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Historical Occurrence of HABs

Several decades ago relatively few countries appeared to be affected by HABs, but now most coastal countries are threatened, in many cases over large geographic areas and by more than one harmful or toxic species.  Many countries are now faced with disturbing trends of increasing bloom incidence, larger areas affected, more fisheries resources impacted, and higher economic losses. The causes behind this expansion are debated, with possible explanations ranging from natural mechanisms of species dispersal to a host of human-related phenomena such as nutrient inputs, coastal development, aquaculture development, and climatic shifts.

While HABs may appear to many to be a recent phenomenon,  the phytoplankton species that cause HABs and their toxins are naturally occurring, and incidences of HABs and HAB-associated food poisoning are described in historical records dating back centuries.  The recent associated with combined pressures of a growing world population, food production, aquaculture development, and coastal development.

Below is a timeline outlining some examples of historical records of HABs, as well as evidence of HAB impacts in the fossil record.


1961, Monterey Bay, ASP

It is believed that Alfred Hitchcock’s iconic film, “The Birds,” was inspired by an actual event that occurred in California in August of 1961. During this event, thousands of birds along the North Monterey shore were reported to display erratic behavior, including vomiting and death. While the cause of this mortality was unknown at the time, it has been discovered that toxic Pseudo-nitzschia were present in abundance in the phytoplankton community. In subsequent years, upwelling events along the California coast have been shown to drive Pseudo-nitzschia blooms, resulting in similar instances of erratic behavior and mortality in seabirds. Read more about this event here.

1927, San Francisco, PSP

Six fatalities and over a hundred illnesses were caused by a paralytic shellfish poisoning outbreak in San Francisco in 1927. Read more about this event here.


1844, Florida

Earliest reports of red tide in Florida. Read more here.



1799, Alaska, PSP

A hunting part in southeastern Alaska became ill after eating a meal of mussels. Nearly 100 members of the party died, and based on details of the accounts it is believed that paralytic shellfish poisoning was the cause. Read more here.


1793, British Columbia, PSP

One one of the earliest reports of paralytic shellfish poisoning comes from British Columbia, where a member of Captain George Vancouver’s crew was killed after eating contaminated shellfish. Local tribes in the region had taboos on eating shellfish during bioluminescent dinoflagellate blooms. Read more here.


1774, Vanuatu, Ciguatera

After eating fresh fish caught off the coast of Vanuatu (South Pacific), members of Captain Cook’s crew experienced illness characterized by upset stomach, vomiting, and weakness. These symptoms are indicative of ciguatera poisoning, which occurs when fish accumulate ciguatoxins, produced by members of the dinoflagellate genus Gambierdiscus. Read more here.


1606, Vanuatu, Ciguatera

An early report of ciguatera was recorded by the Spanish explorer Fernandez de Quiros in 1606 during a voyage in the New Hebrides (Vanuatu). This account described poisoning of his sailors after consuming snapper (Pargos sp.). Read more here.

~1000 B.C.

~1000 B.C., Egypt, Anoxia

There is a reference to algal blooms in the Bible, ‘ . . . all the waters that were in the river were turned to blood. And the fish that was in the river died; and the river stank, and the Egyptians could not drink of the water of the river’ (Exodus 7: 20–1). The scenario described here fits the description of a nontoxic bloom which created anoxic conditions that led to a fish kill. Read more here.

~2.6 million years ago

~2.6 million years ago, Bird mortality

Geologic records from the Gulf Coast of Florida indicate several mortality events of cormorants, fish, and other birds in the late Pliocene. These remains were found with depositions of dinoflagellate cysts, indicating that these die-offs were caused by toxic blooms. Read more about this event here.

~47 million years ago

~47 million years ago, Cyanobacteria

A group of well-preserved mammal fossils, dated from 47 million years ago, indicates that a large mammal mortality occurred in Messel, Germany. These fossils include the remains of primitive horses, birds and bats, and are accompanied by geologic evidence of cyanobacterial blooms. Read more here and find the original paper here.



Bargu, S., Silver, M.W., Ohman, M.D., Benitez-Nelson, C.R. and Garrison, D.L., 2012. Mystery behind Hitchcock’s birds. Nature Geoscience5(1), pp.2-3.

de Queirós, P.F., y Bermúdez, L.D.B., de Leza, G.G., de Torquemada, J., de Torres, L.V., y Tobar, D.D.P., de Castro, F. and Arias, J.L., 1904. The Voyages of Pedro Fernandez de Quiros, 1595-1606 (Vol. 14). Hakluyt society. [EBook #41200], Release Date: October 27, 2012. 

Doherty, M.J., 2005. Captain Cook on poison fish. Neurology65(11), pp.1788-1791.

Emslie, S.D., Allmon, W.D., Rich, F.J., Wrenn, J.H. and Susan, D., 1996. Integrated taphonomy of an avian death assemblage in marine sediments from the late Pliocene of Florida. Palaeogeography, Palaeoclimatology, Palaeoecology124(1-2), pp.107-136.

Hallegraeff, G.M., 2003. Harmful algal blooms: a global overview. Manual on Harmful Marine Microalgae, pp. 25-49.

Koenigswald, W. V., Braun, A. 2004. Cyanobacteria and seasonal death: A new taphonomic model for the Eocene Messel lake. Palaontologische Zeitschrift, 78(2), pp. 417-424.

Kumar-Roiné, S., Matsui, M., Pauillac, S. and Laurent, D., 2010. Ciguatera fish poisoning and other seafood intoxication syndromes: a revisit and a review of the existing treatments employed in ciguatera fish poisoning. The South Pacific Journal of Natural and Applied Sciences28(1), pp.1-26.

Magaña, H.A., Contreras, C. and Villareal, T.A., 2003. A historical assessment of Karenia brevis in the western Gulf of Mexico. Harmful Algae2(3), pp.163-171.