Antarctic krill and other zooplankton are harvested in enormous quantities and play a foundational role in ocean food webs. Their potential capacity for suffering raises important questions for fisheries ethics and marine welfare.
The welfare status of krill sits at the frontier of animal welfare science. Evidence for sentience in crustaceans has strengthened considerably in recent years for larger species like lobsters and crabs; the case for smaller crustaceans like krill is weaker but cannot be dismissed given the sophistication of their sensory and behavioural capabilities. The moral arithmetic is challenging: if krill have even a small probability of experiencing something like suffering, the scale of harvest — billions of animals per year — generates enormous potential welfare cost under uncertainty. The precautionary approach — taking potential krill welfare seriously even without certainty of sentience — would reshape how we evaluate krill-based omega-3 products and aquaculture feed chains. Plant-based omega-3 from algae offers a direct welfare and environmental alternative.