A red lionfish patrols its favored habitat – a natural reef.
Like many invasive species, the red lionfish is nice to look at, reproduces prolifically, has few natural predators and preys on native species.
A few examples of similar invasive marine activity are witnessed in the Cuban tree frog, Asian swamp eel, and suckermouth catfish. These aquatic animals were introduced to Florida either intentionally or by accident, and have since established themselves by displacing native species.
As for the lionfish, its voracious, carnivorous appetite includes a menu of more than 70 species of fish, some with great economic and recreational importance.
The red lionfish (Pterois volitans) is a beautiful fish. It has greatly elongated dorsal-fin spines, and the membranes of the fins are often spotted. The body is white or cream colored, with red to reddish-brown vertical stripes.
The vertical stripes alternate from wide to very thin (with the thin stripes being more numerous) and sometimes merge along the flank to form a V-shape. They generally grow to about 15 inches, with some adults as large as 18.5 inches. Two types inhabit Florida waters, the red lionfish and the devil firefish. Almost 90 percent are red lionfish, commonly called lionfish.
The lionfish, while beautiful, is also very destructive. A native to the Indo-Pacific, the spiny, ornate fish – once only found in Florida in expensive aquariums – began to turn up in small numbers in the mid-1980s along the Atlantic seaboard. A member of the scorpionfish family, their numbers exploded in the last decade, and these fish can now be found in the Gulf of Mexico.
No hard numbers are available yet for Tampa Bay, but scientists confirmed that they are definitely there, and in rapidly growing numbers. Fishery experts said that without an effective containment program, the lionfish would rapidly expand its presence in the Gulf of Mexico.
Recent evidence suggests that this species also can invade estuarine systems, threatening important nursery communities. Lionfish have been reported in fairly large numbers in the Loxahatchee and Indian Rivers, indicating that they are able to move into brackish water.
Their reproductive biology, their aggressive predatory behavior on a variety of fish, and ability to exploit a wide range of habitats has allowed the red lionfish to expand throughout the western Atlantic and Caribbean rapidly and in high densities.
These fish pose a significant threat to valuable native species such as grouper, snapper and sea bass. Lionfish are voracious predators and not only eat these fish, but over-compete with them for available food resources. Although they are gape-limited predators, they have been noted to eat fish two-thirds their size. They also play a big part in the destruction of important reef habitat.
One of the lionfish’s favorite meals is the parrotfish, which eats toxic algae that grows on reef fauna, thereby keeping the reef healthy. There is also evidence that the lionfish affect the spiny lobster fishery. There are concerns that invasive lionfish could affect the profitability of the spiny lobster industry, but ecological interactions between the two species are not well understood. An inverse relationship has been observed in tests that show Spiny lobster populations decline in the presence of embedded adult lionfish. In the Florida Keys, lobster fishermen found that lionfish are the leading by-catch species and have reduced lobster harvest by as much as 50 percent.
According to experts such as R. LeRoy Creswell with the University of Florida’s Sea Grant Program, the lionfish, if left alone, will eliminate up to 80 percent of reef fish from a given area.
“The lionfish is the 800-pound gorilla in our waters,” said Creswell. “I’ve been in this field for 30 years, and this is the most important issue for fisheries that I have dealt with. This is a very destructive marine animal.”
The red lionfish is extremely efficient when it comes to reproduction, and has a unique way of spawning. Females release two gelatinous egg masses of about 12,000 to 15,000 eggs each. These masses float and can drift for about 25 days. Lionfish can spawn every four days in warmer climates such as the Gulf of Mexico, hence the anxiety about its proliferation. Studies from Pensacola showed the lionfish population has doubled annually since 2010. Lionfish rodeos, in which spearfishers collect lionfish, have resulted in up to 1,400 lionfish being harvested in a day, but a single lionfish can produce as many as 200,000 eggs per month, easily replenishing the population’s numbers.
It is also dangerous to deal with due to its poisonous venom. Lionfish have 18 venomous spines that are used defensively against predators and humans. These spines should be avoided during capture and handling because of their ability to cause painful injuries. Thirteen long venomous spines are located along the front of the dorsal fin, which is located on the top of the fish. Two short venomous spines are located on the pelvic fins (one on each side), which is located on the bottom of the fish closest to the fish’s head. Three additional venomous spines are located along the front edge of the anal fin, which is located on the bottom of the fish nearest the tail. The large and featherlike pectoral fins and the tail fin do not contain venomous spines. Although its spines are poisonous, its flesh is not and is reportedly an excellent tasting fish.
What to do about it
Efforts are underway in certain regions of Florida to reduce the lionfish population through “lionfish rodeos” in which spearfishers dive and spear the animals in their habitat, which is often in natural or artificial reef crevices, and around any underwater wrecks or oil wells. This is currently the most effective method to catch lionfish because they are good at evading traps and not easily caught with rod-and-reel, although sometimes a fisherman gets lucky. Recently, a deep-water trip by Hubbard’s Marina ended up with a record-setting lionfish catch. At 16 inches, it is the largest Lionfish caught by rod-and-reel, and the record for spearfishing is only a half-inch larger.
In Florida, lionfish rodeos sponsored by the Emerald Coast Reef Association occur frequently in Okaloosa County. Also, the Escambia County Marine Resources hosted a pilot event this summer, and will begin a full lionfish control program in 2014. Although the lionfish rodeos are effective to some degree, more effective methods are required to keep the lionfish in check.
UF’s Creswell said there is a need for a deepwater trap that is designed specifically for lionfish and does not induce much by-catch.
“Spearfishers can only go so deep, and many lionfish live at depths deeper than divers can go,” said Creswell. “We need to get creative and try things such as luminescent lights or specific acoustic noises to draw lionfish into the traps but not catch grouper and other valuable fish.”
Creswell noted that we will likely never eradicate the lionfish from local waters, but that we must keep the population in check and get better numbers on populations.
“Until we come up with a better solution, it is crucial that spearfishing rodeos are sponsored and are successful in areas with dense lionfish populations,” said Creswell. “When done right, these rodeos are proficient at removing many lionfish, but we need ancillary solutions to help the effort of the spearfishers.”
Meeting of the minds
This past October, the Florida Fish and Wildlife Conservation Commission held the first Florida State lionfish summit in Cocoa Beach. Researchers, fishery managers, divers, fishermen, and the general public received research updates, discussed current issues, and provided input regarding future management needs.
Many issues were discussed and numerous biologists and fishery managers presented information. One of the puzzles is exactly how the red lionfish was introduced to Florida waters. Several theories were suggested, but research indicates that a single introduction of red lionfish in Florida initiated the invasion into the Western Atlantic, presumably from just a few aquarium specimens.
In the U.S., lionfish have rapidly increased in abundance and are now as abundant as many native grouper species in the Atlantic Ocean. Surprisingly, although it was thought the species’ northward expansion along the Atlantic coast of the U.S. would be limited by cool water temperatures, lionfish have been observed in water as cold as 56 degrees off the southern coast of Long Island. At the meeting, researchers from the University of Florida said that although invasive lionfish may never be eradicated from Florida’s coastal waters, it is possible to keep them under control in specific, targeted areas using plenty of manpower
Another major issue is that 60,000 lionfish continue to be imported into the state each year, although the state legislature is poised to implement laws prohibiting their importation.
Laws being proposed
The Florida Legislature is taking action to help reduce lionfish populations. Two bills filed – one in the House and a companion bill in the Senate – if passed by the end of legislative session on May 2, would put an end to the public’s ability to buy lionfish for the centerpieces of their aquariums. Raising them for sale would become a level two felony.
“What the bill is going to do is prohibit the importation and sale of them,” said Sen. Greg Evers, R-Baker, who introduced the Senate version of the bill. “All of the details of the bill have not been decided. I’m saying let’s get rid of them. Put an end to lionfish in aquariums.”
Even though there is no current aquaculture industry for lionfish in Florida, the bill would prohibit raising them, according to the Florida Department of Agriculture and Consumer Services. The proposed bill also addresses importation of lionfish hybrids and eggs, and calls for allowing the Florida Fish and Wildlife Conservation Commission to write and enforce the rules for the law should it pass. Evers said the bills are small measures that could help control the proliferation of lionfish in Florida waters.
They must be controlled
A team from the University of Florida spent much of 2011 working with the Central Caribbean Marine Institute, and with local dive masters and scuba volunteers who removed lionfish weekly from several sites off Little Cayman Island, in the Caribbean Sea. The team asked the divers not to remove lionfish from an area called Rock Bottom Wall, so it could be used as a control site.
At the lionfish removal sites, their density decreased over time, and the size of the fish that remained were smaller on average. In comparison, lionfish numbers increased markedly at the control site. The researchers used mathematical modeling programs to show that 35 to 65 percent of the lionfish would have to be taken from an area every year to keep the lionfish numbers in check. And even if large numbers of lionfish are harvested, that’s not likely to happen, said Mike Allen, a UF professor of fisheries ecology and one of the study’s authors.
But those efforts will have to be sustained. The conclusion by scientists was that the lionfish must be pursued hard and over a long period of time.
The appearance of lionfish recently near the Big Bend area of Florida has scientists concerned, he said, because that area’s large seagrass beds provide critical nursery-ground area for gag grouper, an important sport and food fish.
An excellent meal
According to many folks who have eaten red lionfish filets, the report is that it is a “delicate-flavored and light-tasting fish.” No bag limits exist for lionfish, so if you’re a go-getter, you can spear or net a large number and sell them to a local fish shop, once you’ve filleted them. Or make a different Thanksgiving dinner.
It’s doubtful the fish shop wants to filet them due to poisonous barbs on the top and bottom of the fish.
However, its flesh is non-poisonous and is edible. If you can catch them and would like to consume lionfish, you should view this excellent video on “How to Filet a Lionfish.”
If you do catch a lionfish, officials say to send a tissue sample to the Lionfish Tissue Repository (LTR). Contact Dr. James Morris at James.Morris@noaa.gov and he will reply with detailed instructions.The LTR is a multi-national collaborative program intended to maintain and provide tissue samples for research into the ecological and evolutionary processes driving the ongoing invasion of lionfish.
The LTR is currently only collecting dried fin clips (easy to mail) and heads (that include otoliths, or ear bones, useful for aging fish).
For details on tissue sampling methods and submission, contact Morris.