http://www.sun-sentinel.com/news/lo...9apr09,0,6085919.story?coll=sfla-news-broward
By David Fleshler
Staff Writer
Posted April 9 2004
Thousands of miles from their homes in the Pacific Ocean, Indian Ocean and Red Sea, 16 species of non-native tropical fish have been spotted in the waters off southeast Florida.
Most likely released by aquarium hobbyists, these fish could constitute a potential threat to native fish and other marine life, according to an article in the journal Marine Ecology Progress Series.
Volunteer divers have repeatedly spotted emperor angelfish, yellow tangs, lionfish and other species that are imported into the United States for home aquariums. No one knows whether any have established breeding populations off the Florida coast, but scientists and state officials say the introduction of these outside species could risk dislocating entire ecosystems.
Lacking natural predators or competitors, non-native species can wipe out fish or plants that never had a chance to evolve defenses. They can introduce parasites or diseases. They can thrive at the expense of native species, as non-native melaleuca trees did when they swarmed over the sawgrass prairies of the Everglades.
"You're setting in motion a chain of events where you don't know the outcome," said Scott Hardin, exotic species coordinator for the Florida Fish and Wildlife Conservation Commission. "It might be benign, or it could be malignant. I don't think anybody has a handle on the ecological implications of aquarium fish. Right now the science is in the earliest stages of discovery."
It's illegal to release non-native wildlife in Florida, but many people don't know that and the law is obviously difficult to enforce.
A study, which was peer-reviewed, was conducted by graduate students at the University of Washington, along with a member of the Reef Environmental Education Foundation. They studied thousands of reports from volunteer divers in the Caribbean, Gulf of Mexico and southeastern United States, whose work was coordinated by the Reef Environmental Education Foundation. They found that the hotspot for non-native tropical fish was the stretch of ocean from West Palm Beach to Fort Lauderdale.
"We found that the vast majority of the non-native fishes we were seeing were showing up off of Palm Beach and Broward counties, Florida," said Brice Semmens, the lead writer of the article. "Some we were seeing as far south as Key Largo, but it was really clear after looking at the data that there was kind of a hotspot."
The other non-native fish seen were the panther grouper, raccoon butterflyfish, orbicular batfish, blue-ringed angelfish, Arabian angelfish, yellowbar angelfish, semicircle angelfish, Moorish idol, orangespine unicornfish, sohal surgeonfish, yellowtail sailfin tang and two other types of sailfin tang.
Semmens wasn't sure why these two counties had the most non-native fish. But it could be that the region combines the right climate and habitat with a high population, which means a lot of tropical fish collectors. The environment and water temperature of South Florida is certainly more similar to these fishes' native habitat than the waters off New Jersey or North Carolina. The study examined the two most likely ways the tropical fish reached Florida: from home aquariums or through ballast picked up by ships arriving at local ports. They reviewed the routes of ships and their ballasting records. They analyzed import and export data on aquarium fish. And they analyzed more than 49,000 survey forms completed by divers.
Their analysis found that home aquariums were the most likely source of the exotic fish swimming around the Florida reefs. Semmens said he thinks the fish come from well-meaning hobbyists trying to dispose of unwanted fish in the most humane way they can think of -- without being aware of the potential impact on the environment.
"I like to believe people care about their pets," he said. "I think they're releasing them because they think their aquariums are too small to give their pets a good life, or because they have empathy for their fish and they want to release them and let them be free in the wild."
Paul Holthus, president of the Marine Aquarium Council, a non-profit group that promotes conservation-oriented practices in the aquarium business, said the study showed the importance of educating hobbyists about the most ethical ways to deal with unwanted fish. This could best be done through retailers, since they're the ones most likely to be in contact with hobbyists.
"The real issue is that hobbyists have a responsibility for the proper care of their animals," he said, speaking from the group's branch office in Fiji. "We really believe it's a serious issue, and hobbyists have a responsibility to be informed and act responsibly."
David Fleshler can be reached at dfleshler@sun-sentinel.com or 954-356-4535. Email story
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