Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

► We examined leukemia prevalence in PEI clams Mya arenaria. ► Prevalence was generally higher downstream of high intensity potato farming. ► Leukemia prevalence declined with distance from source in two impacted estuaries. ► Proteins, gene expression and immunology confirm diagnosis of disease. ► Intensive potato farming may contribute to prevalence of clam leukemia in PEI.