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HABs & Biotoxins

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

OVERVIEW

PHYTOPLANKTON

MARINE BIOTOXINS

WEST COAST HABS

• Detection & Analyses

• Domoic Acid Poisoning

• Paralytic Shellfish Poisoning

• Diarrhetic Shellfish Poisoning
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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