It is usually caused by a combination of warm weather, calm water and algae blooms.
There are serious algae blooms, and it is not advisable to come into contact with the water.
The green algae blooms support the fish as food and produce oxygen.
As an algae bloom dies, the microscopic cells break down.
In late summer, the algae blooms make fishing difficult.
No one knows for sure why the algae blooms have become so persistent and overwhelming.
"I study algae blooms," he said in a newspaper report.
More damage is done when the algae blooms begin to die.
The county has also approved $400,000 to investigate the causes of recent algae blooms.
Public and private hierarchies are seeing an algae bloom of chief something else officers.