The first successful use of a robot seed planter in seagrass restoration

Richard Kazimierz Frank Unsworth, Emma Fox, Sam Rees, Chris Oakes

The global decline of seagrass meadows has intensified efforts to restore these foundational coastal ecosystems, yet restoration remains constrained by the inability to deliver seeds consistently, accurately, and efficiently over ecologically meaningful spatial scales. While underwater robotics have increasingly been proposed to overcome these operational bottlenecks, there is currently little empirical evidence demonstrating that robotic planting can achieve successful ecological restoration outcomes under field conditions. We evaluated the first application of a robotic underwater seed planter for seagrass restoration. A tethered remotely operated vehicle, equipped with a precision injection system, was used to deliver a bentonite-seed slurry into subtidal sediments at a target burial depth of 3–4 cm within a restoration site in Dale, West Wales. Over 31.5 hours of field operations, the system deployed 25,550 Zostera marina seeds across approximately 200 m². Eighteen months after planting, monitoring confirmed the establishment of at least 102 m² of seagrass meadow, representing approximately 51% of the original planted area. The established vegetation supported a mean shoot density of 56 ± 23 shoots m⁻² and included reproductive shoots, demonstrating the completion of the reproductive cycle and indicating progression towards a self-sustaining meadow. The robotic platform achieved consistent seed placement while removing many of the operational limitations associated with diver-based restoration. These findings provide the first quantitative evidence that robotic precision planting can successfully establish seagrass meadows under field conditions. Although broader ecological constraints on restoration remain, robotic seed delivery represents an important technological advance that could substantially improve the scalability, repeatability, and safety of seed-based marine habitat restoration.