Water quality parameters in aquaculture systems directly determine the welfare outcomes for fish in a fundamental and measurable way.
Water quality is the foundational welfare determinant for farmed fish in ways that have no parallel in land animal farming. Fish are submerged in their environment — there is no escape from poor water quality, and physiological stress from suboptimal oxygen, temperature, and chemistry is continuous and cumulative. Welfare improvements through water quality management require monitoring, management capacity, and sometimes infrastructure investment, but the return in individual fish welfare across hundreds of billions of farmed fish is enormous.