Submerged aquatic vegetation: overview of monitoring techniques used for identification and determination of spatial distribution in European coastal waters

Coastal waters are highly productive and diverse ecosystems, often dominated by marine Submerged Aquatic Vegetation (SAV) and strongly affected by a range of human pressures. Due to their important ecosystem functions, both researchers and managers have for decades investigated changes in SAV abundance and growth dynamics to understand linkages to human perturbations. In European coastal waters monitoring of marine SAV communities traditionally combines diver observations and/or video recordings to determine e.g. spatial coverage and species composition. While these techniques provide very useful data, they are rather time consuming, labour intensive and limited in their spatial coverage. In this manuscript, we compare traditional and emerging remote sensing technologies used to monitor marine SAV, which include satellite and occupied aircraft operations, aerial drones and acoustics. We introduce these techniques and identify their main strengths and limitations. Finally, we provide recommendations for researchers and managers to choose the appropriate techniques for future surveys and monitoring programs. This article is protected by copyright. All rights reserved.