Can eating barracuda make me sick?

The great barracuda, with its powerful jaws, is more terrifying to some than even sharks. Discover more about this and other mysterious marine creatures through captivating pictures. ©­iStockphoto/RWBrooks

If you're craving oysters, seafood enthusiasts suggest checking the calendar before diving into a dozen on the half shell. The rule of thumb for oysters is to only indulge in them during months that end in "r." When attending a crawfish boil, only pick up mudbugs with curled tails—straight tails indicate they were dead before they hit the pot, resulting in less flavor. And when preparing a fish fillet at home, ensure it has a fresh smell (but not a fishy one), bulging eyes (but not unsettling), and glistening skin (not slimy).

The world of seafood dining comes with a myriad of rules to avoid foodborne illness. The Centers for Disease Control and Prevention (CDC) warns that raw animal meats, including shellfish, are most prone to contamination. Shellfish, in particular, are filter feeders and may carry harmful microbes [source: CDC]. According to the U.S. Food and Drug Administration (FDA), all seafood can harbor dangerous bacteria and viruses, such as salmonella, worms, hepatitis A, and the Norwalk virus. For this reason, the FDA advises that all seafood be cooked or frozen thoroughly before consumption.

However, even cooked fish—whether grilled, fried, boiled, or charred—can still pose a risk. Sometimes, fish may contain bacteria that neither heat nor freezing can eliminate. One such toxin has occasionally been found in barracuda meat.

Barracudas are infamous in the underwater world for their menacing reputation. More feared by some swimmers and scuba divers than sharks

, these fish can swim with incredible speed and strike with force. Unlike sharks that hunt using scent, barracudas rely on their bulging eyes to spot prey, making it easier for them to target swimmers' dangling legs. Their fierce underbite showcases two sets of menacing teeth. Barracudas vary in size from 18 inches (45 centimeters) to 6 feet (1.8 meters) and are found in warm, tropical waters near reefs and shorelines.

The great barracuda, distinguishable by black spots on its abdomen, is the largest species, growing to over 100 pounds (45 kilograms) at maturity. Due to its size, it’s a popular target for sport fishermen seeking a challenging fight. However, those aiming for a meal might avoid the great barracuda, as its meat can cause severe stomach issues.

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Barracuda Gone Bad: Ciguatera Fish Poisoning

Barracudas can carry ciguatoxin, a harmful toxin. ©iStockphoto/THEPALMER

The Centers for Disease Control and Prevention (CDC) ranks barracudas as one of the top predatory fish that consumers should avoid. This is because large, predatory fish like barracudas, which inhabit reef areas, have a higher risk of carrying ciguatera fish poisoning. As the name suggests, this illness is caused by a toxin called ciguatoxin. While ciguatera fish poisoning can cause a range of uncomfortable symptoms, it is rarely fatal.

Ciguatoxin is produced by certain types of algae that thrive in deep tropical waters. More specifically, it originates from a single-celled organism called dinoflagellate, which grows on various algae species. Since barracudas are carnivores, they do not ingest the algae directly. Instead, they consume smaller fish like tuna, herring, and anchovies that have fed on the algae, which then transfers the ciguatera toxin into the barracuda’s system. As the barracuda digests these fish, the toxin accumulates in its flesh, fat, and organs [source: Hoffman et al].

The ciguatoxin doesn’t harm the barracuda itself, but almost everyone who eats the contaminated fish will experience unpleasant symptoms. Within 24 hours, the poisoning triggers intense nausea and vomiting, which can last for several days. A tingling sensation in the nerves, or paresthesia, may persist even longer. Other symptoms include headaches, a metallic taste, and the sensation of loose teeth. In rare cases, ciguatera fish poisoning can lead to lasting nerve and heart damage.

The incidence of ciguatera fish poisoning is relatively low, occurring in approximately 5 to 70 cases per 10,000 people annually [source: Louisiana Department of Health and Hospitals]. One such incident in 1997 involved 17 crew members on a ship off the Texas coast, who fell ill after eating barracuda [source: CDC].

Other large, predatory fish in the same regions as barracudas can also carry ciguatera. Over 500 species of fish fit this description, including mackerel, amberjack, and grouper [source: Hoffman et al]. To reduce the risk of ciguatera when consuming predatory tropical fish, consider which part of the fish you're eating. The toxicity of fish parts, ranked from most to least toxic, is as follows: liver, intestines, testes, ovaries, and flesh [source: Bannerot].

Since there's no reliable way to determine if a barracuda is infected with ciguatera, there’s a small risk of illness from eating it. If you choose to go ahead, avoid the head and internal organs, and opt for a smaller fish. The bigger the barracuda, the more fish it has eaten. If that still seems too risky, play it safe and stick with the classic fish and chips.