Coral Reef Fish & Human Disease

The fish that live on coral reefs are regularly caught by fisherman and served as meals around the world. Such delicacies include snapper, sea bass and barracuda. In certain parts of the world it is possible that the consumption of these fish can lead to disease, as some fish have been contaminated by marine toxins.

  1. Marine Toxins

    • Marine toxins are natural occurring chemicals that can contaminate seafood. There is no change to the seafood with regards to looks, smell and taste. Disease can result in humans when such seafood is eaten. The types of disease most commonly caused by eating coral reef fish, are ciguatera poisoning and paralytic shellfish poisoning.

    Ciguatera Poisoning

    • Ciguatera poisoning can be caused by eating contaminated coral reef fish. The toxins that cause ciguatera poisoning, ciguatoxins are progressively concentrated as they move up the food chain from their origins in microscopic sea plants. In the predatory coral reef fish such as barracuda, grouper, sea bass, snapper and mullet these concentrations can be particularly high due to their high position in the food chain. These fish are caught by sport fisherman off the reef . Symptoms usually occur between a few minutes and 30 hours after eating contaminated fish. These symptoms are non-specific (not only associated with ciguatera poisoning) and usually clear in one to four weeks, with the poisoning rarely being fatal.

    Paralytic Shellfish Poisoning

    • Paralytic shellfish poisoning is caused by different toxins to ciguatera poisoning. The toxin that causes it is know to concentrate in certain shellfish of colder coastal waters, however it has also been reported in the warmer waters of central America. Tropical shellfish that can cause the disease include crabs and lobsters. Symptoms can occur anywhere from 15 minutes to 10 hours after eating contaminated shellfish. The symptoms are non specific, but progress from mild symptoms, worsening and in some cases leading to death from respiratory failure in two to 25 hours.

    Diagnosis

    • Diagnosis comes from recognizing the symptoms and knowledge of the history of what the patient has eaten. If there is leftover fish from the meal then this can help to identify the presence of a toxin. Laboratory testing is not usually necessary as it requires specialized techniques and equipment.

    Treatment

    • There is no specific treatment for the marine poisoning caused by eating tropical fish. Intravenous mannitol has been suggested for the treatment of ciguatera poisoning but otherwise the only treatment that can be provided is supportive care.