Eighteen advisories were issued in 2011; an increase of an average of 7 advisories from 2005-2007 to an average of 19 during the last 4 years. This may indicate blooms are increasing in severity but may also reflect enhanced surveillance efforts.

Twenty-two advisories were issued in 2010. The bloom season began in April and ended in January, 2011.

Twenty-one heath advisories were issued in 2009, with a bloom season that extended from May to December. The number of health advisories per year increased from six in 2005 to 21 in 2009.

The number of advisories increased to 14 in 2008, and the season extended from May to January of the following year.

In 2007, eight advisories were issued between May and September. Two advisories were issued for the same water body during this period.

Eight advisories were issued in 2006; of these four occurred during the fall months.

Data from 2005 and prior years show that algae advisories were fewer in number and shorter in duration, and in some cases no public health action was taken.