Sea otters are a keystone species whose predation on sea urchins maintains kelp forest ecosystems, and their conservation has cascading welfare benefits for the many species that depend on healthy kelp habitats.
Individual sea otters face welfare challenges from oil contamination, entanglement in fishing gear, shark predation, and prey depletion. Oil spills cause rapid hypothermia as contaminated fur loses its insulating capacity, forcing otters to abandon the water and exposing them to extreme energy demands. Entangled otters drown or suffer injury from gear restricting movement. Individual welfare of otters is tightly linked to ecosystem health — otters in degraded kelp habitats must work harder to find food, reducing body condition and reproductive success. The keystone role of otters means their welfare has multiplicative effects: protecting individual otters maintains the ecosystem services that support thousands of other species across the kelp forest.