I remember my first lionfish sighting well. I was diving off of Fort Lauderdale, Florida for my PADI Advanced Open Water diver certification, and within minutes after descending to the bottom of our site, one of my buddies fanned out his hands on both sides of his head--a diving sign for "lionfish," which I didn't recognize at first--until I saw it in my field of view. The predator sat a few feet away from us, looking as confident as a king of the sea: and as one of few organisms at the top of the Atlantic Ocean food chain, it was just that.
The genus Pterosis, which contains two infamously invasive species, is the subject of today's blog. Pterosis includes Pterosis volitans, the Red Lionfish, and Pterosis miles, the Devil Firefish. These species are native to the South Pacific and Indian Oceans, a large area which spans areas such as Eastern Africa, the southern Middle East, Australia, India, China, Japan, and Korea. Now, they are found as far north as New York and as far south as southeastern Brazil. They are incredibly adaptable: to name just a few of their superpowers, they can eat just about anything for up to 30 times their stomach volume, and have been found floundering nearly 1,000 feet below the ocean's surface. Lionfish breed year-round and three to four times faster than most fish--females lay around 2 million eggs every year! Their rate of maturity after birth is a rapid 6 months, while newborn native reef fish take three to four years to become adults.
Different theories have been given as to how they spread: six lionfish were released into Florida waters when Hurricane Andrew hit a marine aquarium in 1985, and they also may have traveled in ship ballasts, devices that intake and output water to allow a ship to float at desired depths. Lionfish are a popular object of the aquarium trade, though they tend to be "thrown out," quite possibly directly into the ocean, when their owners find out the fish will eat any living thing sharing their tank. Scientists do know the invasive population started small, since their genetic makeup has shown to be fairly similar. The US Geological Survey (USGS) cautions that it may be difficult or impossible to tell either species apart, as their invasive versions have had a lot of room in the Atlantic to evolve new appearances.
Lionfish are making a large negative impact on their non-native environments. Unrecognized by native fishes as a dangerous hunter, hunting is made easy for them. The lionfish simply flare their fins like nets to corner fish and swallow their prey whole. Lionfish have even been known to hunt in groups that coordinate the trapping process to catch their prey. Because potential predators avoid lionfish for their frightening appearance and poison, lionfish are free to eat and multiply practically unchallenged; they present a major problem to Atlantic ocean ecosystems and their corresponding fishing industries.
The toxin these fish produce isn't just harmful to other fish--they can be deadly to humans. NOAA tells, "The spines of this species deliver a venomous sting that can last for days and cause extreme pain, sweating, respiratory distress, and even paralysis." Still, one of the best responses we can give to this invasive fish is human cooking! That's right; lionfish treated properly are edible--and even a potential delicacy! Cooking or removing the spines removes their poison, and the meat of the fish is not poisonous. Many dive shops in Florida host "Lionfish Derbies" and "Lionfish Removal Days" where they show the public how to catch, clean, and cook lionfish. Restaurants in areas where lionfish are invasive, as well as the grocery stores Whole Foods and Publix, have also jumped into the food trend. Researchers under institutions such as NOAA (the National Oceanic and Atmospheric Administration) and the University of Florida have also experimented with traps built specifically to capture lionfish. A lionfish-harvesting robot made its debut in 2017 through RSE (Robots in Service of the Environment), which was founded by the CEO of iRobot (known for its robotic, "ROOMBA" vacuums).
Sources:
Cover Photo Credit, National Park Service:
US Geological Survey:
National Geographic:
The National Oceanic and Atmospheric Administration (NOAA):
A scientific journal noting the current deepest lionfish sighting:
Smithsonian Magazine:
Robotic lionfish vacuum:
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