(CNN) -- Four years ago, lobster fisherman Gary Nichols had never laid eyes on a lionfish, but today his traps are full of them.
"You'll get two or three decent traps with lobster, but if you get four or five lionfish, the lobster don't like it," Nichols said.
He says he catches so many lionfish now (up to 200 pounds every day) that he's started to sell them. But where his lobsters sell for $16 per kilogram, lionfish only make him $12.
Lionfish are causing a huge strain on his business and the wider commercial fishing industry in Florida, devouring other fish populations -- in some cases reducing them by up to 90%.
According to the Florida's Department for Environmental Protection, lionfish are native to the Indian and Pacific Oceans, but were accidentally introduced into Atlantic and Caribbean waters during the 1990s.
With no natural predators in the Atlantic and an ability to reproduce year-round, their numbers have risen unabated in recent years.
Not only are lionfish causing grief for lobster fishermen like Nichols, they are also threatening to upset the balance of the fragile reef ecosystem.
"What we've found through stomach analysis and working with fish that have been collected is that they are consuming a wide variety of prey," said Lad Akins, director of special projects for REEF, a marine conservation group.
"They are eating almost anything that fits in their mouth. The lionfish can probably consume in excess of half of its own body size. They can take quite large prey," he added.
Some of what they eat are commercially valuable species, says Akins, like juvenile grouper and snapper that the fishermen depend on.
Ecologically important species like mudfish which graze on algae, stopping it growing over the reefs, are also being impacted, he says.
"I'm an optimist but potential impacts of lionfish could result in major shifts in the ecology of our Caribbean and West Atlantic reef barriers," Akins said.
"It could result in the extinction of some fish species."
In an effort to minimize their impact, REEF run a monthly contest, open to both businesses and individuals, awarding prizes to those who catch the most lionfish. It also run workshops educating divers about safe collection and removal techniques.
The U.S.'s National Oceanic and Atmospheric Administration has also joined the fight with a campaign that encourages people to eat lionfish.
Its "If we can't beat them, let's eat them!" slogan has been taken up by restaurants like the Fish House Encore in Key Largo.
General manager Michelle Kosiek has been serving lionfish for the past 18 months.
"We're putting it on the menu to try to get them off the reef and try to get people to actually like them and enjoy them," Kosiek said.
"There is a little bit of fear factor eating them. But once they know that the flesh has no poison, they're ok with it and want to try it."
By encouraging more people to eat lionfish, Kosiek hopes to entice fishermen to get them out of the ocean.
Once cooked, the venomous spines are harmless and Peter Tselikis, chef at Field House Encore, says the response from customers has been very encouraging.
"In the beginning it was sort of more like a novelty. But those who tried it have spoken well of it," Tselikis said.
Nichols, who has spent over a quarter of a century fishing the waters off Florida, remains philosophical about the threat, speculating it could be cyclical and that nature usually finds a way to adapt.
"Maybe it's just taking its time," he said.
"But it's really strange. I mean, having fished all my life, it's just hard to believe that in a short space of time something like this can happen."