Invasive species represent the second most significant cause of species extinction worldwide after habitat destruction, and in islands, they are undisputedly first. The impacts of alien invasive species are immense, insidious, and usually irreversible - IUCN
By Katie Pyzyk, National Geographic
PUBLISHED July 23, 2015
CONCH KEY, Florida—Fisherman Gary Nichols, who has been finding lionfish in his lobster traps off the Florida Keys for years, has noticed something different this year: Lionfish are eating each other.
“When you bring them up from those depths, lionfish spit out what’s in their stomachs, and I noticed quite a few of them regurgitating other lionfish. I didn’t even have to gut them to see it because they’re still in their mouths,” Nichols says. “They’re pretty incredible eaters so I’m not really surprised.”
Cannibalism may seem like nature’s way of coping with Florida’s growing lionfish invasion, but it is unlikely to offer a cure.
Visually stunning with their maroon and white stripes and long, fanlike fins, lionfish are considered the most destructive exotic species in marine waters off Florida and the Caribbean. They have voracious appetites and consume dozens of organisms in one feeding, drastically reducing other fish populations and altering delicate reef ecosystems.
In addition, lionfish can lay up to 30,000 eggs every four days, and their venomous spines leave them with no known predators in Florida waters.
DNA evidence has confirmed that lionfish in Caribbean waters are engaging in cannibalism, and researchers are trying to determine if it's because the fish is depleting its existing foods, such as gobies and snapper.
Cannibalism Is Rare
Off the Florida Keys, Nichols used to find shrimp and other small invertebrates in his lobster traps, but he has noticed a steep decline. He suspects that lionfish are eating the crustaceans, and because that can’t satisfy them, they are resorting to preying on each other.
Picture of a lionfish in the Red Sea
"I've seen a lot bigger lionfish [this year] and I'm seeing lionfish full of lionfish," he says. "They're eating all the little stuff up. I think because they've eaten up most of their food sources... now they're eating other lionfish."
Cannibalism does occur in some species of reef fish, but it is rare, according to marine scientists. A study of stomach contents discovered cannibalism in four of 130 lionfish collected in the Bahamas, with similar results from a study of 157 in Mexico.
Due to a lack of research, it's unclear if lionfish cannibalism is holding steady or increasing.
"If we saw an increase in cannibalism that could mean that there are so many lionfish that lionfish are controlling themselves, but I don't think it's reached that point yet," says Nova Southeastern University marine researcher Matthew Johnston, who tracks lionfish population trends. "It would be interesting to see over time if there's an increase, because I would think that would mean that they're getting close to their carrying capacity for that particular area."
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Established in 1999, the Guy Harvey Research Institute (GHRI) is a collaboration between the renowned marine artist, scientist and explorer, Dr. Guy Harvey, and Nova Southeastern University's Oceanographic Center. The mission of the GHRI is to provide the scientific information necessary to understand, conserve, and effectively manage the world's marine fishes and their ecosystems. The GHRI is one of only a handful of private organizations dedicated exclusively to the science-based conservation of marine fish populations and biodiversity. The research, education and outreach activities of the GHRI are supported by the Guy Harvey Ocean Foundation, AFTCO Inc., extramural research grants, philanthropic donations by private businesses and individuals, and NSU. Track the sharks tagged by the GHRI with our web app.
Lionfish populations have expanded throughout the Atlantic, Caribbean and Gulf of Mexico and threaten native reef ecosystems. The introduction of an exotic species with no natural predators threatens to destabilize the delicate natural balance of our local waters. OceanGate's professional crew, supplemented by leading researchers and select expedition participants, will execute at least four dives over two days utilizing a high power fish collection system to capture lionfish.
Global Invertebrate Genomics Alliance - Describing the wide functional and structural diversity of invertebrates requires an integrated approach that includes not only traditional biological sciences (e.g., anatomy, ecology, behavior, physiology, paleontology), but the burgeoning interdisciplinary efforts of genomics. Following on the success of the human genome project and the current progress of the vertebrate Genome 10K project (Genome 10K Community of Scientists, 2009), GIGA proposes to assemble or assist in the coordination and collection of samples spanning the broad spectrum of (non-insect/ non-nematode) invertebrate phylogenetic diversity suitable for whole-genome sequencing.