The most common cause of fish kills after applying aquatic herbicides is reduced levels of what?

The most common cause of fish kills after applying aquatic herbicides is reduced levels of dissolved oxygen. When herbicides are used to control aquatic plants, the decomposition of the dying plant material can lead to an increase in microbial activity. As these microbes break down the dead plants, they consume oxygen in the process, resulting in a significant drop in dissolved oxygen levels within the water. Fish and other aquatic organisms rely on adequate levels of dissolved oxygen for survival, and when these levels fall below a critical threshold, it can lead to stress or even death for fish populations.

Understanding the dynamics of dissolved oxygen is crucial for aquatic pest management because managing algal and plant biomass is a delicate balance; while controlling unwanted species can be necessary for ecosystem health, practitioners must carefully consider and mitigate the potential impacts on oxygen levels to protect fish and other aquatic life.