West Coast Soft-Shell Clams Confront Severe Contagious Cancer Outbreak

A PNRI-led study published in the Proceedings of the National Academy of Sciences reports a severe outbreak of bivalve transmissible neoplasia in Washington soft-shell clams, with infection prevalence rising from about 45% in Triangle Cove (2022) and 13% in Stanwood to roughly 75% by 2024, making it one of the region’s largest documented outbreaks. The affected clams are non-native to the West Coast, likely introduced from Atlantic populations in the 1870s. Oregon officials say the current risk to their coast is low, and shellfish movements are being tested and monitored by state agencies (WDFW and ODFW).