Innovative Techniques for Large-scale Seagrass Restoration Using Zostera marina (eelgrass) Seeds

Mechanical harvesting was an effective approach for collecting seeds, and impacts on donor beds were low. Deploying seed-bearing shoots in buoys produced fewer seedlings and required more effort than isolating, storing, and hand-broadcasting seeds in the fall. We show that viable seeds can be separated from grass wrack based on seed fall velocity and that seed survival during storage can be high (92-95% survival over 3 months). Mechanical seed-planting did not enhance seedling establishment at our sites, but may be a useful tool for evaluating restoration sites. Our work demonstrates the potential for expanding the scale of seed-based Z. marina restoration but the limiting factor remains the low rate of initial seedling establishment from broadcast seeds.