Lionfish must be culled to prevent major reef impacts
By Lad Akins
While there are multiple sides to every issue, there are some very convincing arguments supporting removal of lionfish from Atlantic waters. Before we get into the detailed reasons, we should understand this is not a natural migration of lionfish into a new area, rather an introduction caused by man. Lionfish are extremely popular aquarium fish, and the same reasons that make them a burden to keep –– ravenous feeders with venomous spines –– position them to be perfectly suited as invaders in Atlantic and Caribbean waters.
Based on the recent work of Reef Environmental Education Foundation and researchers James Morris, Stephanie Green, Mark Hixon and others, we know that lionfish in the Atlantic: grow quickly, reaching maturity at less than a year of age; reproduce year-round with up to 30,000 eggs per spawning event (every four days); eat almost any prey that will fit in their mouth (up to half their own body size); feed on commercially and ecologically important species including grouper/snapper, parrotfish, cleaner species; have few if any predators in the Atlantic; and are reaching incredible densities up to 20 times higher than similar-size native species. The bottom line is that they are out-competing our native fish and consuming them at unsustainable rates.
Invasive species are the primary cause of extinction of other organisms, surpassing even human impacts. Could lionfish cause extinction of our native species? We can’t be sure, but the scenario is likely and once it happens it will be too late to reverse the change. And what of the consequences of those losses? If cleaner species –– which have been found in lionfish stomachs –– are impacted, we will likely see cascading effects through the rest of the fish community. If commercially valuable species like grouper and snapper are impacted, the effects will also reach local economies and communities through diminished fisheries and food supplies. If parrotfish and other algae eaters are impacted, the effects on corals themselves will likely be significant. Will equilibrium eventually be reached? Absolutely, but what will the system look like and are we willing to live with those consequences?
We can paint a dramatic and scary picture from what we now know. What we cannot yet predict, though studies are addressing this now, is how effective we can be in controlling lionfish populations and minimizing impacts. Tagging work led by REEF has shown very high site fidelity in lionfish –– they tend to stay put as long as there is food and shelter. This makes them a perfect candidate for removal. What we don’t yet know is how much effort will be required to remove lionfish and how many lionfish a reef can sustainably support. In addition, novel control methods are currently being explored that could provide efficient means of removal. The best part of removal? Lionfish are a very good eating fish. Combining removal efforts with the development of commercial use and markets can prove to be a win-win situation, which rarely occurs in invasive species scenarios. Programs are already in place or being developed in the U.S., Bermuda, Bahamas, Turks and Caicos and Cuba to encourage lionfish consumption. As those in Bermuda say, “Eat ’em to beat ’em!”
Finally, for all of the divers who love watching fish: Yellowheaded jawfish, fairy basslet, saddled blenny, slender filefish, belted cardinalfish, Nassau grouper, silversides, longsnout seahorse, striped parrotfish, octopuses, Spanish hogfish, bluehead, blue chromis, peppermint basslet, and more have all been found in lionfish bellies. Unless we’re willing to lose our favorite fish, lionfish will have to be controlled.
Lad Akins is the Director of Special Projects at REEF (http://www.scubadiving.com/sites/all/modules/elf/elf.png); background-attachment: initial; background-origin: initial; background-clip: initial; background-color: initial; padding-right: 12px; color: #14495a; font-size: 11px; font-weight: bold; text-decoration: none; background-position: 100% 50%; background-repeat: no-repeat no-repeat;" title="www.REEF.org" href="http://www.reef.org/">www.REEF.org). His focus is researching and controlling impacts of marine invasive species and continues to lead collaborative REEF projects addressing the lionfish invasion in Atlantic waters.
Culling lionfish doesn’t improve nature
By Matt Chew
There goes the neighborhood! They’re strange. Ugly. Dangerous. Greedy. Cheaters. Thieves. Breed like flies. Threaten community standards. Not like us. Don’t belong here. Such charges are routinely leveled at populations of animals (and plants) suddenly appearing far from where we expect to find them.
Social scientists have noted the similarities between such sentiments and our feelings about uninvited human immigrants. We dislike unlooked-for change then rationalize our feelings by telling stories that simplify and pigeonhole the problem. Everybody does it, even scientists. The fact that we scientists know more, about more cases, doesn’t translate to lesser alarm –– if anything, it intensifies our concern. Since most American ecologists were trained under the influence of Aldo Leopold, Rachel Carson and Jacques Cousteau, we grew up believing that any human influence on nature is negative. We even dismiss evidence to the contrary.
What does that have to do with lionfish? Well, nothing specifically, because until recently we knew very little about them. We had a sense of their distribution in the Indo-Pacific region. We learned to avoid touching them unnecessarily. We studied their venom. We call lionfish “pugnacious” and aquarists reported the animals are often hungry. Most field research on their ecology was done over the past decade, in the Bahamas. The justification for those studies was fear of unwanted change (a tried-and-true funding strategy). Biologists confirmed that lionfish are pugnacious and eat a lot. Furthermore, under experimental conditions, lionfish alter the local abundance of their preferred prey –– as any predator does. They’ve been spreading in a way that demonstrates how quickly regional currents disperse the larvae of even leisurely swimmers.
The past four centuries have seen impressive changes in the western Atlantic. Large predators were fished out, initiating “trophic cascades” that reconfigured food webs. Municipal, industrial and agricultural runoff initiated other systemic reorganizations. Trawling plowed the seafloor into the pelagic equivalent of an old field. Ghost nets fed scavengers and decomposers. New currents of commerce facilitated global exchanges of materials and biota. Scientists can infer and simply model what the seas were probably like once upon a time, but we can’t even support a decent nostalgia with real data.
What does that have to do with lionfish? Well, nothing specifically. Two species appear to be thriving in western Atlantic waters. By the basic criterion of persistence under prevailing conditions, they are ecologically fit. Where larger predators remain, they are eating lionfish, so the newcomers have entered the food web fore and aft. Over time, reproductive isolation and the influences of western Atlantic life may generate new species. Lionfish are fishable with spear or rod, reportedly tasty and interesting to watch. People can learn to handle lionfish safely. With all the crashing failures of ocean fisheries management, isn’t it curious that our first reaction to an accidental “success story” is to deplore it? Not really. We’re only human. To be human is to fear the darkness, including the metaphorical murk of unforeseen consequences and a world changing before our eyes.
Matt Chew is an ecologist and historian at Arizona State University’s Center for Biology & Society. He studies cultural components of ecological theories.