I floated above a rainbow-colored bommie in our anchorage off the Florida Keys, watching my husband stalk the reef below. Thunk. The muffled impact of his spear sent fish scattering in a dozen directions.
He kicked to the surface with his prey: a zebra-striped lionfish. “Fish tacos for lunch, anyone?” Our kids cheered from the dinghy. I grinned, then dove down with my own spear to collect another one for the grill.
Lionfish are delicious. Plus, hunting them helps restore coral reefs. These Indo-Pacific-based predators are invasive in the Caribbean and the Gulf of Mexico. Left unchecked, they quickly decimate populations of native Atlantic reef fish.
But the best part of eating lionfish for lunch? My family doesn’t have to worry about coming down with ciguatera poisoning.
Like many sailors, we believe that eating fresh seafood is a fabulous fringe benefit of cruising. We pride ourselves on harvesting dinner by trolling between islands or snorkeling at anchor. When our luck runs short, we often buy fish from locals or order it at beachside restaurants.
I never used to worry about getting sick from our tasty seafood meals. Until we met a fellow sailor who shared the terrifying details of his debilitating brush with ciguatera after eating a grouper he caught in French Polynesia: violent vomiting and diarrhea, painful muscle aches, difficulty breathing, drooling, numbness in his fingers, toes, and mouth.
Suddenly, eating the fish we caught while sailing felt a little too much like playing Russian roulette.
Ciguatera is the most common nonbacterial seafood poisoning, afflicting up to 500,000 people per year around the world. It’s caused by microalgae that bloom near coral reefs in tropical and subtropical waters. This neurotoxin bioaccumulates in the food web, which means it increases in concentration as reef-grazing fish eat the ciguatoxic algae, and then predatory fish eat those fish, and bigger fish eat those fish.
Humans get sick when we eat fish with high enough concentrations of the toxin. Ciguatera poisoning can leave its victims with bizarre lasting affects, like the reversal of hot and cold sensations (your scalding coffee might taste like it’s iced), facial paralysis, the feeling that your teeth are falling out, or nightmares. These symptoms can be re-triggered for years after the initial onset by eating certain foods or drinking alcohol.
Ready for ciguatera to get even more creepy? You can’t see, taste, or smell the toxin, nor is it eliminated by cooking, cleaning, or freezing fish. Plus, it has no known antidote.
To preserve our beloved fish taco tradition aboard, I delved into guidelines on how to avoid ciguatera. As with mercury contamination or other environmental toxins that bioaccumulate, research shows that it’s best to avoid large predatory fish that weigh over 10 pounds. Species considered high risk for ciguatera include barracuda, red snapper, grouper, amberjack, and sea bass. However, in some hotspots even smaller fish had high concentrations of ciguatera. The toxin has also been found in some non-fish seafood like squid or lobster.
As for the lionfish we grilled for our tacos, research shows they are a fairly safe bet. Scientists tested lionfish from 74 locations and found that less than 1% contained high levels of ciguatera. (Side note: Lionfish do have venemous spines on their pectoral fins, so be careful when handling them. We use scissors to cut off the spines while the fish are still impaled on our spear.)
Scientists are hard at work on treatments for ciguatera poisoning, such as some way to deactivate the neurotoxin once it’s ingested. Researchers from Florida Gulf Coast University and other institutions are also working on rapid-screening methods to test fish for algae-related toxins, as well as ways to predict algal blooms to warn people when and where toxic outbreaks occur.
Meanwhile, choose your seafood and your fishing spots cautiously when harvesting meals while sailing. It’s a good idea to ask the locals if anyone has experienced ciguatera poisoning in the area recently. You can also hail fishermen to vet whether it’s safe to eat the local fish, and ask if they avoid harvesting from any of the nearby reefs.
And don’t be afraid to spread the word among your sailing friends that the biggest fish on the reef aren’t the best to eat. Flaunt the fact that you’re going after the smaller ones to steer clear of ciguatera poisoning.
January/February 2025
