California sea lions have recovered strongly under Marine Mammal Protection Act protections, but entanglement in fishing gear, harmful algal blooms, and human disturbance continue to create welfare challenges for individuals and pups.
Sea lions with domoic acid toxicosis from harmful algal bloom consumption experience seizures, disorientation, and brain damage — symptoms similar to status epilepticus that cause genuine acute suffering. Entangled sea lions carry fishing gear that causes progressive tissue damage, restricts movement, and ultimately kills through infection or inability to feed. Stranded pups during El Niño events are starving — their mothers cannot find adequate prey within nursing range, forcing premature weaning before pups have adequate body reserves. The Marine Mammal Center and other rehabilitation facilities address individual welfare harms through rescue and medical treatment, but systemic welfare improvement requires addressing harmful algal bloom causes (nutrient pollution, climate warming) and reducing fishing entanglement through gear modification.