Which environmental factor can significantly affect fish populations?

Water temperature is a crucial environmental factor that significantly affects fish populations due to its direct influence on their metabolism, reproduction, behavior, and habitat suitability. Fish are ectothermic organisms, meaning their body temperature and metabolic processes largely depend on the surrounding water temperature. Optimal temperature ranges are necessary for activities such as feeding and spawning, and deviations from these ranges can lead to stress, decreased reproductive success, and increased mortality rates.

In addition, temperature can impact the solubility of oxygen in water, which is essential for fish survival. For many species, even slight changes in temperature can disrupt their life cycles and lead to shifts in distribution. Thus, maintaining suitable water temperatures is vital for sustaining healthy fish populations and overall aquatic ecosystem health.