Monitoring programs are an important component of Marine Protected Area (MPA) management, providing requisite information on the state of, and changes in, protected ecosystems. Monitoring is required to gauge the efficacy of MPAs towards their conservation objectives and provides information needed to evaluate the benefits provided to biodiversity from restricted access. However, in Nova Scotia’s coastal zone, there is a lack of baseline data, including fish diversity and community structure in macrophyte beds, which makes monitoring intractable. In 2017, the Eastern Shore Islands was identified as a coastal Area of Interest (AOI) for the potential establishment of an MPA. In 2018 an overview was conducted, detailing the spatial and temporal ecological attributes of the AOI. This information revealed a unique coastal ecosystem associated with a dense archipelago and relatively natural seascape. The abundance of plant and algal biogenic habitats within the area was assumed to host a diversity of juvenile fish species. The primary objective of this project is to begin development of a long-term biodiversity monitoring program in the Eastern Shore Islands and other coastal Areas of Interest for conservation planning. We propose implementing this program with the use of direct (beach seines, scuba diving, and stable isotope sampling) and indirect (environmental DNA - eDNA) sampling. Environmental DNA (eDNA) is a useful tool to examine marine biodiversity in a non-invasive way, on a small spatial scale. eDNA can be easily collected and filtered and is becoming increasingly cost efficient to sequence and may be a useful marine protected area monitoring tool. While eDNA generally yields comparable results to traditional sampling techniques in terms of biodiversity captured, little is known on how eDNA signals fluctuate across years (or even days to weeks). We will compare species detections using eDNA metabarcoding to visual surveys (scuba and seine nets) to census eelgrass beds across the coastal zone, providing a baseline and time series of species diversity on which to base long-term monitoring. This project will generate inventories of eelgrass bed locations, and fish and invertebrate diversity within eelgrass beds. We additionally collect fish length distribution data to examine seasonal and inter-annual trends in size structure over time. The data generated from direct and indirect sampling will provide a comprehensive and ongoing catalog of species diversity and community structure in coastal eelgrass beds, as well as best-practices for sampling eDNA in the coastal environment. Cite this data as: Jeffery, N.W., Pettitt-Wade, H., Van Wyngaarden, M., and Stanley, R.R.E. Maritimes Coastal Biodiversity Monitoring Program – Beach Seining. Published: December 2023. Coastal Ecosystems Science Division, Maritimes region, Fisheries and Oceans Canada, Dartmouth NS. https://open.canada.ca/data/en/dataset/dbbcb23a-d018-4b70-b8ec-89997aded770