What is the most common reason for herbicide-related fish kills?

The most common reason for herbicide-related fish kills is the lowering of dissolved oxygen levels in the water. When herbicides are applied, they can lead to rapid growth of aquatic plants, which may subsequently die off and decompose. This decomposition process consumes a significant amount of dissolved oxygen in the water, creating hypoxic conditions that can be lethal to fish and other aquatic organisms.

Fish rely on dissolved oxygen for survival, and when levels drop below a certain threshold, they can experience stress or even die from asphyxiation. The relationship between herbicide application, excessive plant growth, and subsequent oxygen depletion underscores the importance of carefully managing herbicide use to prevent harmful impacts on aquatic ecosystems.

Understanding this mechanism is crucial for anyone engaged in aquatic pest management, as it highlights the interconnectedness of chemical use and aquatic life health. This knowledge can guide practitioners in selecting appropriate strategies that minimize risks to fish populations and maintain a balanced aquatic ecosystem.