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Red Marine Algae Diseases

According to Monica Bruckner from Montana State University, a red tide is a harmful algal bloom (HAB) that takes place when red algae become so numerous that they discolor coastal waters. HABs deplete oxygen and release toxins that can cause illness or death in animals and humans. Fish eat the algae but are unaffected by the toxins. The toxins accumulate and become concentrated to poisonous levels for the mammals and humans that eat the tainted fish. There are several diseases attributed to HAB toxins.

  1. Ciguatera Fish Poisoning

    • Ciguatera fish poisoning (CFP) is an illness caused by eating fish that have eaten toxins found in HABs. Ciguatera causes nausea, vomiting, and neurological symptoms such as tingling in fingers and toes. An infected person may also find that hot feels cold and cold feels hot. The symptoms caused by CFP generally disappear within a few weeks but may last for several years.

    Paralytic Shellfish Poisoning

    • Paralytic Shellfish Poisoning (PSP) is common along the coasts of the U.S. and Canada. PSP, caused by saxitoxin, occurs in humans who ingest shellfish that have ingested toxic red algae. PSP disrupts nerve function, causing tingling, numbness and paralysis. In extreme cases, death can result from respiratory paralysis.

    Diarrhetic Shellfish Poisoning

    • Diarrhetic Shellfish Poisoning (DSP) commonly occurs in people living in Japan and Europe, though cases have been reported in several other countries. DSP, caused by okadaic acid, is obtained through the ingestion of shellfish that have eaten toxic red algae. DSP causes diarrhea, nausea, vomiting, abdominal pain and cramping, but is rarely lethal.

    Amnesic Shellfish Poisoning

    • Amnesic Shellfish Poisoning (ASP) has been recorded in people along the eastern coast of Canada. ASP is caused by domoic acid found in soft-shell clams and blue mussels that have ingested certain kinds of algae. ASP causes gastric and neurological symptoms such as dizziness, disorientation and memory loss.

    Neurologic Shellfish Poisoning

    • Neurologic shellfish poisoning (NSP) in humans is caused by brevetoxins. Brevetoxins in coastal HABs can be splashed airborne by the surf. Individuals near the shoreline may have allergic responses such as a runny nose, sneezing, watery eyes, difficulty breathing and coughing. People who ingest shellfish carrying the toxins may suffer from gastroenteritis, myalgia, vertigo and tremors. In sea mammals, brevetoxin attaches to the brain, resulting in confusion and possible death. According to studies performed by members of the National Marine Fisheries Science Center in Seattle, WA and the National Institute of Environmental Health Services Science Center in Miami, FL., brevetoxin poisoning is attributed to the stranding and mass deaths of manatees and sea lions and the beaching of whales.

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