Microcystin in Lake Erie fish: Risk to human health and relationship to cyanobacterial blooms

Microcystin (MC) is a cyanobacteria-produced liver toxin that has been found in fish from Lake Erie, sometimes in excess of World Health Organization (WHO) guidelines for safe consumption. Even so, few studies have quantified MCs in Lake Erie fishes, and these studies have drawn different conclusions concerning the risk that fish consumption poses to public health. To address this gap in knowledge, we used Enzyme-Linked Immunosorbant Assay (ELISA) to evaluate the MC concentration in muscle tissue from three commonly harvested fish in Lake Erie: walleye (Sander vitreus, n = 29); yellow perch (Perca flavescens, n = 52); and white perch (Morone americana, n = 55), collected during summer 2013. Satellite remote sensing was used to compare MC concentrations in fish tissue to bloom conditions in Lake Erie at the time of harvest. We found a significant difference among mean MC concentrations in walleye (71 ng MC/g wet weight), white perch (37 ng MC/g), and yellow perch (8.1 ng MC/g). In addition, MC levels in white perch appeared to depend on local bloom conditions. While few of the fish collected contained MC in excess of WHO guidelines, our results indicate that more toxic blooms could increase MC in fish to levels that pose a greater risk to public health.