What does the recovery stage of self-purification focus on?

The recovery stage of self-purification focuses on the resurgence of aquatic life, particularly the increase in fish populations. During this stage, a body of water that has been impacted by pollution undergoes a natural restoration process. As pollutants are broken down and removed, the environmental conditions improve, facilitating the return of various forms of aquatic life, including fish.

Higher levels of dissolved oxygen are typically a byproduct of this recovery, as bacteria and microorganisms metabolize organic materials, but the prominent indicator of recovery is the return and increase in fish and other aquatic species, reflecting a healthier ecosystem. Recognizing the rise in populations of sensitive species like fish serves as a clear signal that the water quality is improving and that the ecosystem is on the mend.