• Tropical locations: Florida, Hawaii, U.S. Virgin Islands, Puerto Rico
• Affected are reef fish and those who eat them (e.g., barracuda, snapper, amberjack, grouper, kingfish)
• Humans may experience vomiting, cramps, diarrhea, headache, weakness, numbness, etc.
• Ciguatoxin and maitotoxin molecules alter the passage of sodium and calcium ions, respectively

• Caused by dinoflagellates found on our northeastern and western coasts; no reports of DSP in the U.S.
• Mussels, oysters, scallops, and the humans who eat them are affected
• Toxin molecules affect proteins that control the sodium secretion by intestinal cells, causing nausea, vomiting, abdominal pain, and diarrhea in humans; exposure to DSP toxins has been suggested to promote the formaton of digestive tract tumors

• Gulf of Mexico coast, Florida, North Carolina, South Carolina
• Manatees, bottlenose dolphins, oysters, fish, clams, and birds are affected
• Humans may be affected by breathing seafoam or eating contaminated shellfish
• Toxin molecule induces a greater flux of sodium ions causing diarrhea, vomiting, tingling in lips/tongue/throat, dizziness, etc.; asthma-like symptoms can result from airborne toxins

• Widespread in U.S.: Alaska, west coast, Maine to New York
• Mussels, clams, crabs, oysters, scallops, herring, sardines, marine mammals, birds are affected
• Humans may be affected by eating contaminated shellfish
• Toxin molecule inhibits the passage of sodium ions causing numbness, paralysis, respiratory failure, death

• Widespread in U.S.: Alaska, west coast, Gulf of Mexico, Gulf of Maine
• Razor clams, dungeness crabs, scallops, mussels, anchovies, sea lions, brown pelicans, and cormorants are affected
• Humans may be affected by eating contaminated shellfish; toxin molecule attacks human central nervous system causing vomiting, abdominal cramps, diarrhea, short-term memory loss, etc.