As shown in this table, red tides have occurred off the west coast of Florida for more than 168 years (current through 2011).
View a larger version of the timeline (PDF 282KB)
The data stored in the Florida Red Tide Historical Database are different from those found in many other long-term datasets because sampling effort varies from year to year. Not all samples are collected at fixed locations or times. Sampling effort varies with the location, extent and duration of blooms; and changes in availability of the funding that supports harmful algal bloom projects. The figure below illustrates this variation. Spikes in sampling effort correspond with copper sulfate spraying in the 1950s, marine mammal mortalities in the 1990s, and increased funding from federal sources during the last two decades.
Figure illustrating sampling effort through time between 1954 through 2011. Points represent the number of samples collected each year, while the dotted line illustrates trends in sampling effort. The gray shading indicates situations that led to increased water sampling and the dashed line indicates the reestablishment of the FWC’s Red Tide Offshore Monitoring Program, for which volunteers collect samples for red tide analysis by FWC staff.