California sea lions face welfare harms from fishing gear entanglement, gunshot wounds from fishery conflicts, and domoic acid poisoning from harmful algal blooms.
Sea lion welfare involves multiple overlapping human-caused harms. Entanglement in fishing line and nets causes lacerations that deepen as animals grow or struggle, eventually cutting to bone if not removed. Domoic acid poisoning causes acute neurological distress — seizures, disorientation, and beach stranding — and can cause permanent brain damage in survivors. Gunshot wounds inflicted by fishers protecting their catch cause severe pain and often lead to delayed death from infection. Rehabilitation of stranded sea lions requires intensive veterinary care including surgical removal of embedded lines and treatment of domoic acid neurological damage. The frequency of these welfare events is increasing with climate change driving more frequent harmful algal blooms and the expansion of fisheries into sea lion range.