Restoring damaged and declining eelgrass in the San Juan Archipelago: a pioneering program using seeds

The importance of eelgrass (Zostera marina) comes alive through the Coast Salish people's cultural stories and practices. The presence of these marine flowering plants is important for culturally iconic species such as the Dungeness Crab and Pacific Herring. In the San Juan Archipelago, loss of historical spawning sites for herring appears to coincide with eelgrass decline. In an effort to offset eelgrass decline, the Puget Sound Eelgrass Recovery Strategy outlines a program that includes a plan to 'restore and enhance damaged or declining eelgrass beds'. The uprooting and replanting of adult eelgrass plants is commonly used as a restoration technique. However, throughout the range of eelgrass in the Northern Hemisphere the collection and dispersal of eelgrass seeds has been put forward as a low-cost and effective alternative. This technique is proposed because, after pollination, fertilization, and seed development, eelgrass flowering heads disperse a yearly seed rain, and these seeds populate available habitat either within the bed or a distant location. When seeds settle on the ocean floor in suitable conditions, seedlings sprout, and new patches form. In spring 2020, we launched a pilot program at the Friday Harbor Laboratories, University of Washington, to restore eelgrass in the nearshore region of Bell Point in Westcott/Garrison Bays using seeds. In this poster presentation we illustrate a step wise description of our program that includes methods to: 1) estimate seed to ovule ratios to guide flowering head collection; 2) harvest flowering heads while limiting damage to the donor population; 3) capture the season of peak seed release; 4) efficiently gather and store seeds before planting; and 5) deliver seeds to a restoration site. We will also provide an estimate of human hours, supplies and construction materials needed to replicate our program at other sites in the Salish Sea.