The U. S. Food and Drug Administration issued a warning this week to seafood processors regarding toxic fish in the Gulf of Mexico, after several outbreaks of ciguatera fish poisoning were confirmed.

The letter from the FDA was sent Tuesday and warns seafood processors that fish such as grouper, snapper, amberjack and barracuda feed on fish that have eaten toxin marine algae, which makes them a threat to consumers, the Associated Press reported.

The toxic fish were all harvested in the Northern Gulf of Mexico, near the Flower Garden Banks National Marine Sanctuary, the FDA said, near the coast of Texas and Louisiana.

Symptoms of ciguatera poisoning include nausea, vomiting, vertigo and joint pain; the illness can be debilitating, as neurological symptoms can last for months or even years, the AP informs.

The first case of ciguatera fish poisoning was reported in late November, with almost 30 cases reported across the country to date, the FDA said. Outbreaks of the illness were confirmed in Washington, D.C., and St. Louis.

Under current regulations, fish processors are recommended to not purchase fish harvested near the sanctuary and to put in place plans to control food safety hazards.

Ciguatera is rare for fish in this area, at is more commonly found in fish living in tropical and subtropical regions, including the Caribbean Sea, the South Pacific Ocean and the Indian Ocean.

The FDA now considers ciguatera fish poisoning a food safety hazard, likely to occur in grouper, snapper, and hogfish captured within 10 miles of the marine sanctuary and amberjack, barracuda and other wide-ranging species captured within 50 miles of the sanctuary.

Those concerned that they may have ciguatera poisoning are advised to report their symptoms as well as the type of fish they consumed to a doctor or local health department.

For more information on ciguatera fish poisoning, visit the CDC’s webpage on the subject, at www.cdc.gov.