Ciguatera poisoning normally occurs in larger fish from warm tropical waters. The most popular types of these fish used for food include sea bass, grouper, and red snapper. In the United States, the waters around Florida and Hawaii are most likely to have contaminated fish. Worldwide, ciguatera fish poisoning is the most common type of poisoning from marine biotoxins. It is a major public health problem in the Caribbean.

The risk is greatest in the summer months, or any time a large number of algae are blooming in the ocean, such as during "red tide." A red tide occurs when there is a rapid increase in the amount of dinoflagellates in the water. However, thanks to modern transportation, anyone around the world may eat a fish from contaminated waters.

Scombroid poisoning most often occurs from large, dark meat fish such as tuna, mackerel, mahi mahi, and albacore. Because this poison develops after a fish is caught and dies, it does not matter where the fish is caught. The main factor is how long the fish sits out before being refrigerated or frozen.

Like ciguatera poisoning, most shellfish poisonings occur in warmer waters. However, poisonings have occurred as far north as Alaska and are common in New England. Most shellfish poisonings occur during the summer months. You may have heard the saying "Never eat seafood in months that do not have the letter R." This includes May through August. Shellfish poisoning occurs in seafood with two shells, such as clams, oysters, mussels, and sometimes scallops.

Always check with your local health department or fish and wildlife agency if you have any questions about the safety of eating any food product.