Beware the lionfish – UVI study finds ciguatera

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A newly published study by researchers at the University of the Virgin Islands finds that the lionfish that live in territorial waters can contain the ciguatera toxin that causes fish poisoning, Aldeth Lewin reports for The Virgin Islands Daily News.

Lionfish are an invasive species from the Pacific that have no natural predators in the Caribbean Sea and Atlantic Ocean. They are voracious eaters and consume high numbers of reef fish.

The exploding population of lionfish in the region has led to a local campaign to kill as many lionfish as possible to protect the reefs.

As part of that campaign, many people have begun to eat lionfish, and it is even served on the menus in some local restaurants.

“While this could represent a great economic opportunity in local communities as an artisanal fishery, lionfish also pose a potential human health hazard as a vector for ciguatera fish poisoning in endemic regions such as the U.S. Virgin Islands,” Bernard Castillo, UVI assistant professor of chemistry, said in a written statement. “Ciguatera fish poisoning is a leading cause of seafood-borne illness and is estimated to cause up to 500,000 illnesses annually.”

As part of the study, published in Marine Drugs Journal, researchers collected more than 180 lionfish from waters surrounding the territory throughout 2010 and 2011 and tested them for levels of ciguatoxins.

Ciguatera poisoning is caused by naturally occurring toxins, called ciguatoxins, that are produced by microscopic plants – gambierdiscus toxicus – that live on seaweed and other surfaces within coral reef communities. When fish eat seaweed or algae, they also consume the organisms and the ciguatoxins build up in the fish’s flesh.

The toxin is fat soluble – it is stored in the fish’s body and not excreted – so it builds up as it goes up the food chain. The bigger fish eat the little fish, and the toxin gets passed on until it is consumed by humans.

Predators at the top of the food chain – such as barracuda – can end up with large amounts of the toxin in their flesh. No test can be done to determine whether a fish is poisoned, and cooking, freezing and preparation methods have no affect on the toxin. The toxin is flavorless and odorless as well.

Fish most commonly implicated in ciguatera fish poisoning include grouper, barracuda, snapper, jack and mackerel, according to UVI researchers.

Now lionfish can be added to that list.

“We definitely suspected based on where they are in the food chain that they should have it,” UVI associate research professor of marine science Tyler Smith said.

The study found:

– Lionfish can contain ciguatoxins at concentrations exceeding U.S. Food and Drug Administration guidance levels for safe seafood.

– Lionfish have 12 percent higher ciguatoxins than the FDA guidelines and levels are similar to other predatory fishes, such as the schoolmaster snapper.

– Lionfish consumption has risks and should be treated similarly to other small predatory fishes. It should not be consumed from areas known to produce toxic fish.

– Lionfish control strategies, including marketing and eating fish, should continue in the territory, but it is best to consult an experienced commercial fisherman on which fish are likely to be less of a risk.

“I’ve never heard of anyone getting ciguatera from lionfish,” Smith said.

However, after collecting samples from across the territory and performing the analysis in the lab, it is possible to get the poisoning from eating a lionfish the same way it is possible to get fish poisoning from eating a number of locally caught fish.

“So, it’s the same kind of precautions,” he said.

Lionfish samples were taken from the north shelf, the south shelf and a few areas on St. Croix. Most of the samples came from the south shelf, which is an area that local fishermen have avoided for years in hopes of avoiding toxic fish, Smith said.

While the study did not look at where the ciguatera was found geographically, future studies may help narrow that down, according to Smith.

“We still need to finish the work on lionfish to see if that pattern holds, but I suspect that it does,” he said.

Smith said he does not believe that the study’s findings should deter people from eating lionfish as long as it is caught by a knowledgeable commercial fisherman.

“The good news from the study is that it suggests that you can eat lionfish and have a low risk of fish poisoning if they are taken from trusted sources,” Smith said. “From an ecological standpoint, eating lionfish is a good thing. You are culling them from the reef. It’s a good way of controlling them, and they can fetch a fairly high price on the market.”

Bryan Lewis, the chef and owner of Twisted Cork on St. Thomas, has had lionfish tacos on the menu regularly and said no one has ever reported getting fish poisoning from them.

“We’ve never had an issue,” Lewis said.

He said he trusts his supplier – who does catch the lionfish locally – and he will continue to serve it in his restaurant.

For the original report go to http://virginislandsdailynews.com/news/beware-the-lionfish-uvi-study-finds-ciguatera-1.1867414

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