Marine Toxins


  • Ciguatera is caused by eating fish contaminated with a toxin known as ciguatoxin
  • Ciguatoxin is a neurotoxin (meaning that it attacks the nervous system)
  • Ciguatera occurs between latitudes 35° south and north, but also when fish is consumed from tropical and subtropical areas such as:
    • Florida
    • South and Central Pacific Ocean and Hawaii
    • Caribbean
    • Antilles
    • Western Atlantic Ocean
    • Indian Ocean
Attention Ciguatoxin is flavourless and odourless.
It is not destroyed by:
  • Cooking
  • Freezing
  • Drying/smoking
  • Canning


  • Digestive system: nausea, vomiting, diarrhea, abdominal cramps lasting from 24 to 48 hours.
  • Cardiovascular system: slow heart rate, drop in blood pressure
  • Nervous system (manifesting after the initial symptoms): numbness in arms, legs, mouth, throat, reversal in body temperature, headache
  • Muscle, joint and dental pain, tingling or numbness around the lips, nose, hands, feet and other areas of the skin
  • Itchy skin
  • Fatigue
  • Burning sensation on contact with cold water, sweating, chills
These symptoms can last from a few days to a few months, and sometimes even a few years.
There is no cure for ciguatera, but there are treatments that can help alleviate the symptoms.

Ciguatera poisoning prevention:

Avoid eating reef fish like:

  • Barracuda
  • Sea pike (Amber jack)
  • Mackerel
  • Moray eel
  • Snapper
  • Seabass
  • Bar
  • Sturgeon
  • Liche
  • Grouper

Scombroid poisoning

  • It’s one of the most widespread types of marine toxin poisoning in the world
  • The reaction occurs after consuming fish that contains high levels of histamine if it was not properly refrigerated or stored
  • Histamine is not destroyed by:
    • Cooking
    • Freezing
    • Drying/smoking
    • Canning
  • Symptoms are very similar to a severe allergic reaction
  • They appear a few minutes to several hours after ingestion
  • Digestive symptoms: nausea, vomiting, diarrhea, abdominal cramps
  • Other: Facial swelling, skin redness, edema, hot flashes, headache, drop in blood pressure, rapid pulse, itching, burning mouth sensation, tingling, etc.
  • Involves taking antihistamines and treating the discomfort of symptoms

Scombroid poisoning prevention:

Do not eat any fish that taste salty, peppery or tingly as it may have overly high histamine levels. In some cases, there is no unusual taste.

Fish of the scombroid family is the most frequent source:
  • Tuna
  • Skipjack
  • Mackerel
  • Herring, sardines (Clupeidae)
  • Mahi-mahi (Coryphaenidae)
Make sure the fish you are eating is fresh and was stored in a properly refrigerated area.

Marine toxins prevention:
  • Marine toxins cannot be destroyed by cooking or freezing
  • Avoid eating bivalve shellfish, especially in developing countries.

Marine toxins in bivalve shellfish

Bivalve shellfish such as clams, oysters, scallops, mussels, cockles, other shellfish such as whelk, periwinkle, and lobster and crab tomalley can accumulate harmful biotoxins, bacteria or viruses in their tissues that can cause severe illnesses such as:
  • Paralytic Shellfish Poisoning (PSP)
  • Amnesic Shellfish Poisoning (ASP)
  • Diarrhetic Shellfish Poisoning (DSP)
These are often temporary, but in more severe cases, consuming biotoxins can be fatal.

Source: Public Health Agency of Canada (
Source: Guide d’intervention santé-voyage
Source: Government of Canada:
Source: Source: Travel Medicine
The information provided is for personal use, reference and education only and is not intended to be a substitute for a Physician’s advice, diagnosis or treatment. Please consult your healthcare professional for specific information on personal health matters.