Lionfish spreading in a way no other species ever has

Adult lionfish uses its fins to herd smaller fish into compact areas where they are eaten. Photo: Photos by James Morris, Jr. of the National Oceanic and Atmospheric Administration

The rapid spread of lionfish along the U.S. eastern seaboard, Gulf of Mexico, and Caribbean is the first documented case of a non-native marine fish establishing a self-sustaining population in the region, according to recent U.S. Geological Survey studies.

“Nothing like this has been seen before in these waters,” said Pam Schofield, a biologist with the U.S. Geological Survey’s Southeast Ecological Science Center in Gainesville, Florida. “We’ve observed sightings of numerous non-native species, but the extent and speed with which lionfish have spread has been unprecedented. lionfishes pretty much blanketed the Caribbean in three short years.”

The fish are common along the Caribbean coast of Costa Rica.

A group of juvenile lionfish

More than 30 species of non-native marine fish have been sighted off the coast of Florida alone, but until now none of these have demonstrated the ability to survive, reproduce, and spread successfully. Although lionfish originally came from the Indo-West Pacific Ocean, there are now self-sustaining populations spreading along the western Atlantic coast of the U.S. and throughout the Caribbean.

It is not yet clear exactly how the new invasive species will affect reefs in this part of the world. Foremost on the minds of scientists is the lionfish predatory behavior, which may negatively impact native species in the newly invaded ecosystems. They have already been observed preying on and competing with a wide range of native species.

Invasive lionfish were first reported off Florida’s Atlantic coast in the mid-1980s, but did not become numerous in the region until 2000. Since then, the lionfish population has rapidly spread north through the Atlantic Ocean and south throughout most of the Caribbean. The spreading population is now working its way around the Gulf of Mexico.

Dr. Schofield spent years compiling and verifying sightings of lionfish, reaching out to local experts such as biologists, museum curators, natural resource managers, divemasters and citizens groups to collect detailed records of specimen collections and sightings throughout the region.

No one knows for sure exactly how the predecessors of the current population first made it into the Atlantic and Caribbean, but Dr. Schofield believes the invasion serves as a warning of the dangers posed by introductions of non-native fish into an ecosystem.

“This invasion may constitute a harbinger of the emerging threat of non-native marine fishes to coastal systems,” Schofield said.

Eradication of lionfish is probably not possible, admits Dr. Schofield. Yet, local control efforts may be able to keep the population tamped down, releasing pressure on the native ecosystem.

Many Caribbean countries such as Bermuda and the Cayman Islands have begun lionfish control programs.

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