Ecosystem-level Impacts of Oil Spills: A Review of Available Data with Confidence Metrics for Application to Ecosystem Models

Oil spills remain a persistent threat to marine life, but their long-term effects across different taxonomic groups are poorly understood. Few ecosystem models can predict the long-term effects of oil spills in marine systems due to data gaps and complexity of both marine systems and oil as a contaminant mixture. To support the development of regional ecosystem models, we reviewed the available data on the effects of oil spills on the marine ecosystem, and present and apply a process for selecting and assessing data on contaminant stressors. Our region of interest is the Salish Sea, a marginal sea in the Pacific Ocean, spanning the USA and Canada. We collate and present the data currently available on the impacts of polycyclic aromatic hydrocarbons (PAHs), oil-derived persistent organic pollutants, across multiple ecological groups within the Salish Sea. We then apply a scoring system to gauge the usefulness of those data for modelling the ecosystem impacts of these contaminant stressors. Within the available data on ecological processes and impacts of PAH, we identify data gaps in PAH uptake rates and metabolism across most biological groups, and in the overall effects of contaminants on marine mammals, sharks, and seabirds. These data gaps highlight research priorities that can enhance long-term risk assessments of oil-related contaminants on the marine ecosystem, and support broader modelling efforts and environmental management efforts in the Salish Sea and beyond.