A recently released study of lionfish in the Florida Keys paints a bleak picture, as their population has increased sixfold in the course of a year.
However, the report does show how dive operators and recreational divers are keeping the invasive species from getting a foothold on local wrecks by targeting them with pole spears and spear guns.
In 2010, researchers estimated there were 89,000 lionfish in Keys waters. By the end of 2011, those estimates jumped to 335,000 fish, which is likely a conservative estimate since lionfish hide in the reef, said Ben Ruttenberg, fishery biologist with National Oceanic and Atmospheric Administration (NOAA) Fisheries.
For the first time since lionfish were spotted in the Keys, Ruttenberg and NOAA Fisheries have documented their population explosion throughout the Florida Keys National Marine Sanctuary. Scientists are now able to determine how quickly the invasive species is multiplying, according the September edition of the Bulletin of Marine Science.
Lionfish have been present in low numbers along the east coast of Florida since the 1980s, but were not reported in the Florida Keys until January 2009. Since that time, the average size of lionfish also has increased, the study states. Scientists expected lionfish to eventually appear and increase in abundance in the Keys, but the rate of increase is both surprising and alarming, according to the report.
"The invasion is happening quickly and progressing rapidly," said Ruttenberg.
Lionfish are voracious predators and are likely impacting native species, disrupting the ecology of the area they invade, Ruttenberg said. Lionfish have no natural predators in their invaded range in the Caribbean and Atlantic.
While the report illustrates a grim future, it shows how spear fishermen are helping to control the populations in a limited way. Artificial reefs were the only habitat category that did not see an increase in lionfish population between 2010 and 2011, the report states.
"Many recreational divers have begun carrying lionfish-removal devices such as small spears, which may partly account for the lack of increase in frequency of occurrence between 2010 and 2011 in this habitat," the report states.
One of those divers is Jason Ward, a dive master with Lost Reef Adventures in Key West. Ward's record for lionfish on the Vandenberg artificial reef is 14 in five minutes, he said. His two day record on the wreck is 24. However, he said the fish seem to be getting smarter and have begun to hide deeper in the wreck and surrounding area.
Sanctuary officials have not been shy in saying there is no closed season, no bag limit and no size limit for lionfish. The sanctuary, along with Reef Environmental Education Foundation (REEF), has conducted lionfish derbies in the past two years.
Key West Dive Master Randy Pekarik has watched the lionfish population explode on some of the deeper wrecks -- those not obtainable by many divers as they are at depths greater than 150 feet.
In 2010, Pekarik dove the USS Curb off Key West and did not see any lionfish. He dove it again six months ago and the wreck was "loaded" with the species.
"They were so thick I thought I was going to get stuck [by their venomous barbs]," Pekarik said. "They need to come up with a comprehensive plan to eradicate these."
But NOAA officials don't see that happening.
There simply will "not be enough divers to control the lionfish population," Ruttenberg said.
Keys commercial trap fishermen and restaurants are also doing their part to get the lionfish off Keys' reefs and onto people's dinner plates.
In the past year, Conch Key-based commercial lobster fisherman Gary Nichols and others have been selling lionfish to several Upper Keys restaurants. The taste and texture has been likened to that of hogfish or snapper.
Nichols has been known to bring home as many as 100 pounds of lionfish a day, selling it for $6 a pound. He has earned the nickname, "The Lion King."
Nearly all of the traps that are in water deeper than 140 feet have at least one lionfish inside, he said. Nichols' main clients are Lazy Days restaurant in Islamorada and The Conch House in Key Largo. He said they take as many as he can bring in.