Antarctic krill are the keystone prey species supporting whales, seals, and penguins across the Southern Ocean, and industrial harvesting concentrated near feeding grounds raises ecosystem welfare concerns.
While krill are small crustaceans whose individual sentience is debated, the ecosystem welfare implications of krill harvesting are substantial. Concentrating fishing near penguin and seal breeding colonies during the austral summer directly competes with dependent predators at their most vulnerable period. Penguins rearing chicks and seals nursing pups require access to krill aggregations close to shore. Depleting these local concentrations forces adults to travel further and return with less food, increasing chick and pup mortality. This represents welfare harm to millions of sentient vertebrates. Whether krill themselves experience suffering is uncertain, but their role as a welfare keystone species justifies strong management precaution.