If you have a dentist with a tropical reef tank in her waiting room, then you have likely seen Red Lionfish (Pterois volitans, Pterois miles, also known as zebrafish) in all their flamboyant glory. The striking reddish brown and white zebra stripes, amazingly long pectoral and dorsal spines (up to 18 of them), and the face of a surprised curmudgeon, make them fun to observe in the aquarium tank as they wobble back and forth in a slow sashay.
It was in 1985 that the first lionfish were sighted in the Atlantic, just off the South Florida coast. They must have been released by accident or aquaria enthusiasts who could no longer keep them. They are voracious eaters, and expensive to maintain. There is no other explanation for their presence so far from their native reef habitats in the South Pacific. In fact, genetic screening by the US Geological Survey (USGS) and the Reef Environmental Education Foundation (REEF) of Key Largo, has determined that the release of about nine fish was all it took to incite the worst invasive species disaster on the Atlantic coast, Bermuda and the Caribbean, Latin America, and the Gulf of Mexico.
Since the late 1990s the USGS has kept a detailed map of confirmed sightings, which are getting easier all the time because this fish, most commonly seen at 10-20 cm in length, has ballooned to more than half a metre in size, gobbling up all the gullible Atlantic coast reef fish—naive in their defences against its sudden deadly attack. Lion fish were not in their evolutionary script.
Victims of any size, even up to twice the size of the lionfish, are ambushed with ease, speared with a toxic tine, sucked into the maw and swallowed whole, leaving the digestive juices to break down the stomach contents. And this can be quite a job since the stomach of a lionfish can expand up to thirty times in size!
Stephanie Green, a Marine Ecologist from Simon Fraser University, has been working in Key Largo with Lad Akins of REEF, to study the impact the lionfish are having on the local reef habitat. Dissection of a specimen about a foot long reveals that even when the stomach is chock full of partially digested prey, it is not the largest of the internal organs. Far more massive in the female lionfish are the two ovaries, each about the size of a flattened chicken’s egg, with 30,000 eggs in each.
In their native range, lionfish populations are controlled by many factors such as predation, competition, and disease. In the Atlantic Ocean, they have few if any natural predators and they are relatively resistant to parasites. The ecological scales are tipped even further in their favour by the fact that, into this virgin territory, the well-fed females are capable of producing 60,000 eggs every 3-4 days year-round! For these reasons, the lionfish invasion in the North Western Atlantic and Caribbean represents one of the most rapid marine invasions in history.
A recent study found a tenfold increase in their abundance from 2004 to 2008 in parts of the Atlantic and Caribbean. More detailed recent REEF estimates of lionfish abundance have reported more than 200 lionfish per acre in some locations. When lionfish are introduced experimentally into a new area, survival of native reef fishes decline by about 80-90 percent. In one study, during a five week period, net accumulation of intentionally placed larvae of native species was reduced by 80% on reefs with a single lionfish present. These introduced tropical fish are eating their way both up and down the Atlantic coast.
One factor explaining the steadily increasing range of this invasive species is warming Atlantic Ocean temperatures in the Gulf Stream. As the effects of extreme warming in the Arctic melt the ice and amplify more extreme weather conditions in North America, they accelerate the defrosting of carbon-rich permafrost, which releases CO2 and methane that each cause faster warming in a dangerous amplifying feedback.
What happens in the Arctic does not stay in the Arctic, and the lionfish are feeling more and more adaptive to the warmer Atlantic temperatures farther and farther north. In the summer months they are found as far north as Boston and New York. And the cost to the Atlantic fishery is high.
The aggressive feeding behaviour of the lionfish impacts multiple trophic (vertical) levels by reducing the abundance of herbivorous fishes that keep seaweeds and large algae from overgrowing corals. The biological balance is now completely upended because lionfish occupy the same trophic position as economically important species such as snapper and grouper, spiny lobster, wrasses, parrotfish, blennies, and any juveniles of any other species. In addition, their presence may hamper all the stock rebuilding efforts and coral reef conservation measures humans have been taking. But all may not be lost.
With Atlantic coast fisheries under an exponentially increasing threat from the lionfish takeover, Florida Keys National Marine Sanctuary and REEF began to sponsor lionfish derbies to raise public awareness, remove lionfish from the sanctuary, and highlight the fact lionfish can be safely prepared and consumed by the public. And turns out, they are delicious.
The 2015 SeaWeb Seafood Summit used the theme “Malicious but Delicious!” in its Celebrity Chef Lionfish Challenge, and this event, hosted by renown chef, Barton Seaver, brought elite chefs from Charleston and New Orleans to Houston and Washington, DC, for a confluence of convivial cookery that made this fish user-friendly. Seafood and sustainability is the rudder that steers SeaWeb, and restaurants, chefs, fish retailers, and everyone involved in the care and development of the marine food industry, is committed to shaping fish consumption around sustainability practices. Those practices now include eating lionfish.
Seaver is a firm believer that human health depends on the health of the ocean and that the best way to connect the two is at the dinner table. Esquire magazine honoured Seaver as 2009 Chef of the Year, and his restaurant Hook was named by Bon Appétit magazine as one of the top ten eco-friendly restaurants in America. This man knows fish. His recipes for lionfish are now part of his repertoire.
The New York Times recently dubbed people who eat invasive species to save native ones, “invasivores,” officially making the movement trendy. So don’t be surprised to find lionfish on the menu.
Paul Greenberg, author of the 2010 best seller Four Fish: The Future of the Last Wild Food, has encouraged the Caribbean tourist-dive industry to make this a destination-mission, since only scuba divers with spears are able to find these fish hiding in the reef nooks and crannies. The rewards are gustatory, ethical, and a good day in the water.
Publisher’s Note: Judith Stapleton is a writer in the fields of science and medicine.