Blooms of toxic or harmful microalgae, commonly called "red tides," represent a significant and expanding threat to human
health and fisheries resources throughout the United States and the world. Ecological, aesthetic, and public health impacts
include: mass mortalities of wild and farmed fish and shellfish, human intoxication and death from the consumption of
contaminated shellfish or fish, alterations of marine food webs through adverse effects on larvae and other life history stages of
commercial fish species, the noxious smell and appearance of algae accumulated in nearshore waters or deposited on beaches, and
mass mortalities of marine mammals, seabirds, and other animals.
In this report, we provide an estimate of the economic impacts of HABs in the United States from events where such impacts
were measurable with a fair degree of confidence during the interval 1987-92. The total economic impact averaged $49 million
per year, with public health impacts representing the largest component (45 percent). Commercial fisheries impacts were the next
largest (37 percent of the total), while recreation/tourism accounted for 13 percent, and monitoring/management impacts 4 percent.
These estimates are highly conservative, as many economic costs or impacts from HABs could not be estimated.