Sea otters are keystone predators of kelp forest ecosystems whose welfare faces threats from oil spills, entanglement, shark bites, and infectious disease.
Sea otter welfare harms are diverse and serious. White shark attacks cause severe traumatic injuries that may be immediately fatal or cause prolonged suffering before death. Toxoplasma infection from cat feces entering marine systems through coastal runoff causes neurological disease and death. Oil contamination destroys their fur's insulating properties causing fatal hypothermia as their elevated metabolic rate cannot compensate. Their keystone role in kelp forest ecosystems means sea otter welfare and population health has cascading benefits for entire coastal ecosystem welfare.