Lionfish populations continue to expand in coastal waters of the Atlantic Ocean and the Gulf of Mexico, stretching from New England to Mexico.
The exotic invader from the South Pacific and Indian Ocean was first documented off South Florida in 1985 after someone dumped his or her aquarium in the ocean rather than disposing of the lionfish.
Nothing was done about those fish by state or federal agencies. By the 1990s, lionfish had spread along Florida’s Atlantic coast. In 2000, they showed up off North Carolina. In 2009, lionfish had expanded throughout the Florida Keys. From there they stretched along the Gulf coast to Mexico.
In addition to the United States, the fish, which gobble up native reef species, have spread throughout the Caribbean to Central and South America. The Keys-based Reef Environmental Education Foundation has excellent information about lionfish on its website at www.reef.org/lionfish.
Now, thanks to a science fair project conducted by a 12-year-old girl from Jupiter, Fla., there is new information. It’s not good.
Scientists say that lionfish can also spread into estuaries with extremely low salinity rates. That means lionfish, which have no predators in their new range, could establish a stronghold in bays, lagoons and rivers with just a hint of saltwater.
In Florida, the fish already have been documented in the Loxahatchee River in Jupiter and the Indian River in Sebastian. The thinking was that the fish couldn’t stray too far from the inlets connected to those rivers, but Lauren Arrington discovered otherwise.
Arrington’s sixth-grade project demonstrated that lionfish can survive in water that is almost fresh. Scientists who heard about her project replicated her work and confirmed just how tolerant of low salinity levels lionfish can be.
“Her project was the impetus for us to follow up on the finding and do a more in-depth study,” said Craig Layman, an ecology professor at North Carolina State University, who was researching lionfish in the Loxahatchee River with graduate students from Florida International University.
“We were the first paper that published the salinity of the lionfish, and it was all because of what she had done with her science project.”
For her project, Arrington gradually lowered the salinity in five aquariums with lionfish that she and her father caught in the Indian River. They kept another aquarium at normal ocean salinity level of 35 parts per thousand as a control. Arrington brought down the salinity levels to 6 parts per thousand and the lionfish were fine. She didn’t go any lower for fear of killing the fish, which would have disqualified her project from the science fair.
Layman and his graduate students found that lionfish can tolerate a salinity of 5 parts per thousand, as well as pulses of fresh water. Their findings were published in “Environmental Biology of Fishes.” Arrington received a mention in the research paper’s acknowledgments section.