“We’re going to win this one,” said Doug, an instructor at the Islamorada Dive Center, as he peered into the cooler. “I have a good feeling.”

It was a balmy February afternoon in the Florida Keys and excitement was high. Since dawn, teams of divers had been scouring reefs with one target in mind—lionfish—but this is not your average fishing tournament.

The Facts

Originally from the Indo-Pacific, lionfish are one of the most destructive invasive species in the Western Hemisphere (mark National Invasive Species Awareness Week). As voracious predators and prolific breeders (one female can produce over two million eggs per year), lionfish are wreaking havoc throughout the Western Atlantic, Caribbean, and Gulf of Mexico.

Fortunately, ocean lovers are fighting back.

This time every year, the Reef Environmental Education Foundation hosts the Winter Lionfish Derby, an all-day event where teams use spears and nets to collect as many lionfish as possible and compete for a slew of prizes. Since 2009, more than 14,830 lionfish have been removed as a result of REEF Derbies, and it’s making a difference—studies in the Bahamas suggest that derbies can reduce local lionfish populations by about 75 percent.

The Frenzy

The year I attended, by 5pm the scoring tents were a flurry of activity as teams hauled in coolers of lionfish. Elizabeth Underwood, REEF’s Lionfish Coordinator, carefully measured each fish, calling out numbers to an intern who furiously jotted them on a clipboard. Measured fish were then sent down an assembly line, where researchers removed DNA samples for various projects, all with the similar goal of learning more about the impacts of the invasive predator.

Next to them, REEF volunteers armed with filleting knives sliced up the carcasses, carefully avoiding the fish’s venomous spines which can inflict nasty stings that cause pain and swelling. The white fillets were then pushed to the end of the table, where they were diced and added to a large bowl of onions, peppers, and lime juice to make lionfish ceviche, based on the recipe in The Lionfish Cookbook.

The Food

Soon, curious observers from the tiki bar next door strolled by to investigate. “Marcy, come look at this! This is that fancy fish thing our guide was telling us about,” a slim British woman called to her friend. They peppered Elizabeth with questions about lionfish, wondering where they came from, why they’re harmful, and more. Elizabeth answered with the enthusiasm and clarity of a seasoned educator, addressing each of their questions in turn. Visitors sampled little paper cups of ceviche and snapped iPhone pictures of the gaping fish lying on ice in large coolers. Meanwhile, derby participants shared stories from the day over some cold beers.

By 6pm, the results were in. The participating teams had collected 99 lionfish total, with Islamorada Dive Centerwinning first place with a lion’s-share 86 fish. Had those 99 lionfish not been removed, they would have consumed an estimated 198,000-380,000 native prey fish throughout the Florida Keys.

“Thank you all for participating today!” Elizabeth said to the enthusiastic crowd.

“Remember, every lionfish counts.”