What is the “origin story” for a marine legend? Marine biologist Martin Moe earned his master’s degree in marine biology at the University of South Florida (USF), where he later did postgraduate work toward a doctorate. In between he worked as a state biologist from 1961 to 1969 on several projects. Perhaps the most important was developing and refining a protocol for culturing pompano (Trachinotus spp.), an important marine fish. Moe’s work on pompano for the state and later a private company formed the foundation for his work with marine clownfish.
Solving A Pompano Feeding Dilemma
Getting clownfish or pompano to spawn wasn’t a problem, but growing them from larvae to juveniles required motile, live food that was smaller than brine shrimp nauplii, which were too large for them to eat and not particularly nutritious. Marine biologists at that time were using sifted, wild zooplankton to feed larval marine fishes.
During Moe’s efforts with pompano, he learned that Reuben Lasker of the Scripps Institution of Oceanography was conducting plankton dynamics studies using microalgae to feed cultured rotifers (Brachionus plicatilis) that were then fed to his laboratory zooplankton. Lasker obtained these rotifers from Japanese colleagues using them to raise marine fishes.
Moe discussed the pompano project with him, and Lasker shipped him rotifer starter cultures to feed the larval pompano. Lasker also sent suggestions on algae culture. Moe successfully spawned and hatched pompano eggs and grew their larvae on rotifers all through the larval stage and metamorphosis to juveniles.
His pompano progress caught the eye of a private aquaculture company that offered him a position as director of research aimed at farming pompano. It was an attractive offer, and Moe left his state job for the research fish farm project, delivered the refined protocol for producing pompano (using rotifers), and then left that company to return to USF and continue his graduate studies.
Moe had built a lab in his garage where, on his own time, he tried the new pompano techniques to see if they would work on clownfish. He had long been a skilled aquarist as well as a biologist who knew the tools of maintaining water quality like ozone, UV, foam fractionation, trickle filters, canister filters, ion-exchange resins, and the value of water changes. He knew lighting, recirculation, and the role of diet in getting brood stock to produce healthy eggs that would hatch and fry that would survive.
Copepods are ideal in size and nutritive value, but were not being laboratory-cultured. If you wanted them, you had to collect wild zooplankton with nets, pick out the predators and sift out the copepods. He’d been collecting plankton and removing predators like arrow worms and overly large zooplankton for larval pompano (and at home for larval clownfish). He collected plankton every day, because it does not last in a bucket and loses nutritional value before that. Basically, growing larval marine fish is a 24/7 job.
His success with pompano and thereafter with clownfish, beginning with copepods and soaring with rotifers, fueled the marine fish breeding success story. He started with pompano, growing them the standard way with wild zooplankton, discovered the use and value of rotifers, and applied this to breeding first pompano and later tropical marine fishes.
Success With Marine Fish
In 1973, after successfully producing clownfish in large numbers, he established Aqualife Research Corporation (ARC), acquired the tools he needed to grow both rotifers and their food (algae) and began to rear the anemonefish, Amphiprion ocellaris (then known as “percula”) and other marine species. Several aquarists had spawned percula and tomato clownfish, and even raised a small number from the larval to the juvenile stage. Moe saw no reason clownfish could not be grown in quantities like other commercially important fish. And tank-raised fish carried no wild fish diseases.
Moe’s first successful “percula” clownfish spawnings began in 1972. In 1973 he showed his tank-raised clownfish at an aquarium show, and Robert P. L. Straughan wrote about this breakthrough achievement in The Aquarium magazine.
The hobby was suddenly changed.
In 1973, Moe moved ARC operations into an old icehouse in St. Petersburg, Fla., that would become a commercial production site for marine fish. He hired two employees, and the hatchery was soon up and running. In 1975, ARC moved to Marathon in the Florida Keys. In 1983 he built a larger hatchery on Walker’s Cay in the Bahamas. Moe left ARC in 1988 and wrote books. In the 1990s he did aquaculture research using the orchid dottyback. He moved back to Florida in 1999, where he has been ever since.
Moe built a new hatchery in 2006 and reared yellowhead jawfish (Opistognathus aurifrons) and blackcap gramma (Gramma melacara). Currently, his research is focused on sea urchins.
Many earlier successes occurred at Moe’s home labs or at the ARC hatchery in St. Petersburg. Early on, Moe saw better egg survival after he enhanced the diet of the breeders with fish roe and shrimp. He got even better results after putting back the shrimp shells he previously discarded when preparing a fish-shrimp food mix for the adult fish. He couldn’t maintain as many algal or rotifer cultures in his garage lab as he needed, but the ARC icehouse in St. Petersburg was large enough to support many cultures of marine algae generously supplied by university and aquaculture sources. He tried them all.
Which microalgae would grow rotifers fastest? Which had the highest concentrations of highly unsaturated fatty acids (HUFA)? Menhaden oil was a cheap industrial product rich in HUFAs. Could fish oil-based supplements enrich the cultured rotifers or nauplii of brine shrimp when the fish outgrew the rotifers? These questions needed room (and help) to investigate.
Fish oil-enriched rotifers increased clownfish production and survival, which jumped from a dozen to hundreds of larvae surviving metamorphosis to juveniles. From two pairs of breeders he raised (and sold) thousands of tank-raised percula clowns and expanded into other clownfish species, neon gobies and, later, more than a dozen marine aquarium fish species.
Each species presented unique problems. What worked with one species didn’t work with all. Dottybacks were so challenging that Moe recorded his efforts in a book about these gorgeous cave spawners that seemed to prefer killing to spawning. He worked it out. While everyone was still trying to breed them, Moe was raising 351 orchid dottybacks (Pseudochromis fridmani) from a single spawn in a 20-gallon tank.
Not every laboratory breakthrough was a commercial success. He captured adult gray and French angelfish by chasing them into the rocks, placing large cast nets over the escape routes, and chasing them back out into the nets. Wrapped in cast netting, he brought these large fish up to the boat, placed them in containers for the ride back to the lab, stripped them (forced out the roe and milt by gentle squeezing), mixed the gametes and washed them, and then released the parents back into the wild.
He incubated the fertilized eggs, hatched and nurtured the young in small numbers, but they refused to eat rotifers, which forced him to fall back on collecting wild plankton again. On top of that, the young died if he didn’t keep the tanks brimming with streptomycin. Growing angelfish was too labor-intensive. He spawned pygmy flame angelfish in 1996 but found the eggs needed special water conditions to survive to hatching, and he did not rear them to metamorphosis. He spent eight years trying to find solutions to angelfish problems and then moved on.
He hit other bumps like “toxic tank syndrome” that he described in 1973. He illuminated the importance of chlorine disinfection of spawning and rearing tools. Today, marine aquaculture facilities include disinfection and antibiotic prophylaxis as standard operating procedures. All these findings come at a high price.
Spreading The Word
Moe still cooperates on projects with scientists everywhere. Today he’s back to a smaller operation at home on Plantation Key, Fla., and relies on Dr. David Vaughan of the Mote Marine Laboratory’s Tropical Research Laboratory in Summerland Key, Fla., to replenish his marine algal cultures every couple of weeks. He’s been interviewed by most aquarium magazines and spoken to numerous aquarium societies. He often speaks at the annual MACNA conference.
Moe’s books include Marine Aquarium Handbook: Beginner to Breeder, The Marine Aquarium Reference: Systems and Invertebrates, Lobsters: Florida, Bahamas, and the Caribbean, and Breeding the Orchid Dottyback: An Aquarist’s Journal. Moe has also contributed to other books, including Natural Reef Aquariums, The Complete Illustrated Breeders’ Guide to Marine Aquarium Fishes and The Marine Fish Health and Feeding Handbook.
Save The Sea Urchins, Save The Reef?
Coral reefs have suffered from wastewater, industrial discharges, septic tank seepage, atmospheric heating, sedimentation from channelization, onshore construction and deliberate (garbage) or accidental (oil spill) dumping, and people not paying attention while driving a boat.
Now Atlantic reefs are threatened. In 1983 a disease of long-spined sea urchins (Diadema antillarum) appeared on coral reefs offshore of the Panama Canal. Normally urchins crop macroalgae and preserve settling habitat for the annual crop of new corals. The cause of this “plague” of urchins is unknown, but it might be infection by anaerobic spore-forming Gram-positive bacteria. A similar disease was reported by European researchers in related animals (echinoderms).
Moe, in a SeaScope newsletter (vol. 20, issue 4, 2003) documented the spread of the plague and calculated it had been introduced and spread throughout tropical Atlantic reefs in just 13 months. The European investigators reported a similar outbreak they called Bald Urchin Disease, because it caused the urchins to drop their spines and die in days. In American waters the plague affects primarily long-spined sea urchins, the dominant urchin on our coral reefs.
The consequences were immediate. The urchins, according to Moe, are keystone species that control the fundamental ecology of the reef. Sea urchin consumption of macroalgae keeps it at bay. Without them, normal crustal algae on which new corals settle no longer have a foothold on the reef. The annual recruitment of new corals stops and coral reefs transform into forests of macroalgae covering dead remnants of the reef.
Although Clostridium bacteria are suspected as the cause of the Diadema plague, it was never scientifically confirmed, and the cause is always expressed as an unknown pathogen.
Propagating Sea Urchins
Suppose disease-resistant urchins could be produced in aquaculture from the survivors of the plague. How many urchins would it take? Could they be produced? What would be the minimally effective density for sea urchins to take off on their own?
Moe and Ken Nedimyer, an aquarist and president of the Coral Restoration Foundation, conducted a study beginning in 2001 on two experimental and two control Florida reefs to see if they could collect and transfer plague survivors at sufficient density to protect a reef. First they collected juvenile urchins from an offshore rubble zone. These urchins had a short life expectancy in these habitats. Moe and Nedimyer placed the juvenile urchins on two experimental reefs in numbers equal to the earlier population density recorded from a benthic analysis. They didn’t put any urchins on two control reefs.
When they counted the surviving urchins and estimated reef conditions two years later, the results showed that the two experimental reefs with transplanted supplemental urchins were recovering and the control reefs were not.
Some urchins survive the plague, and Moe began developing methods to propagate them in numbers in 2001. For this stage, he works with Vaughan, who provides marine microalgae needed by urchin larvae. Moe’s algae capacity is limited while the Mote laboratory has a far greater capacity.
Culturing sea urchins was not a slam dunk. Baby urchins didn’t develop, they dropped their larval spines, they didn’t metamorphose into juveniles and seemed to die at about 3 weeks of age. Not all algae are good urchin food. They settled on Rhodomonas and Isochrysis.
Besides the breeding issue, there were questions about brood stock. Should they take urchins from an uninfected reef or from the survivors of a decimated reef?
Even spawning the urchins posed a problem. In freshman college biology lab, the usual way to get sea urchins of the genus Lytechinus to emit sperm and eggs is by needle stimulation or exposure to potassium chloride. During Moe’s work, he found that simple heat shock would suffice for the Diadema, with no chemical contamination.
So, he had no problem getting larvae, but waiting for the larval stage to run its course until metamorphosis to the juvenile (a miniature adult) revealed two problems: holding the larvae in protracted suspension and feeding the earliest-stage larvae before settlement and metamorphosis.
Suspension was needed because otherwise the larvae would sink and die. But aeration was rough and broke them apart. Moe finally kept the larvae suspended by pulsed aeration from a wand set at one end of the culture vessel for periods of four seconds on and 30 to 60 seconds off. This kept the water in circulation without damaging the larvae. And these larvae didn’t metamorphose until 35 to 50 days of age.
Why so long? It’s not that long if you’re a sea urchin! The blastula appears on Day 2 and the larvae start feeding soon after. By Day 60, the metamorphosed juvenile is feeding on algal growth growing on the acrylic vessel. By the 100th day, they are miniature long-spined sea urchins.
The goal is to produce enough urchins to supplement surviving urchins on problem reefs with (hopefully) disease-resistant, laboratory-reared urchins. Moe collected surviving urchins from decimated reefs, assuming these were somewhat resistant to the pathogens. Moe said he has spawned and reared the F1 generation and used these to spawn and rear the F2 generation. He has conducted about 28 rearing runs, producing juveniles in about a dozen runs, but he’s produced long-lived juveniles in only two runs.
Restoration will require a minimum population density of long-spined sea urchins sufficient to induce sustainable annual spawning. The urchins must be near enough to each other to induce egg or sperm release into the water. Moe and coworkers want to add just the right number of supplemental urchins to get them all to spawn. That requires a lot of production and husbanding the supply to repopulate the most reefs with the least effort. It will take years.
Looking To The Future
Asked what tank-bred marines were available to the hobby now, Moe replied, “We’re producing 35 varieties of clownfish here, and at least 70 species of marine fish are generally available.”
And there is an unending need for tank-bred marine species for the hobby, as well as restoration. The marine hobby is constrained by restrictions on collection and export for profit, and getting coral fish is difficult and complicated by the potential to bring in parasites we’re trying to avoid. Some parasites multiply rapidly and can jump from fish to fish. Tank-bred and raised fish don’t carry that risk.
“Aquaculture can provide a sustainable supply of disease-free fishes,” Moe said. “Well-equipped facilities scale up for multiple projects. One hatchery needn’t be restricted to one project at a time. Public and private aquariums can do more than we’re doing. Aquariums could serve as species banks for restoration or enhancement projects.”
Having this option in our toolbox is a game-changer for managing repairs and reparations for unforeseen reef damages.
Moe wants new and better products for home fish breeders. When algae paste was introduced, it became a huge labor-saver. New tools and products will bring more breeders into the hobby. And that’s good for everyone.
What about new fish? “I’m glad you asked,” Moe said. “I’m experimenting with ‘small-egged’ fish with eggs 500 to 900 microns — under 1 millimeter — in diameter, that require a first food smaller than rotifers. That would add dozens of additional marine fishes to commercial aquaculture.”
He added, “My research now and in the foreseeable future will be with Diadema and, although I would like to work with fish once more, I’m not sure when that will happen.”
Read Martin Moe’s article about keeping a successful marine aquarium at FishChannel.com/MarineAquariumTips