Optimizing scalability of seeding-based restoration: survival and resettlement of juvenile kelpHabitat Restoration, Rehabilitation & Enhancement

Jurgen Valckenaere¹

¹The University of Western Australia, Australia

Restoration of kelp forests has traditionally relied on small-scale transplantation techniques, such as manually attaching adult kelp individually to the seafloor. While effective in localized settings, these methods are labour-intensive, costly, and difficult to scale. More recently, seeding-based restoration techniques have emerged as a promising approach to enhance efficiency and enable larger-scale kelp recovery efforts. This study evaluates the potential of several seeding-based restoration technique including Green Gravel, aquaculture lines, and ceramic settlement devices. Across a series of laboratory and field experiments in Western Australia, we tested the performance of kelp (Ecklonia radiata) seedling establishment and early growth under different environmental conditions, substratum types and deployment strategies. We especially focused on retention rate of the substratum and survival of juvenile’s post-deployment, while assessing cost-effectiveness and scalability of different strategies. We also investigated the resettlement potential of juvenile kelp that detached from the substratum post-deployment. Resettlement of juveniles was highest on turf-covered compared to bare rock, and under conditions of high flow. The results provide insights into how to optimize seed-based kelp restoration to overcome key bottlenecks and enable more successful and scalable recovery of degraded kelp forests.