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Economic Impacts of Harmful Algal Blooms (HABs)

For a printable .pdf of this fact sheet, click here.

Economic effects of HABs in the U.S. are at least $82 million/year *

Commercial Fisheries Impacts:
$38 million/year

Public Health Costs of Illnesses:
$37 million/year

Recreation and Tourism Impacts:
$4 million/year

Coastal Monitoring & Management:
$3 million/year

* Hoagland and Scatasta (2006). Based on subset of outbreaks in 1987-2000.

Some harmful algae produce potent toxins which cause illness or death in humans and other organisms, including endangered species. Other harmful algae are non-toxic to humans and wildlife but degrade ecosystems by forming such large blooms that they can adversely affect corals, seagrasses, and organisms living on the sea-bottom. Human health and ecosystem impacts of HABs and management responses to lessen those impacts can have significant economic and sociocultural consequences.

Coastal HAB events have been estimated to result in economic impacts in the U.S. of at least $82 million/year with the majority of impacts in the public health and commercial fisheries sectors (Hoagland and Scatasta 2006). This estimate is conservative due in part to a lack of quantitative information on the environmental impacts of HAB events, and a lack of documentation of sociocultural impacts (such as degradation of cultural practices and values, increased reliance on social services, loss of recreational opportunities, and shifts in livelihoods). Moreover, unreported illnesses, reductions in property values, lost seafood sales due to unfounded consumer fears (the “halo effect”), and lost revenue from some untapped fisheries are just a few examples of economic costs not accounted for in this estimate. Impacts of a single event on individual economic sectors (e.g. commercial fisheries) can be large (see map below) , highlighting the likelihood that this estimate is very conservative.

Mouseover the numbered states on the map to get information on HAB events
(text will appear below map)

Map of US highlighting HAB economic effects by state
get Washington HAB events get Hawaii HAB events get Texas HAB events get Florida HAB events get Maine HAB events

Lost Shellfish Sales in Maine and Massachusetts:
as much as $23 million in 2005

closure sign in the town of Bourne, MA
Photo: J.Kleindinst WHOI

In 2005, an historic Alexandrium fundyense bloom (also called red tide) in New England resulted in extensive and, in some locations, unprecedented closures of shellfish harvesting to prevent paralytic shellfish poisoning (PSP) in human consumers. Closures are estimated to have caused approximately $18 million in lost shellfish sales in Massachusetts (Jin et al. 2008) and $4.9 million in Maine (Jin et al. 2008, Athearn 2007). These estimates do not account for indirect effects on business linked to the shellfish industry or reduced spending due to lost income. Furthermore, offshore shellfish fisheries that are indefinitely closed due to shellfish toxicity likely result in millions of dollars of lost revenue.

Karenia brevis Impacts in Florida:
$19-32 million per year

Florida fish kill

The Florida HAB species, Karenia brevis (also called red tide), blooms almost every year, most often off the west coast of Florida. Karenia brevis toxins can kill fish, birds, and marine mammals; are a threat to human health; and can cause respiratory irritation in beachgoers or people living or working near the water. Steidinger et al. (1999) estimated economic impacts from these blooms to be at least $15-25 million per year (or $19-32 million in 2007 dollars). An exceptionally bad event in 1971, similar in magnitude but shorter in duration than the 2005 Karenia bloom, was estimated to cause about $20 million in economic impacts (or $100 million in 2007 dollars), primarily to the tourism industry (Habas and Gilbert 1974).

Impacts of Karenia brevis in Galveston, Texas:
$10 million in 2000

texas fish kill
Photo: TPWD

In summer of 2000, a Karenia brevis outbreak and associated fish kills were reported in Texas coastal waters. The fish kills persisted in many areas through November. Most Texas coastal waters were closed to shellfish harvesting until the end of November to protect human consumers from Neurotoxic Shellfish Poisoning (NSP). Some areas remained closed until January 2001. A case study of the 2000 red tide in Texas estimated that economic impacts were at least $9.9 million in Galveston County alone due to commercial oyster fishery closures, lost tourism, and costs of beach cleanup (Evans and Jones 2001).

Impacts on commercial, subsistence, and recreational fisheries in the Pacific Northwest:
$10-12 million in 2002/03

beach cleanup
Photo: WA DFW
Washington state

In 2002-03, high levels of domoic acid in razor clams along the Pacific Coast resulted in a season long closure of the fishery in Washington to protect human consumers from Amnesic Shellfish Poisoning (ASP). In addition, high toxin levels caused the first commercial Dungeness crab fishery closure due to algal toxins since 1991. This event resulted in at least $10-12 million in lost revenue. The oyster, Dungeness crab, and razor clam fisheries in Washington are cumulatively valued at $72 million/year for the local economies and are important for commerce, recreation, and the culture of local coastal tribes.

Impacts of Macroalgae in Maui, HI:
$20 million/year

coral reef Hawaii

Macroalgal blooms, which adversely impact coral reefs and local aesthetics, are a recurring problem along the Kihei coast in Maui. These blooms potentially cost Hawaii more than $20 million in lost revenue each year, due to reductions in real estate value and hotel business as well as increased clean-up costs (NOAA Economic Statistics Report). Van Beukering and Cesar (2004) estimated that continued algal blooms could result in additional losses of $16 million annually over the next several decades.

What is NOAA Doing?

  • NOAA, through extramural funding (ECOHAB, MERHAB, and CSCOR Event Response ) and intramural research programs, is working to minimize public health, sociocultural, and economic impacts by improving prediction and monitoring, developing methods of control, and improving public understanding.
  • NOAA is also funding research to assess economic impacts at local scales and to assess the costs and benefits of mitigation strategies, which were both identified by HARRNESS and HARR-HD as research needs to improve focus and cost-effectiveness of mitigation strategies.


Anderson DM, Hoagland P, Kaoru Y, White AW. 2000. Estimated Annual Economic Impacts from Harmful Algal Bloom (HABs) in the United States, Technical Report WHOI-2000-11 Woods Hole Oceanographic Institute, Woods Hole, Mass.

Anderson DA, Keafer BA, McGillicuddy DJ, Mickelson MJ, Keay KE, Libby PS, Manning JP, Mayo CA, Whittaker DK, Hicky JM, He R, Lynch DR, Smith KW. 2005. Initial observations of the 2005 Alexandrium fundyense bloom in southern New England: General Patterns and Mechanisms. Deep-Sea Research II. 52: 2856-2876.

Athearn K. 2007. Economic losses from closure of shellflish harvesting areas in Maine. For reference, total impacts due to all harvesting closures (including flood closures) in Maine http://www.umm.maine.edu/assets/docs/appliedResearch/eco_losses_shellfish_jan08.pdf

Ayers D, Reed H. 2004. Managing important recreational and commercial shellfish fisheries around harmful algal blooms In T.W. Droscher and D.A. Fraser (eds). Proceedings of the 2003 Georgia Basin/Puget Sound Research Conference. Session 4F. http://www.psat.wa.gov/Publications/03_proceedings/start.htm [February 2004]

Evans G, Jones L. 2001. Economic Impact of the 2000 Red Tide on Galveston County, Texas A Case Study. Final Report. TPWD No. 666226. Texas Parks and Wildlife.

Habas, E.J., and C.K. Gilbert. 1974. The economic effects of the 1971 Florida red tide and the damage it presages for future occurrences. Environmental Letters 6(2):139–147.

HARRNESS. 2005. Harmful algal research and response: A national environmental science strategy: 2005-2015. Ramsdell JS, Anderson DM, Glibert PM, eds. Washington DC: Ecological Society of America.

HARR-HD. 2006. Bauer M., ed. Harmful Algal Research and Response: A Human Dimensions Strategy, National Office for Marine Biotoxins and Harmful Algal Blooms, Wood Hole Oceanographic Institution, Woods Hole, MA., 58 pp.

Hoagland P, Scatasta S. 2006. The economic effects of harmful algal blooms. In E Graneli and J Turner, eds., Ecology of Harmful Algae. Ecology Studies Series. Dordrecht, The Netherlands: Springer-Verlag, Chap. 29.

Jin D, Thunberg E, Hoagland P. 2008. Economic impact of the 2005 red tide event on commercial shellfish fisheries in New England. Ocean and Coastal Management. 51(5): 420-429.

NOAA Economic Statistics Report

Steidinger KA, Landsberg JH, Tomas CR, Burns JW. 1999. Harmful algal blooms in Florida. Unpublished technical report submitted to the Florida Harmful Algal Bloom Task Force, Florida Marine Research Institute, 63pp.

Van Beukering P, Cesar H. 2004. Ecological Economic Modeling of Coral Reefs: Evaluating Tourist Overuse at Hanauma Bay and Algae Blooms at the Kihei Coast, Hawaii. Pacific Science, Vol. 58, No. 2, pp. 243-260.