What role do herbicides play in aquatic pest management?

Herbicides are specifically designed to control unwanted aquatic vegetation, making them a critical tool in aquatic pest management. By targeting and suppressing the growth of invasive or undesirable plant species, herbicides help maintain the balance of aquatic ecosystems. This control is essential because excessive vegetation can lead to issues such as reduced oxygen levels, blocked light penetration, and disrupted habitats for native aquatic life.

In contrast, the other options do not accurately describe the primary function of herbicides. For example, while enhancing oxygen levels or promoting fish growth may be important for ecosystem health, these are not the direct effects of herbicides. Additionally, increasing water temperature is unrelated to the action of herbicides, which focus solely on aquatic plant management.