Chasing the lionfish: FIU researchers find predator in troubling waters

The invasion has reached the Loxahatchee River.

Lionfish, native to oceans halfway around the world, have reached the estuary near Jupiter, threatening the local ecosystems.

Researchers at Florida International University have discovered the foreign predator, an invasive species originally from the Indo-Pacific region, nearly three miles inside the Loxahatchee River.

The inlet is of particular importance, FIU researchers say, because of the dozens of native species of juvenile fish that utilize the river as a nursery before making their way to coral reefs and other marine habitats.

“The presence of the lionfish inside the estuary is pretty striking,” said FIU Marine Sciences Professor Craig Layman, who specializes in tracking the fish. “This represents a totally new dimension of the lionfish invasion.”

The appropriately named lionfish, with its red stripes and elaborate venomous spines, was first discovered off the cost of Dania Beach in 1985. Scientists believe that through the aquarium trade, the species began spreading along the coast of Florida and the east coast of the United States, eventually crossing the Gulf Stream in 2005 into the Bahamas and Caribbean. Lionfish can now be found as far west as Louisiana and as far south as Venezuela.

Researchers from the University of North Carolina, in conjunction with Layman, also discovered that, because it is relatively new to the area, other fish still don’t recognize it as a predator, approaching it without fear. Similarly, other predators don’t see the lionfish as food. With no enemies and abundant naïve prey, as well as rapid reproductive abilities, lionfish have spread throughout the region.

Indeed, the presence of a single lionfish has been reported to reduce small fishes on patch reefs by about 80 percent in a five-week period, Layman said. Fish most vulnerable to this striped predator include parrot fish, damselfish and surgeonfish.

The lionfish’s invasion of the Loxahatchee River adds a new concern.

“It’s pretty phenomenal to find this fish inside the estuary,” Layman said.  “I can’t think of any fish you would commonly find in a foot of water as well as depths of 1000-feet.”

But what if we became their predators?

“Lionfish are delicious to eat,” Layman said. “If a local market could be created for lionfish, the population could be controlled locally.”

The recently-published findings, written by FIU doctoral candidate Zachary R. Jud, can be found here.