Donald F. Boesch, Donald A. Anderson, Rita A. Horner, Sandra
E. Shumway,Patricia A. Tester and Terry E. Whitledge. 1997. Harmful
Algal Blooms in Coastal Waters: Options for Prevention, Control
and Mitigation. NOAA Coastal Ocean Program, Decision Analysis
Series No. 10, Special Joint Report with the National Fish and
Wildlife Foundation, February 1997.
Site developer's note: genus and
species names of algae are indicated
in red, rather than standard underlining (not a webpage option
unless a link...) or italics, in order to make the names easier
to find and read.
What are Harmful Algal Blooms?
The term "harmful algal blooms" (shortened for convenience
here to HABs) has been used by the scientific community to describe
a diverse array of blooms of both microscopic and macroscopic
marine algae which produce: toxic effects on humans and other
organisms; physical impairment of fish and shellfish; nuisance
conditions from odors and discoloration of waters or habitats.
Although the use of the terms "bloom" or "red tide"
conjure up an image of algal populations so dense as to be visible,
this is not always the case with HABs. Concentrations of only
a few cells per liter of some microalgae may produce harmful toxic
This assessment focused on blooms of microscopic algae occurring
in the coastal waters of the United States which produce toxic
effects and impairment of fish and shellfish production, either
directly or indirectly, via degradation of habitats. The focus
was on a relatively few species of microscopic marine algae which
cause the following:
Blooms producing neurotoxic
shellfish poisoning (NSP). These are caused by the dinoflagellate
Gymnodinium breve and occur along
the coasts of the Gulf of Mexico, and rarely, the southeast Atlantic
Blooms causing paralytic
shellfish poisoning (PSP). Various species of the dinoflagellate
genus Alexandrium are responsible
for PSP in New England, northern California, the Pacific Northwest
"Brown tide" blooms (BTB) caused by
very small golden brown algae. These seem to be a recent occurrence
in relatively enclosed waters of southern New England, particularly
Long Island (New York) and Texas. Aureococcus
anophagefferens is responsible for similar species, Aureoumbra lagunesis, blooms in Texas
bays and lagoons.
Blooms of various species of the diatom genus
Pseudo-nitzschia produce domoic acid
that causes amnesic shellfish poisoning
(ASP). Domoic acid poisoning may also be experienced by humans,
mammals, and birds from consumption of fish and other invertebrates.
Toxin-producing species of Pseudo-nitzschia occur on the northwest,
east and Gulf coasts, but no confirmed cases of ASP have occurred
in humans in the United States.
Blooms which which
do not cause illness in humans but result in catastrophic
losses of cultured and wild fish, particularly in the Pacific
Northwest. Such blooms are caused both by the raphidophyte flagellate
Heterosigma akashiwo and by a few
species of the diatom genus Chaetoceros,
which clog fish gills.
To report problems or provide comments,
Andrew Kane (Aquatic Pathobiology Center) at:firstname.lastname@example.org
Dan Jacobs (Maryland Sea Grant)
UNIVERSITY OF MARYLAND
College of Ag & Natural Resources
Department of Veterinary Medicine
Aquatic Pathobiology Center