Zooplankton and small marine invertebrates are killed in vast numbers through fishing and pollution, with growing philosophical debate about whether their welfare matters morally.
If any invertebrates are capable of sentient experience, marine zooplankton and benthic invertebrates represent a numerically vast welfare consideration. Bottom trawling destroys entire invertebrate communities — sponges, worms, echinoderms, crustaceans — that take decades to recover. The philosophical debate about expanding our moral circle to include small invertebrates is active and unresolved. The precautionary approach suggests reducing unnecessary harm even under uncertainty about sentience.