Are Aquariums Getting Too Lifelike?

Henry Fountain, The New York Times 23 Mar 10;

On the reefs in the Florida Keys, plenty of snorkelers and scuba divers take in the sights, and others fish with spear guns for sport. But a small third group collects blue-legged hermit crabs, peppermint shrimp and other invertebrates, not for food or fun, but for the aquarium trade.

There are an estimated 700,000 saltwater home aquariums in the United States, and tropical fish with a bit of rock and a plastic Diver Dan are no longer enough to satisfy the keepers of many of these miniature oceans. The fish are still there, but as technology and technique have improved, the aquariums are now often small-scale reef ecosystems, with living coral and “live” rock brimming with anemones, shrimp, sea urchins, crabs and snails.

The result has been a growing market for these and other reef invertebrates, many of which are supplied by about 165 licensed collectors in Florida.

Those involved in the Florida fishery, which is concentrated in the Keys, say that it is sustainable and more closely managed than many others, with no new licenses permitted and daily limits on many species.

But scientists argue that the collecting poses a threat to the very ecosystems aquarium hobbyists aim to replicate. Aside from the long-recognized ecological impact of the trade in live coral itself, these researchers say the demand for invertebrates — creatures that often serve the same cleaning and pest-control roles in a tank that they do in nature — is such that the fishery may be unsustainable.

“We may be increasing the catch up to a point where you push something over the edge,” said Andrew Rhyne, a marine biologist with Roger Williams University and the New England Aquarium who has studied the Florida invertebrate fishery. “The question is, where is that edge?”

If a species is overharvested to the point where its numbers decline dramatically, Dr. Rhyne and others say, there can be a cascading effect in the ecosystem. Without invertebrate grazers and herbivores, for example, a reef may be overrun with algae.

Jessica McCawley, a biologist with the Florida Fish and Wildlife Conservation Commission, disagrees that the fishery is threatened. She helped update the regulations last year, and said: “These collectors are a special type of fisherman. They’re very concerned about the environment and the sustainability of the fishery. And they came to us and said, ‘Can you put some regulations on us?’ ”

Collectors also say that scientists don’t have the experience they do in seeing these invertebrates go through regular cycles of bust and boom.

Pete Kehoe, who has been collecting marine life near Key West for 35 years, recalled that after Hurricane Ike in 2008, he found one reef that had been scoured clean of blue-legged hermit crabs, which are valued in reef tanks because they eat detritus, helping to keep the coral clean. “You couldn’t find a shell on that reef,” he said.

But two years later, he said, the crabs have recovered, and then some. “The other day we were on that reef and someone said, ‘Have you ever seen so many blue-legged hermit crabs in your life?’ ” Mr. Kehoe said.

While acknowledging that some collectors are aware of the dangers of overfishing, Dr. Rhyne said there had been little scientific study of the blue-legged crabs and the hundreds of other species that are collected, including the 15 that make up about 90 percent of the catch. For example, with certain snails it is not known how long it takes for them to start to reproduce. If it is more than a year, then harvesting many of them from the same location year after year could be disastrous. There are many species that are probably not a concern, Dr. Rhyne said, but he added, “I don’t think anyone can use the word ‘sustainable’ when they don’t know enough about the animals.”

What is not in dispute is that the fishery has changed in the past two decades, coinciding with the rise in popularity of reef tanks. These aquariums include home or office tanks of a few gallons to several hundred gallons or more, and attractions like the 20,000-gallon coral reef tank at Atlantis Marine World in Riverhead, N.Y., considered one of the finest anywhere.

Jeff Turner, owner of Reef Aquaria Design of Coconut Creek, Fla., which builds and maintains large reef aquariums in homes, offices, hospitals and other institutions, says these are not mere decorations, but “an educational window into the sea.” The hobbyists and professional aquarists who undertake these projects, he said, “are concerned about the marine environment.”

The popularity of the tanks is reflected in a study of Florida fishery data by Dr. Rhyne, Michael Tlusty, director of the New England Aquarium, and others. As the researchers detailed in a paper earlier this year in the open-access journal PLoS ONE, the number of organisms collected from 1994 to 2007 increased by about 13 percent a year, on average, to about 8.8 million in 2007.

Over the same period, the types of invertebrates changed. In 1994, only 6 species among the top 15 were collected and sold for their ecological roles as cleaners, grazers, water filters and the like. The others were harvested for their ornamental value — because they look pretty in an aquarium — or as curios to be sold in shell shops and other stores. The most popular “working” invertebrates were turbonella snails, with about 175,000 collected.

Thirteen years later, 9 species among the top 15 collected were sold to fill ecological niches in aquariums, including nearly 700,000 turbonella snails and 2.4 million blue-legged crabs.

“Now, there are whole suites of taxa that people don’t really care what they look like,” Dr. Rhyne said. “They only care that they perform these services that are exactly the same as they are performing in the wild.”

For example, Dr. Rhyne said, peppermint shrimp, of the genus Lysmata, are not as showy as some other shrimp species, but since they control a pest anemone in tanks, their harvested numbers have increased twentyfold in Florida since 1994. “There’s just a huge demand,” he said.

The attraction to the hobbyist or professional is that using these creatures both replicates the natural ecosystem and reduces the need for less-natural forms of tank maintenance. At Atlantis Marine World, Joseph Yaiullo, curator and co-founder, scuba-dives in the reef tank regularly to scrape algae off the glass or trim the many multicolored corals, some of which he has been growing for two decades. Yet he also has sea urchins — scavengers that do some of the cleaning.

“If I can put some critters in there that make my life easier, I’ll do it,” said Mr. Yaiullo, whose tank has inspired many a home hobbyist. “I’d rather have urchins scraping away than me doing it.”

Mr. Yaiullo does not use crabs or snails in his big tank, and the urchins he uses come from the Indian and Pacific Oceans, another source of invertebrates. His coral thrives so well that he is constantly removing pieces, or “frags,” which he provides to hobbyists on Long Island and elsewhere for home tanks. But home hobbyists are not always as skillful at maintaining their tanks, which are susceptible to even small changes in water chemistry or temperature. Invertebrates die, for natural or other reasons, and must be replaced.

“The thing that’s always bothered me is the disposable nature of these animals,” said Eric Borneman, a longtime aquarist who has written two books on coral husbandry and is studying for his doctorate in reef ecology at the University of Houston. With invertebrates, he said, “there’s a huge amount of mortality in shipping,” and in tanks kept by people just starting out in the hobby. “How do you stop this mortality and this constant influx of animals from the wild to supply this trade?”

Collectors and others argue that even with high mortality creating an even greater demand, the numbers of creatures harvested every year in Florida are still not a cause for major concern. They say their fishery is not like other commercial fisheries that harvest huge numbers of fish or shellfish for eating. And the invertebrate catch is closely monitored by the state, said Ms. McCawley, the Fish and Wildlife Conservation Commission biologist. “If we see an explosion in a particular species, then we can come back and revisit this at any time,” she said. “We feel these things are pretty well protected.”

Collectors point out that an unusual cold snap in January probably killed far greater numbers of invertebrates than are harvested each year. “Our biggest threat to this fishery is the changing conditions down here,” said Ken Nedimeyer, a longtime collector. “Our little collecting effort can’t even compare to a natural event.”

But Dr. Tlusty, of the New England Aquarium, said that in Florida “they are trying to manage this as a single fishery,” when there are hundreds of diverse species being collected, and about which not enough is known. While the state has done a much better job of managing its fishery than governments overseas, he said, “it’s probably time to go to a more adaptive management strategy.”

“Let’s make sure in our own backyard we’re doing things right.”

Dr. Rhyne added: “We’re not saying it’s going to collapse tomorrow or next year. But we need to do due diligence, so all of a sudden we don’t say, ‘Oops, we just caught the last one.’ ”