Developments in Eelgrass Mapping Methodology Using Hydrographic Multi-beam Sonar

TitleDevelopments in Eelgrass Mapping Methodology Using Hydrographic Multi-beam Sonar
Publication TypePoster - Conference
AuthorsNorton, AR, Dijkstra, SJ
Conference Name25th Annual Zosterapalooza
Conference DatesMarch 30
Conference LocationEPA District 1 Offices, Boston, MA
Keywordseelgrass mapping

The goal of this work is to develop a data collection and processing methodology for water column backscatter data collected with a multi-beam echo-sounder (Teledyne Odom MB1) to determine the presence or absence, percent cover, maximum depth limit, and canopy height of eelgrass beds. Acoustic eelgrass mapping is of particular use in deep waters and turbid estuaries, where aerial imagery does not reveal the necessary detail for analysis. Presented here are updates to this project, including fieldwork completed in the summer and fall of 2015. The three main updates to the project are: a more comprehensive delineation of the deep edge of eelgrass beds in Portsmouth Harbor; trials of a remotely-operated survey vehicle with the same sensor package used for our boat-based multi-beam surveys over eelgrass beds; and the extension of canopy and bottom picks further out across the swath of the multi-beam.