Lionfish Invasion Spreads
From Microcosm Aquarium Explorer
- Common Lionfish, Pterois volitans, on Indo-Pacific reef. Scott W. Michael
- Miles Lionfish, Pterois miles, off US coast. NOAA
- NOAA divers catching lionfish off North Carolina. NOAA
- Juvenile Pterois volitans caught off Long Island, NY. Image © Todd R. Gardner
Indo-Pacific native finds a new Western Atlantic Home
The battle to stop the invasion of Indo-Pacific Common Lionfish (Pterois volitans and the similar Miles's Lionfish (Pterois miles) in western Atlantic waters appears to be lost.
The most-recent map of lionfish sightings from the US Geological Survey shows a spreading rash of red dots that stretches from Jamaica and Cuba to Rhode Island, with numerous reports from the coasts of Florida, Georgia, the Carolinas, Bermuda, and the Bahamas.
Carried by the warm, powerful Gulf Stream that sweeps up the eastern seaboard, significant numbers of lionfish are reportedly arriving in the temperate waters of Long Island each summer, although it is unlikely they are able to overwinter in northern climates.
In numerous locations along the US coast, lionfishes are being spotted on shipwrecks and over hard bottoms, at depths of 80 to 260 feet. Anglers have reported catching lionfish as large as 17 inches on hook and line.
According to NOAA, it is the first known instance of a tropical western Pacific fish species successfully implanting and breeding in US waters.
Tracing the Plague
Investigators for NOAA (the National Oceanic and Atmospheric Administration) say that no single smoking gun has been found, although the color patterns seen in the growing Atlantic population of lionfish are similar to those common in fish collected in the Philippines for the aquarium trade.
There are, in fact, multiple suspected or possible sources:
- A group of six Volitans lionfish accidentally released in Biscayne Bay, FL, when an oceanside aquarium burst during Hurricane Andrew in 1992.
- A large casino aquarium in the Bahamas is known to have kept lionfishes in an open system, in which eggs and/or larvae could have been flushed into the sea. (An open system uses a natural source of water to flow through a display aquarium or propagation system.)
- Unsubstantiated reports suggest that an unscrupulous dive operator may have planted a population of lionfish at a site off the Carolinas to create an unusual destination for his clients.
- It is possible that larvae or juvenile Pterois specimens may have been released in the ballast water of one or more ships.
- Releases of individual lionfish by home aquarists may have contributed to the creation of a successful breeding population.
A River of Lionfish
Scientists point to the powerful sweep of the Gulf Stream as the likely vector of the rapid lionfish dispersal.
“Dispersal of the lionfish population along the Atlantic coast was likely helped by Gulf Stream transport of lionfish eggs and larvae,” said Jonathan Hare, co-author of an early NOAA assessment report. “Adult lionfish have been found primarily in water depths of 85 to 300 feet, and juvenile lionfish have been observed in North Carolina, Bermuda and as far north as New York in shallow coastal waters.”
The first documented report of a lionfish juvenile being caught in the Atlantic came from Todd R. Gardner, then a marine biology graduate student at Hofstra University. On a field trip to the south shore of Long Island on September 16, 2001, Gardner found a single Pterois volitans juvenile approximately one inch in length, proof that the species was reproducing in western Atlantic waters.
Now an aquarist at Atlantis Marine World, Gardner has created an exhibit of locally-caught lionfish and continues to document the arrival of Pterois juveniles in American waters each summer. See: Altantic-Bred Lionfishes.
Here to Stay
Whatever the source or sources, NOAA says that this particular genie is probably permanently out of its native bottle. Even though slow-swimming and easy to catch, the fish are now so widespread that eradiction efforts are not likely to be successful.
"It is unlikely that the lionfish's invasion of U.S. waters can be reversed," says NOAA. "Any large-scale attempts to remove the existing lionfish from U.S. Atlantic waters appear impractical and would be very costly, because of the large geographic range and depths that the fish now occupies." (One collection effort by NOAA in 2004 off North Carolina netted 155 lionfish.)
NOAA's current impact assessment, from their website, is not positive: "Lionfish also are believed to pose particular risks to the local environment. They are voracious predators that feed not only on small shrimps but also on large fish, perhaps including the young of important commercial fish species such as snapper and grouper, many of which use the region’s “live bottom” reefs as nursery grounds. The invasive lionfish have few if any natural predators in their new Atlantic environment."
Three of agency’s divisions—the NOAA Ocean Service, NOAA Fisheries and NOAA Research—are working together through research and public outreach to deal with the lionfish threat. Reef.org has a volunteer invasive species spotting program in place, coordinated with NOAA.
What you can do:
- Never release aquarium livestock (fish, invertebrates, plant matter) into local waters. (Here's a Florida media solution: Ban the Sale of Lionfish. Read more...)
- Check out Reef.org and its "Exotic Species Sighting Program:" REEF
- Scuba divers and others can help with the NOAA research effort by reporting lionfish sightings to:
Paula Whitfield NOAA Beaufort Laboratory 101 Pivers Island Rd Beaufort, NC 28516 -9722
Voice: 252-728-8746 Fax: 252-728-8784 Email: [email protected]
Please be prepared to provide coordinates of where the lionfish was found and at what depth. If possible, photographs or video should accompany the above information.
References:
[Advanced Aquarist's Online Magazine Article by Todd R. Gardener: Atlantic Lionfish?]
Further Reading
Credits Map provided by the US Geological Survey, with thanks to: Pam Schofield
Gulf Stream Imagery: NOAA