Associated Press

Coral reef fish imported to the United States for saltwater aquariums are more diverse yet less numerous than previously thought, a new study suggests.

The study, published in the journal PLOS One, found that fishes comprising 1,802 species from 125 families were imported into the United States over a yearlong study period. Previous estimates of diversity based on government import forms were 22 percent lower.

Yet only about 11 million individual marine fish were imported, not the 15 million indicated on declaration forms.

It’s the “onesies and twosies,” the species found in only a few tanks, that are most interesting, Andrew Rhyne, the lead researcher and a marine biologist at Roger Williams University and the New England Aquarium, remarked in a telephone interview.

Nonetheless, 52 percent of the fish imported during the study period were from only 20 species, the study found. And damsels and anemone fishes from the Pomacentridae family made up half of the top 20 species and about three-quarters of the individuals.

The international trade in colorful marine organisms from coral reefs has become big business over the past 15 years. New lighting and filtration technology enabled hobbyists to set up saltwater aquariums at home, and the popular 2003 movie “Finding Nemo” buoyed demand for clownfish. According to the federal Fish and Wildlife Service, one million of the world’s 1.5 million aquarium hobbyists live in the United States, and Americans buy more than half of all marine aquarium fish sold globally.

Until now, little has been known about these imports. To gather hard data, Dr. Rhyne recruited a team of students to examine more than 8,000 shipment declarations and corresponding invoices provided by the National Oceanic and Atmospheric Administration and the Fish and Wildlife Service dating from May 2004 to May 2005.



The researchers spent 6,000 hours entering the relevant information into a database. The least legible invoices, often either handwritten or sent as low-resolution faxes, were entered manually, and a customized scanning program was used for the high-quality copies.

The invoices showed that while 40 countries export marine tropical fish to the United States, two countries — the Philippines and Indonesia— accounted for more than 86 percent of the trade. Sri Lanka and Haiti were the third- and fourth-largest exporters to the United States, respectively, although the data predates the devastating 2010 earthquake that killed an estimated 316,000 people and left Haiti’s capital, Port-au-Prince, in rubble.

Haiti is the only Caribbean country that has not established a marine protected area where fishing is restricted. Last year, the nonprofit organization Reef Check called the country’s coral reefs, once a destination for scuba divers and long fished for food, “the most overfished in the world.” Dr. Rhyne said that Haiti has been largely overlooked as a major source of ornamental marine fish in the global trade.

The invoices revealed that 1,802 reef fish species from 125 families were imported that year. Previous estimates based on government import forms were significantly lower: just 1,472 species from 50 families. However, the invoice records also suggested the total volume of fish had been significantly overestimated on declaration forms (at 15 million, versus the 11 million reflected on the invoices).

“We were pretty stunned by the error rate on those declarations,” Dr. Rhyne said. “Lots of things were being called marine fish that are not marine fish, like goldfish from Thailand. It looked like Singapore and Thailand were shipping a lot of marine fish to the United States, which they’re not. They’re shipping a lot of freshwater fish.”

In fact, only 52 percent of commercial invoices matched the government import forms.

The error rate may not be as alarming as it seems, Dr. Rhyne said. Fish and Wildilife inspectors do have the invoices in hand at the point of inspection, he said. The discrepancies really only matter when scientists use the government database to analyze the trade, he explained.

Still, the study raises flags on how ornamental marine fish imports are monitored and assessed. “I think the reason you see the errors is there’s no reason for that number to be accurate — unless they’re just following good business practices,” Dr. Rhyne said. “There’s virtually no regulations on fish right now on what’s coming in.”

The need for reliable import data is only increasing, the researchers write, as coastal managers seek to reduce risks from the introduction of diseases and invasive species. The current system maintained by the Fish and Wildlife Service tracks shipments based on the requirements set under the international treaty known as Cites, the Convention on International Trade in Endangered Species.

The database maintained by the service helps regulators determine the budget and staffing levels needed at various ports to inspect and document the incoming shipments.

Yet endangered species make up only a small portion of the market. The millions of fish that are not listed under Cites are entered into the system with only a general code for Marine Tropical Fish. As a result, Dr. Rhyne said, the system is a poor source of data on the trade of biodiverse wildlife.

Most of the fish imported for saltwater aquariums are small, numerous and widely distributed tropical species, Dr. Rhyne said. Yet the invoices show that imports for hobbyist aquariums also include some troubling species, for example, fish that can grow to six to eight feet in length as adults.

“They’re being sold as small fish as juveniles,” he said. But then, it may turn out that the fish is a giant grouper.

“Really, they probably don’t belong in the hobby,” Dr. Rhyne said.