Sea Otters Once Escaped Extinction. Can They Survive Forever Chemicals?

Sea otters are one of the Pacific Ocean's most beloved animals, but new research suggests they face a growing threat from PFAS, also called ‘forever chemicals.’ In this episode, we explore a study that found every sea otter examined by biologists along the coast of British Columbia contained PFAS contamination, with the highest concentrations detected in animals found near urban areas and busy shipping lanes.We explain why sea otters are much more than charismatic marine mammals. As a keystone species, they help control sea urchin populations, allowing kelp forests to flourish. Those underwater forests provide habitat for countless marine species, su pport fisheries, reduce coastal erosion and capture significant amounts of carbon. Scientists are concerned that if PFAS pollution weakens sea otter populations, the entire coastal ecosystem could be affected.The episode also examines what PFAS are, why they are known as "forever chemicals," how they enter the marine food web, and the health problems they have been linked to in both wildlife and humans. We also look at the remarkable recovery of sea otters after they were nearly hunted to extinction during the fur trade and why pollution may become one of the next major challenges to their long-term survival.Key points:1:04 - Why should we care about sea otters?2:16 - Near-extinction of sea otters in the early 1900s.3:19 - Partial recovery following legal protections.4:02 - Pollution has replaced hunting as one of the main threats.4:26 - ‘Forever chemicals’ found in sea otters.5:14 - Health impacts of PFAS in sea otters.Links to more information:Price et al., 2025. Concentrations of per- and polyfluoroalkyl substances in Canadian sea otters (Enhydra lutris) are higher near urban centers. Environmental Toxicology and Chemistry, 45(1): 80-91.Gregr et al., 2020. Cascading social-ecological costs and benefits triggered by a recovering keystone predator. Science, 368(6496): 1243-1247.Kannan, Perrotta and Thomas, 2006: Association between perfluorinated compounds and pathological conditions in southern sea otters. Environmental Science & Technology, 40(16):4943-4948.Shukla et al., 2023. The diversity if animals identified as keystone species. Ecology and Evolution, 13(10):e10561.PFAS - Environmental Working Group infoPFAS - European Commission infoPFAS - U.S. EPA info Get full access to Nature Signals at ruththornton.substack.com/subscribe