Watershed Management: Watershed Planning
A fish kill is an event where dead or dying fish are found in a waterbody. There are many factors, both natural and human-induced, that can contribute to a fish kill. In Florida, the majority of fish kills are caused by one or more natural causes. The most common causes are related to physical processes (e.g. cold temperatures), water chemistry changes (e.g. low dissolved oxygen levels), and biological processes (e.g. spawning fatalities, fish parasites, or toxic algae blooms). Human induced fish kills have been reduced in recent years due to pollution prevention practices. When a direct human induced fish kill occurs it is usually due to an unintentional chemical leak into a waterbody. However, some fish kills are indirectly caused by humans. These instances are usually associated with a decrease in water quality that leads to low oxygen levels or changes in other water chemistry parameters. This usually occurs as result of increased nutrient loading to a system from urban run-off and a subsequent algae bloom.