NANFA-- Releasing Non-Native Marine Fishes

Hoover, Jan J ERDC-EL-MS (
Wed, 7 Apr 2004 17:41:02 -0500


This press release will be of interest to marine hobbyists and to those at
last year's meeting who saw Fritz Rohde's video of lionfish swimming off the
coast of the Carolinas.

- Jan

FROM: Sandra Hines
(206) 543-2580
(NOTE: maps, researcher contact information at end)

For Immediate Release
April 7, 2004

Freeing Nemo
Aquarium owners releasing non-native fish could endanger marine ecosystems

Flushing your pet tropical fish to set it free is a bad idea. So is
releasing it at the beach.
Intentional and unintentional aquarium releases have been a leading
cause of freshwater fish invasions, but now researchers from the University
of Washington and the Reef Environmental Education Foundation have found 16
non-native species of fish - apparently set free from home aquariums - in
ocean waters off the southeast coast of Florida.
This is an unprecedented number of non-native marine fish in a
concentrated geographic area, says Brice Semmens, a UW doctoral student in
biology and lead author of a paper published in the journal Marine Ecology
Progress Series.
Using data on the aquarium trade and shipping traffic, the study is
the first to convincingly demonstrate that well-meaning pet owners can cause
a "hot spot" of non-native tropical marine fish, Semmens says. The 16
species were found in 32 different locales along the coast of Broward and
Palm Beach counties and in the upper Florida Keys. Some were in the Florida
Keys National Marine Sanctuary.
Most of the species were seen at more than one place meaning more
than just a few aquariums have been dumped, Semmens says. It is not clear
which, if any, of the non-natives have established breeding populations, he
The more times a species is released, however, the greater the
chance of establishment, says Walt Courtenay, fisheries biologist with the
U.S. Geological Survey in Gainesville, Fla., who is known around the world
for his expertise on exotic fishes. He is not a co-author of the published
"Typically, I'd say aquarium owners are more concerned with the
status of our marine ecosystems than the general public is, yet many appear
unaware of the potential pitfalls of releasing pets into the wild," Semmens
The study relied on information submitted by volunteer divers and
snorkelers through the Exotic Species Sighting Program of the Reef
Environmental Education Foundation, or REEF, based in Key Largo, Fla.
Sightings were confirmed with photographs, video or corroboration by other
The introduced species are native to the tropical western Pacific
and/or Red Sea. Emperor angelfish, with their blue masks and bodies striped
in blue and gold, were the most commonly sighted non-native species and are
imported by the aquarium industry in relatively large numbers. Indeed, the
researchers found a compelling correlation between how commonly ornamental
marine species are imported and how often they were sighted. Another
commonly sighted non-native was yellow tang, a bright yellow oval fish that
is the most commonly imported species of the U.S. aquarium trade.
In contrast, Semmens says it is unlikely the exotics arrived in the
ballast water of ships. If the fish were being introduced through ship
ballast, one would expect the native ranges of the fish to correlate to
where the ballast water comes from. Analyzing data on shipping traffic to
Florida ports, Semmens and his co-authors found no support for this
While only a small number of introduced species might have
devastating impacts, scientists are unable to predict which species will be
destructive. The largest set of intentionally released marine fish was
carried out in temperate coastal and inland seas of Russia in the 20th
century. Sixteen species became established, with ecologically and
economically devastating results, including harm to valuable fisheries,
parasite introductions and the endangerment and extinction of native
"Releasing non-native reef fish is like playing Russian roulette
with tropical marine ecosystems," Semmens says. Then, too, even if
introduced species do not have dramatic impacts, their presence is unnatural
and unwanted.
"Divers visit the reefs of Florida to see the region's natural
beauty and diversity. It is a unique and magical experience to dive on
these reefs. Adding new species to the region is comparable to adding a few
finishing touches to one of da Vinci's masterpieces."
Co-authors of the paper are Eric Buhle and Anne Salomon, both UW
doctoral students in biology, and Christy Pattengill-Semmens, science
coordinator for the Reef Environmental Education Foundation.
Aquarium keepers need to be educated about the proper disposition of
animals in their care, according to Paul Holthus, executive director and
president of the Marine Aquarium Council, an international non-profit
organization based in Honolulu that focuses on the way tropical fish are
collected and handled before they are purchased.
"While it is against the law to release non-native marine fish into
coastal waters, it's a problem that can't easily be policed," Semmens says.
The authors say that education programs for dealers and aquarists could
curtail exotic species introductions if implemented properly. Such programs
would need to highlight the problems of introduced species and provide ways
for aquarium owners to sell or trade unwanted fish.

- For more information: Semmens, (206) 529-1240,
- "A Hotspot of Non-native Marine Fishes: Evidence for the Aquarium Trade as
an Invasion Pathway," Marine Ecology Progress Series, vol. 266, Jan. 30,
- Reef Environmental Education Foundation's Exotic Species Sighting Program,
- Holthus, (808) 550-8217,, Marine Aquarium
Council, see

Image available for news media use only
Emperor angelfish, imported by the U.S. aquarium industry in very large
numbers, were the most commonly sighted non-native. Photo credit required:
Paul Humann

Sightings of non-native marine fish along southeastern United States include
lionfish, in the news after they started being caught by recreational
fishers. Along Palm Beach and Broward counties, Fla., 16 non-native species
- apparently set free from home aquariums - were sighted. Map credit
required: University of Washington/Reef Environmental Education Foundation
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