Marine Biotoxins 

Marine biotoxins, produced by phytoplankton usually during HAB 

events, are some of the most potent toxins in the world and 

extremely dangerous. For some toxins, doses at the microgram 

per kilogram level are more than sufficient to kill. When enough 

toxin is accumulated in fish or shellfish, small amounts of cooked 

or raw tissue can kill a human. For example, recorded HAB 

events have produced enough PSP toxin in mussels that the 

consumption of one or two small mussels could have killed a normal, healthy adult 

human. While some toxins are very potent, i.e., requiring only small amounts to produce

illness or death, other less potent toxins may accumulate to such high levels that they 

still can cause harm. For example, the total dose of domoic acid to produce a minimal 

toxic effect is fairly high (i.e., tens of milligrams) but it can accumulate in sufficient 

quantities in shellfish to produce deadly results (ranging from mild stomach distress to 

permanent brain damage and even death). 

The risk of poisoning from consumption of fish or shellfish is serious and of concern to 

public health authorities in all coastal environments. This is true both in the United 

States and worldwide. The risk and threat to public health is so great that virtually all 

countries have instituted some form of risk management plan to deal with marine 

biotoxins. These "sanitation" plans are difficult to design and implement because the 

properties of the toxins are only poorly understood, not to mention the origins and 

responsible alga may also not be known. 

Toxins in the Pacific Region 

NOAA's region of responsibility in the Pacific encompasses an area that stretches literally 

from the North Pole to south of the equator. Within this region a myriad of toxins occur 

that range from temperate toxins, such as 

Paralytic Shellfish Poison or PSP (the syndrome 

is caused by suite of toxins called the saxitoxins 

or gonyautoxins) and domoic acid poisoning, to 

tropical toxins such as ciguatera fish poisoning 

(the toxin is called ciguatoxin). The properties 

of these toxins are also quite different, ranging 

from the "fat soluble" ciguatoxin to the water 

soluble toxins of domoic acid and PSP. 

While these toxins originate from 

phytoplankton, these algae come from 

ecological niches that are all very different from 

each other. In the tropics, ciguatera poisoning 

is caused essentially by reef dwelling fish and 

the responsible phytoplankton is a dinoflagellate 

(Gambierdiscus toxicus) that lives on coral reefs 

and other surfaces. In temperate waters, the 

PSP toxins are produced by the dinoflagellate 

Alexandrium catenella and domoic acid by 

diatoms in the genus Pseudo-nitzschia. All of 

these differences (chemical, ecological, and 

biological) make it difficult to design simple, 

one stop monitoring techniques for these toxins and poisoning syndromes that would be 

applicable throughout the region. 

To read more about marine biotoxins and methods of detection and analyses, please use

the navigation bar to the right. 

For more in depth descriptions of the toxin syndromes, we suggest that you might want 

to look at the extensive monograph by Bruce W. Halstead ("Poisonous and Venomous 

Marine Animals of the World" (Darwin Press). .

 

 

 

 

 

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