The objective of the Ecological risk assessment (ERA) are twofold: (1) to evaluate risk posed to aquatic organisms and piscivorous birds and mammals exposed to toxic substances in the Sheboygan River and Harbor, and (2) to derive concentrations of PCBs and other COCs in sediment that would be protective of the Sheboygan River ecosystem as assessed through surrogate receptor species. In addition, this ERA includes recommendations regarding the monitoring that will be needed to establish a baseline prior to remedial action and to assess long-term remedy effectiveness (Appendix H). The focus of this ERA is to estimate the present level of risk to the aquatic organisms and piscivorous birds and mammals of the Sheboygan River and Harbor from exposure to contaminated sediments, water, and biota.