Shrimp aquaculture involves some of the highest stocking densities of any farmed animal — with billions of individuals affected, improving conditions has massive welfare implications.
The welfare case for farmed shrimp is built on uncertain but non-trivial evidence of sentience and robust evidence of density-related physiological stress. Even setting aside sentience questions, the mass mortality events driven by overcrowding and disease represent poor animal stewardship. If shrimp are sentient — and growing evidence suggests some capacity for pain-like experiences — the scale of shrimp farming makes it potentially one of the largest sources of animal suffering on the planet. The precautionary principle argues strongly for reducing stocking densities, improving water quality, and researching more humane killing methods as a matter of urgency.