Krill and zooplankton are harvested in enormous quantities for aquaculture feed and omega-3 supplements, raising emerging welfare questions about these numerically vast animals.
Krill welfare science is in its earliest stages. While the evidence for sentience in krill is uncertain, the astronomical numbers involved mean that even a small probability of welfare relevance translates to enormous moral weight. More immediately, krill conservation for ecosystem services - including as prey for whales, seabirds and fish - has clear indirect animal welfare implications.