Lionfish Invade U.S. Waters

The red and black dots are locations in the Atlantic Ocean where lionfish have been reported as of May 2003. Click on image for larger view and further details.

Local divers off the coast of North Carolina were not expecting to see what they found one day in August 2002--the exotic and beautiful lionfish, common to the warm waters of the western Pacific, but unknown at that time as residents of the Carolina coast. They provided the first solid evidence that lionfish were in the Atlantic--an actual specimen that they collected. A year later, scientists had documented 19 lionfish sightings at eight locations along the North Carolina continental shelf. By then, lionfish were also being observed off the coasts of Florida, Georgia, and South Carolina. Juvenile lionfish were also showing up off Bermuda and even as far north as Long Island, New York! Since then, many more United States divers have reported sightings of the distinctive fish. Between 2000 and 2003, 49 lionfish sightings were reported at 16 different shipwrecks and natural hard bottom locations. During a summer 2004 research expedition, NOAA scientists collected 155 lionfish at 19 different locations off the North Carolina coast alone. The jump in numbers and distribution over such a short time, plus sightings of juveniles smaller than those sold for aquaria, strongly indicate that the lionfish is reproducing in the Atlantic Ocean. If this is true, it's the first time that a western Pacific fish has populated the waters of the U.S. Atlantic coast.

The warm Gulf Stream current (in red) may have dispersed lionfish as far as North Carolina and Bermuda, where water temperature is similar to their native habitat. Lionfish larvae may have been carried in the Gulf Stream to the northeast in a similar way.

How did lionfish get into the Atlantic Ocean?

Reportedly, six lionfish were accidentally released in Biscayne Bay, Florida, when a beachside aquarium or nursery broke open during Hurricane Andrew in 1992. It's likely that even more have been released on purpose when people no longer want them as aquarium pets because they grew too large for the aquarium, or they learned the hard way that lionfish will eat their other fish! The swift and warm Gulf Stream, which likely transported buoyant lionfish eggs and larvae from Florida northward, helped the lionfish's Atlantic journey.

It's pretty unusual for non-native, tropical marine fishes, like the lionfish, to establish themselves at this latitude. In Florida waters and along the continental shelf near the Gulf Stream the temperatures are very similar to the lionfish's native waters.

Lionfish swimming near the wreck of the Cedar Pride , a Lebanese freighter purposely sunk in 1986. This popular dive site is located in the Sea of Aquaba, which is in the northern part of the Red Sea (Jordan). Click on image for larger view and further details.

However, from north Florida upward, the waters along the coastline are too cold in the winter for lionfish to survive. Scientists expect them to survive the winter only at water depths greater than 120 ft because this is where the Gulf Stream has influence all year long. Very importantly, the types of predators and competitors present in the marine community in the Atlantic are very different from the native range of the lionfish. These are a couple of the reasons why scientists are paying so much attention to the lionfish invasion. Generally, species like the lionfish have not been perceived to pose a significant threat to marine ecosystems because they were not likely to survive long. Research on this topic has been minimal, however, so it is hard for scientists to answer questions such as:

• Is this new discovery a cause for concern?

• Should something be done about it?

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