Canada is investing in its large Marine Protected Area (MPA) network, spanning approximately 805,000 km², to preserve marine biodiversity and promote healthy, functional, and resilient marine ecosystems. However current biodiversity sampling methods are inadequate to monitor biodiversity within a network of this size. The project team proposes to use environmental DNA (eDNA) metabarcoding to evaluate and optimize marine monitoring survey designs. The results of this project will be the first quantitative evaluation of eDNA survey design in a marine setting and will provide a foundation for decisions in monitoring investment using this technology in the Canadian MPA network.