The sheer scale of farmed fish production — hundreds of billions of individuals annually — makes fish aquaculture welfare improvements among the highest total-impact welfare interventions available, even when per-individual improvements are modest.
Scale considerations transform fish welfare from a niche concern to one of the highest-priority welfare issues available. Improvements in salmon stunning protocols, sea lice management, stocking density, and handling that affect even a small proportion of welfare outcomes multiply across hundreds of millions of individuals to produce enormous total welfare impacts. The scale argument is not that each individual fish matters less — it is that the aggregate effect of systematic welfare improvements across an industry of this magnitude is extraordinary. Directing welfare advocacy and research funding toward aquaculture welfare improvements based on this scale consideration represents a highly effective allocation of limited welfare resources.