Classification of Marine Toxins

In this classification of marine toxins post we have briefly explained about marine toxins, definition, sources, classification of marine biotoxins, diagnosis and treatment.

Marine Biotoxins

Marine biotoxins are produced by microorganisms that live in aquatic environments. Molluscs, crustaceans, and different fish concentrating and bioaccumulating these chemicals eventually find their way into the human gastrointestinal tract. Foodborne infections and a constellation of neurologic and gastrointestinal signs, and other symptoms, can result from ingesting marine biotoxins.


In both temperate and tropical environments, phytoplankton and shellfish poisons are common. Shellfish can become poisonous without blooms, and phytoplankton traditionally linked with poisons does not always create marine biotoxins.

At the same time, different species releasing different marine biotoxins could be present. Paralytic Shellfish Poisoning (PSP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic Shellfish Poisoning (NSP), Ciguatera Fish Poisoning (CFP), and Amnesic Shellfish Poisoning (ASP).

Classification of Marine Toxins

Paralytic Shellfish Poisoning

Paralytic Shellfish Poison (PSP) is a naturally occurring marine biotoxin produced by some tiny algae species. Dinoflagellates of the genera Alexandrium, feeding molluscan bivalves and other shellfish, concentrate the marine biotoxins.

Within hours of ingesting shellfish tainted with dangerous quantities of saxitoxin, victims experience gastrointestinal distress and neurological symptoms ranging from benign circumoral paresthesias and limb tingling to ataxia, dysphagia, and mental abnormalities. Toxins cannot be removed by cooking, so be sure you get your fish from a reliable source.

Diarrhetic Shellfish Poisoning

Diarrhetic (or diarrheal) shellfish poisoning is caused by swallowing marine biotoxins containing shellfish (such as mussels, cockles, scallops, oysters, and whelks).

The most common species affected and associated with diarrhetic shellfish illnesses are mussels; rare diseases have also been associated with clams and scallops.

The onset of DSP symptoms is quick, starting 30 minutes to 15 hours after consuming contaminated shellfish. Symptoms usually appear within one to two hours. The recovery period is within three days.

Neurotoxic Shellfish Poisoning

Neurotoxic Shellfish Poisoning (NSP) is a sickness induced by eating brevetoxin-contaminated molluscan shellfish.

Biotoxins accumulate in shellfish (such as clams, oysters, whelks, mussels, conch, coquinas, and other filter-feeding mollusks) according to their natural food chain patterns.

NSP is diagnosed based on the clinical signs and symptoms, and a carefully elicited history includes recent molluscan shellfish ingestion. Symptoms can appear anywhere from a few minutes to 18 hours after consuming contaminated shellfish.

Ciguatera Fish Poisoning

Ciguatera fish poisoning (CFP) is a foodborne sickness that affects people all over the world. Humans get sick from eating reef fish that contain ciguatoxins, which are naturally occurring marine biotoxins.

CFP occurs at different rates in different parts of the world. CFP affects 10,000–50,000 persons each year who reside in or visit tropical and subtropical areas, however due to under-reporting, the exact incidence of CFP is difficult to determine.

CFP is linked to symptoms and indicators in the gastrointestinal (GI), cardiovascular, neurological, and neuropsychiatric systems. Symptoms and indicators of gastrointestinal distress (e.g., vomiting, diarrhoea, abdominal pain, and nausea) appear 6–24 hours after eating a supposedly tasty reef fish, and usually, go away on their own within 1–4 days.

There are currently no reliable biomarkers for confirming CTX exposure in humans; while animal research suggests that CTX detection in human blood or serum maybe attainable shortly.

Amnesic Shellfish Poison

Domoic acid, often known as Amnesic Shellfish Poison (ASP), is a marine biotoxin toxin generated by the diatom Pseudo-nitzschia sp., a species of naturally occurring microscopic algae.

Shellfish are Filter feeders. They filter and devour algae and other food items by pumping water through their systems. When shellfish ingest algae that produce biotoxins, the biotoxin might build up in their tissue.

Because the algae that create the poison are usually found in coastal locations; razor clams are the most commonly impacted by Amnesic Shellfish Poison. In Puget Sound, Amnesic Shellfish Poison has been found in mussels, clams, and oysters.


Symptoms and a recent history of consuming a specific type of seafood is used to diagnose marine toxin poisoning.

Testing for the specific marine biotoxins in patient samples is usually unnecessary because it necessitates specialist procedures and equipment that are only available in specialized laboratories. It is easier to test leftover fish for the presence of the toxin.

Antihistamines an epinephrine, in addition to supportive care, effectively treat the symptoms of scombrotoxic fish poisoning.


There are no specific treatments for marine biotoxins poisoning caused by marine organisms. Treatment usually consists of preventing complications and providing emotional support until the sickness has passed. The most common consequence is dehydration induced by diarrhea and vomiting.

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