors. He also talks about the different sex of fish and how some are a predetermined sex and others exhibit hermaphroditism. Some anatomy basics are also given.

Chapter 3: Broodstock Basics

The topic of this chapter centers on picking healthy starter stock and the conditions necessary for inducing spawning. Pair formation is discussed and how a breeder can induce pair formation by using divided, bi-directional, and pairs vs. trio methods depending on the species of fish.

Chapter 4: The Breeding Room

A lot of information is disseminated in this chapter (it's one of the top three longest in the book). Tank types and sizes, setup, controlling the nitrogen cycle, filtration utilizing wet/dry filters, skimmers, etc are discussed, in addition to draining methods, quarantine, photoperiod, temperature, and oxygen requirements.

Chapter 5: Conditioning Broodstock

Matthew states that food quality is very important for proper conditioning and that we as breeders need to replicate to the best of our abilities the fish's normal diets in order to maximize our chances with them breeding in our systems. Protein, carbohydrates, fats, and other nutrients are reviewed. A good recipe for frozen food is given. Live foods are also discussed.

Chapter 6: Spawning

Matthew goes into more detail on spawning methods, acts, and cycles that fish utilize during breeding. For problematic fish, ideas on how to induce spawning are also given to the reader.

Chapter 7: Eggs and Incubation

Here, hatching methods are reviewed and natural vs. assisted methods are discussed and what the breeder needs to know about each method. Troubleshooting guidelines are given on how to handle certain situations and how lighting, parasites, water quality, etc. affect fertilized eggs.

Chapter 8: Larval Rearing

Housing utilized for newly hatched larvae is important and the tank's size, shape, and setup are all reviewed. He makes note that dedicated larval rearing systems need to be utilized and gives rearing options for different larvae.

Chapter 9: Larval Nutrition

This is the second longest chapter in the book, which in this author's opinion shows how important it is for the breeder to learn this subject. Feeding performance of the larvae is discussed and food sources are given. Culturing of microalgae is discussed in addition to using instant algaes from one of our sponsors, Reed Mariculture. Rotifers are also discussed along with rotifer contamination of microalgae cultures. Hatching brine shrimp is also reviewed and harvesting and feeding of live foods is talked about.

Chapter 10: Juvenile Grow Out

Metamorphosis and rearing young fish to adulthood is the focus of this chapter. A number of great illustrations are given of various species of fish from the first day past hatching all the way through adulthood. Grow out aquariums are examined as well as when juvenile fish should be moved from the larval rearing tanks to their grow out tank. A troubleshooting guide is given to aid the breeder in diagnosing inferior eggs, weak larvae, fungal attacks, hatching problems, etc. Culling, while the breeder hates to do it, must be done and what the breeder should be looking for when he or she is culling fish.

Chapter 11: Species Guides

This is the longest chapter in the book. Almost 100 pages are dedicated to the species listed earlier in this article with information given on the fish's family, genus, and species, as well as aquarium size, establishing broodstock pairs, foods, and spawning. The locale from where each fish species is typically collected from is given along with their adult dimensions, sex allocation, their habitat and range, sexual dimorphism, spawning habits, diet, larval rearing, etc. The chapter contains numerous photos to illustrate species. The reader is encouraged to start out with a simple species first to get their feet wet breeding before advancing along to the more advanced species.

Chapter 12: Pelagic Spawners

These are the ultimate challenge for the home breeder as they need large water volumes and/or tall tanks in order to spawn effectively. Fish like wrasses, reef basslets, anthias, etc are all pelagic spawners and will be a lot harder for the home breeder to accommodate. Pond culture is one way to get around this problem and is currently the way that the red sea yellowbar angelfish (Pomacanthus maculosus) is reared. New techniques will need to be designed as well as new food sources in order for home breeders to make it work.

Chapter 13: Math and Motivation

The question asked in this chapter is: "how will you gauge your success as a breeder?" Matthew takes the reader through a real-world math exercise on how realistically you'll be doing business. He discusses selling your raised fish to local fish stores vs. wholesalers and how to optimize your business. Breeding for conservation is important as is preserving biodiversity.

Sources and Contact

At the end of the book is a long list of sources and contacts for just about anything the home breeder will need. Sources for food, equipment, and broodstock are given. A detailed bibliography is also cited where the reader can go to obtain more information on a specific topic that they'd like clarification on.

Is the book worth purchasing?

This is a resounding "Yes" if you are either a current breeder or a beginner wanting to learn more about breeding marine fish. In this author's opinion, The Complete Illustrated Breeder's Guide to Marine Aquarium Fishes by Matthew L. Wittenrich covers the subject matter well giving the reader a thorough look at how to begin breeding marine fish. Aquarium selection, broodstock, nutrition, larval rearing, grow out, and selling are all covered in good detail to get the breeder started out in the right direction. The detailed bibliography at the end of the book is also something the reader should refer to in order to find more information about the fish(es) that he/she wants to get into breeding. This is a must-buy for anyone intererested in marine aquaculture.

The May 2010 issue of Advanced Aquarist segues nicely with my editorial of last month where I appealed to aquarists, both professional and amateur, to stock with aqua cultured, rather than wild caught animals, at least as much as possible. Shane Graber, our webmaster, reviews in this issue "The Complete Illustrated Breeder's Guide to Marine Aquarium Fishes: Mating, Spawning & Rearing Methods for Over 90 Species" by Matthew L. Wittenrich. Marine aqua cultured fish are becoming more and more numerous, and thereby offering aquarists greater choices. Furthermore, in my experience, aqua cultured fish whether marine or freshwater flourish far better in our glass cages than do wild caught fish.

Almost 50-years ago I kept discus fish (Symphysodon discus) with only marginal success. In those days the only discus available were wild caught. What I remember was that getting them to feed was a problem - they would only eat live tubifex worms - and often died from what was called hole in the head disease. Today, 50-years later, I have added several aqua cultured discus fish to my community planted tank, where they eat everything - including flake food - and have shown no sign of hole in the head disease.

As aquarists we should try to limit our carbon foot print as much as possible, especially since maintaining a reef tank or freshwater planted tank requires a significant amount of electrical power. Generating enough light is probably the most energy demanding. In this issue we have two articles, one by Dana Riddle and the other by Sanjay Joshi, evaluating the LED fixtures that are becoming available to aquarists. The significance of LED lighting is that their power consumption for a given amount of illumination is much lower than that of other lighting types.

In 2005 I purchased my first Toyota Prius. When compared to other cars of that size it was about 20% more expensive. However, in the five years that I drove it about 20,000 miles yearly it averaged about 50-miles per gallon. The result, I saved money and helped the environment. I just traded it in for the 2010 model. I mention this because the same may soon be true for LED lighting for aquariums that require intense lighting. As I said before' the struggle is always between short term commercial interests and long term quality of life interests, and in this case the life of our captive animals.

SECORE (Sexual Coral Reproduction), the international group dedicated to reef restoration and conservation research, has had amazing success recently in both rearing captive Acropora palmata, and out-planting these endangered corals on dead colonies, from larvae fertilized in the field. Join a discussion of this subject between Gary Linder of American Reef, and SECORE member Bob Snowden of The Pittsburgh Zoo and PPG Aquarium. Part 2 of 2. Send any comments to Americanreef@me.com or comment below this article in the comments section.

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Editors Note: Richard Ross originally wrote about his work with husbandry and breeding of Sepia bandensis back in our September 2005 issue: http://www.advancedaquarist.com/2005/9/aafeature.

Anchored to an algae-covered rock in a 120-gallon tank at the California Academy of Sciences' Steinhart Aquarium, a cluster of inky-colored cuttlefish eggs is beginning to swell—evidence of success for the Academy's new captive breeding program for dwarf cuttlefish, Sepia bandensis. The program, pioneered by Academy biologist Richard Ross, is the first of its kind in a U.S. aquarium, and offers the Academy and other institutions the opportunity to study and display a species that is both captivating and—at 2-4 inches in length—less resource-intensive to keep than its larger relatives. "By establishing a stable breeding population," Ross explains, "our hope is to make it easier for aquariums to showcase cuttlefish and their remarkable characteristics without impacting wild populations."

While called "cuttlefish," these animals are actually not fish at all—they are members of the class Cephalopoda, which also includes octopus, squid, and the chambered nautilus. Perhaps best known for their highly developed brains, nervous systems, and eyes, cephalopods are a fascinating group of animals to both researchers and aquarium visitors. For scientists, cephalopods' advanced capabilities pose a host of unanswered questions about the nature of intelligence in invertebrates and vertebrates. For everyday observers, the dwarf cuttlefish is a captivating ambassador to its Cephalopoda class, and its native Indo-Pacific region. Able to rapidly change its skin color, Sepia bandensis frequently flashes moving patterns across its skin, and can quickly blend into its surroundings—phenomena that can be seen regularly in the Steinhart Aquarium display. Beneath that ever-changing skin, the dwarf cuttlefish's physiology is equally remarkable, with three hearts, and an esophagus that passes through its brain.

Behind the scenes at the Academy, hundreds of tiny hatchlings—exact replicas of their adult counterparts—are being hand-fed at least twice a day. In developing the breeding program, one of the most significant challenges Ross faced was identifying a successful feeding strategy for young hatchlings in the absence of existing literature. The key, he has discovered, is that young cuttlefish require live meals beginning with mysis shrimp, and increasing in size with age. Hunting with a pair of feeding tentacles, dwarf cuttlefish can devour prey the length of their own bodies.

As the eggs on display at the Academy continue to expand, they transition from an inky purple to translucent, at which point the babies can be seen swimming inside their egg casings. To date, more than 350 dwarf cuttlefish have hatched at the Academy, most of which have been sent to other aquariums and research institutions. Since North American waters do not house any native cuttlefish, only a handful of species are currently seen in zoos and aquariums in the United States. Now that these small animals are available from a sustainable captive source, Academy biologists hope that other zoos and aquariums will take advantage of the opportunity to share these intriguing animals with their visitors as well. This new captive breeding program joins several others that the Academy participates in, including those for African penguins, and golden mantella frogs, all of which are aimed at protecting populations in the wild.

About the Steinhart Aquarium

The California Academy of Sciences' Steinhart Aquarium is one of the most biodiverse and interactive aquariums in the world. Home to an estimated 38,000 animals representing more than 900 separate species, it offers visitors an unprecedented view of underwater life and provides insight into the critical role that aquatic environments play in life on Earth. The original Steinhart Aquarium opened in Golden Gate Park in 1923, and today it houses a stunning new suite of exhibits, including the world's deepest living reef tank, a four-level rainforest display, and a unique, ever-changing Water Planet exhibit.

About the California Academy of Sciences

The California Academy of Sciences is a world-class scientific and cultural institution based in San Francisco, home to Steinhart Aquarium, Morrison Planetarium, and Kimball Natural History Museum, along with research and education programs. In 2008, the Academy opened a new LEED Platinum-rated facility, and remains the only institution in the world to combine all of those elements under one roof. Founded in 1853, the Academy is driven by a mission to explore, explain and protect the natural world. Visit www.calacademy.org for more information.

Contact: Stephanie Stone
sstone@calacademy.org
415-379-5121
California Academy of Sciences

I recently started a new saltwater system and very quickly discovered a need for a cleanup crew. Fortunately, I've been associated with the Reef Stewardship Foundation (RSF, formerly also known as "The Desirable Invertebrate Breeding Society" or "Project DIBS"), which has as some of its goals:

1. To identify marine animals that can be bred in our aquaria and
2. To encourage aquarists to keep and distribute these animals to other aquarists as a way to help reduce the impact of the aquarium hobby on wild ecosystems.

Through the Foundation, I was able to locate an aquarist who sent me small populations of several species of appropriate animals. These creatures make good cleanup crew members, are known to breed in aquaria, and whose offspring will grow to adulthood in reef tanks. The wonderful thing about these animals is that their populations can expand over time to meet the cleanup needs of any system, also making them very economical choices in addition to the important conservation considerations.

Within a few days of receiving my cleanup crew shipment I began seeing small lenticular egg capsules (about 2 millimeters across the circle, each containing about six eggs) appear on the glass. I took a photo of one of the capsules and asked if anyone at RSF knew the species that made them. To my surprise, no one available at the time could identify the species that deposited the egg capsules. For some of the RSF invertebrate species that we know can reproduce in captivity, we still know very little about their reproductive behavior; we don't know how or why they can reproduce in captivity. Knowledge of how the larvae of these species develop can make it easier to tailor culture tanks to the species' needs, allowing as many of the larvae as possible to reach adulthood. With that in mind, I began an effort to document the development of these eggs in the effort to aid future identification of these egg capsules and to find out why these animals are successful at reproducing in hobbyists' aquaria. It's my hope that the knowledge gained can help to maximize the production in captivity of these helpful creatures.

Although the developmental sequence is shown, the reader should note that the photos in this article are not a true series taken with one egg capsule. My techniques for photographing these eggs improved during the course of this process, so I went back to re-photograph early stages of development later with other egg capsules.

Development Basics

Snail development, as with most animals, begins with parental gamete combination into a zygote-a single large cell that is also called the "fertilized egg." In this species the mother snail deposits 5-8 of these zygotes-along with additional nutrients in the form of yolk for each individual zygote and also a nutrient-filled fluid that surrounds them-in a membrane capsule attached to a hard surface, in this case the aquarium glass. The eggs are released from the oviduct under the right edge of the snail's shell aperture and transferred to the bottom of the foot. The membrane capsule is secreted through an opening in the bottom of the mother snail's foot. This anatomy is perfect for leaving eggs behind on hard surfaces that she visits without exposing the snail to any increased risk of predation. She then secretes a seal that closes the capsule and isolates the developing embryos from their surroundings until the young are ready to start feeding from the larger environment.

It's important that the female eat well in the time before depositing eggs: Until the larva leaves the protective membrane and begins to hunt and feed from other sources, the nutrition contained in the yolk and the surrounding nutrient fluid is all the energy reserves that the larva will be able to draw upon to fund the incredible changes that lie ahead. All of the energy for every egg capsule the mother leaves behind must come from the mother's energy reserves, and this amounts to a significant amount of parental "care." Fortunately, the snails provided by RSF eat nuisance algae and providing enough algae for them to breed is not only not a problem in most aquarists' tanks, but is a positive benefit from these species' standpoints.

Developmental changes for the zygotes begin with a simple act. The cell divides itself into two cells and, with that, the zygotes become embryos. The process continues at roughly a cell division every hour or two at tropical temperatures depending on the specifics of each species, with two cells dividing into four, four into eight, and so on. When an embryo reaches roughly 120 cells (around seven divisions of all the cells), the cells organize themselves into a blastula-a round, hollow aggregation of cells that marks the first time that it really makes sense to talk about an inside and outside of the embryo.

I have no way to tell if it is true for this species of snails, but for many invertebrate larvae the very next cell division-number eight-results in creatures with rudimentary but functional locomotory systems, sensory systems, mouths, and digestive systems. That is, eight cell divisions-8-16 hours at tropical temperatures-and only one cell division after the very first time the creatures even have insides results in creatures that can search for, move to, eat, and digest food. Incredible! With the capability of feeding itself, the developing creature has become a "larva."

After this, the larva's major systems continue to develop and become more complicated for the next couple of weeks. A transparent shell develops. The larva's small foot begins to grow. Finally, a cilia-covered structure called the "velum" develops. It's this velum that gives snail larvae their name: "veligers." The velum looks like nothing more than it looks like giant Mickey Mouse ears extending out of the larva's shell. These "ears" are (comparatively) giant lobes with long cilia around the margins. The snail's mouth lies at the intersection at the base of the two lobes. With their beating actions, the cilia on the velum allow the larva to swim relatively quickly. In addition, the cilia also propel small food particles toward the snail's mouth. If this were a species with a planktonic life stage, the development of the velum would mark the point where the larvae could begin their life in the plankton, moving to and eating the unicellular algae that proliferates there.

But, this stage is where these specific RSF snails differ from the majority of marine invertebrate larvae and is what makes them easy to breed in captivity. These snails remain inside the egg capsule membrane for several days after the development of the velum, continuing to feed on the nutrient-filled fluid their mother deposited in the capsule for them.

I was surprised to find a sudden large developmental change one morning (only twenty-eight days after introducing the parent stock to the aquarium). Overnight, the young snails had pulled the two lobes of the velum together, forming them into a hollow tube. With this development of the feeding tube, the larvae finally really began to look like their adult relatives. At this point, the creatures are no longer veliger larvae and have made the transition to juvenile snails.

Within a couple of days after this species' transformation into juveniles, the plug over the escape hole disintegrates and the new juvenile snails escape to try their luck in the outside world.

Timeline

To give you an idea of how quickly this process took place, here is a timeline of the major events that occurred:

• March 4 The shipment of animals was received from fellow RSF aquarist.
• March 22 I noticed egg capsules all over the glass. Some of the egg capsules were already weeks into development.
• March 27 The most advanced larvae already had large velums and shells that were on their second whorl.
• April 1 The most advanced larvae's velums changed to feeding tubes.
• April 3 The most advanced capsules opened, releasing juvenile snails to the open tank.

Thirty days from parental introduction to the aquarium to the release of free-living juvenile snails!

Who's the Lucky Mother?

By comparing the first two whorls of the juveniles' shells with the remnants (eventually, snails' shells begin to wear with the rigors of life in the world) of the first two whorls of the various adult snails in my system, I theorized that the eggs likely came from a small species of Collumbellid snail, a voracious eater of hair algae. It looks like my system will soon be crawling with these snails. Once the algae in my system is under control, I can start removing snails as necessary and trading them with other hobbyists and fish stores, thus allowing me to export nutrients from my system that are bound up into the snails' bodies. I much prefer to export nutrients by simply removing snails than by scrubbing hair algae with a toothbrush. Plus, these snails are a more valuable commodity to me than the hair algae that can only be turned into compost for my garden.

A Call to Captive Breeding

Honestly, I can hardly see a reason not to participate in the captive breeding of marine invertebrates. We hobbyists need cleanup crews. Constantly removing cleanup crew members from the oceans that don't survive well in aquariums is both expensive and-finally-not nearly as necessary as it used to be because species have been found that are fairly easy to raise in captivity. I'm proud to be a part of the Reef Stewardship Foundation's efforts in these areas. Hopefully, as the knowledge base grows, more easily raised species will be found and protocols will be added for harder species so that the foundation's list of captive-bred species available to hobbyists will continue to grow.

A Postscript

Shortly before finishing this article, I managed to catch sight of a mother Collumbelid in the process of depositing one of these egg capsules (and that's how I knew that the eggs in photo 1 were only a few minutes old). So, the sighting confirms the theory about the identity of the snail species and gives me another photo of these lovely creatures to show you.

Acknowledgments

I would like to thank my wonderful family for their continuing encouragement and enthusiasm for my aquarium hobby, and for their love and support. I would also like to thank Ron Shimek, who encouraged me to write this article and gave generously of his time and knowledge to help me edit the manuscript and ensure that I explained the science behind the snails' development correctly.

References

1. If you would like to learn more about the Reef Stewardship Foundation or would like to join its efforts to breed marine invertebrates in your tanks, please point your Web browser to the RSF website: http://www.reefstewardshipfoundation.org/
2. Ruppert, Edward R., Richard S. Fox, and Robert D. Barnes. 2004. Invertebrate Zoology: A Functional Evolutionary Approach. 7th ed. (Belmont, CA: Brooks/Cole-Thompson Learning).
3. Shimek, Ronald L. 2007. "Spawning, Embryogenesis." Lecture essay 2 from Invertebrate Embryology and Larval Biology for Reef Aquarists, an online course presented to Project DIBS (now the Reef Stewardship Foundation).
4. Shimek, Ronald L. 2007. "Larvae." Lecture essay 3 from Invertebrate Embryology and Larval Biology for Reef Aquarists, an online course presented to Project DIBS (now the Reef Stewardship Foundation).

All photos in this article copyright © 2009 by Andrew Berry.

In Part Two, American Reef concludes their discussion of coral reproduction and captive propagation. They also talk about the conservation activities of SECORE (SExual COral REproduction). This international organization hopes to tackle reef conservation issues by increasing our knowledge of coral reproduction and husbandry, through the cooperation of zoos, public aquariums, and marine scientists. Send all comments to Americanreef@me.com

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