Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>This dataset contains the seagrass beds delineated in 2021 in southern Maine, from Eliot to Cape Elizabeth. Polygons were screen digitized from aerial imagery flown at low tide on June 29, 2021. Imagery was captured using a Vexcel Eagle 80-mm Mark 3 aerial camera mounted on a fixed wing aircraft and flown at an elevation of approximately 9,500 feet. Polygons were refined based on field verification efforts that took place between August 26 and October 7, 2021. Field verification was carried out on foot, by canoe with view tubes and an SAV rake in the Spinney Creek backwater and parts of the Spurwink River, and by boat using a Maine DEP vessel (20-foot Maritime Skiff with a 115 horse outboard motor), Ocean Systems High-Definition (HD) underwater video camera and SeaViewer 950 Sea-Drop Analog underwater video camera, and Eos Positioning Systems Arrow Gold GNSS GPS systems that pair wirelessly to Android powered ruggedized field tablets capable of submeter accuracy. </SPAN></P><P><SPAN>Each seagrass polygon is named by individual bed with a section and two character section abbreviation based on general geographic location (1=Piscataqua River [PR], 2=York River [YR], 3=Kennebunk [KB], 4=Saco River [SA], 5=Scarborough River [SB]) and a sequential number moving from southwest to northeast along the coast. Each polygon was also assigned a percent cover category and percent based on those established by Orth et al. (1991), where 1=0-10% cover (very sparse), 2=10-40% cover (sparse), 3=40-70% cover (moderate), 4=70-100% cover (dense). </SPAN></P><P><SPAN>This seagrass polygon shapefile also contains fields for whether the bed was field verified (Y=yes or N=no) and whether there is corresponding underwater video footage (Y=yes, N=no). Field verified beds were verified only in part, meaning one or more transects were placed along the perimeter of the bed to confirm seagrass presence and aerial signatures; bed boundaries were rarely verified in their entirety. Underwater video is present for most of the field verified beds but is lacking in some areas due to battery life of the recording equipment and less than ideal field conditions that prohibited towing the camera for extended periods of time. In these instances, field observations were still possible and camera drops to check conditions were often used. A video column corresponds to the named underwater video file, and species and comment fields are also incorporated in this dataset. Species are only noted if directly observed by underwater video or by visual observations in shallow water. Widgeon grass was observed only in the Spinney Creek backwater off the Piscataqua River, and Eelgrass was the dominant vascular species in all other locations. Based on these observations and the limited extent of widgeon grass, it is likely all beds without a designated species name are eelgrass. </SPAN></P></DIV></DIV></DIV>
Service Item Id: af4c834d3fc84352bb159611c353d15b
Copyright Text: Seagrasss mapping was produced for the State of Maine Department of Environmental Protection. Orthophotos for this effort were acquired by James W. Sewall and Bluesky Geospatial was subcontracted for aerial imagery acquisition. Normandeau Associates, Inc. was the primary contractor for seagrass delineation.
Description: <DIV STYLE="text-align:Left;"><P STYLE="margin:0 0 7 0;"><SPAN><SPAN>This dataset contains the seagrass beds delineated in 2022 in Casco Bay, from Cape Elizabeth to Cape Small in Phippsburg. Polygons were screen digitized from aerial imagery flown at low tide on July 16th, 2022. Imagery was captured using a Vexcel Eagle 80-mm Mark 3 aerial camera mounted on a fixed wing aircraft and flown at an elevation of approximately 9,500 feet. Polygons were refined based on field verification efforts that took place between August 29 and September 27, 2022. Field verification was carried out on foot by Old Brunswick Road at the New Meadows River and by boat using a Maine DEP vessel (20-foot Maritime Skiff with a 115 horse outboard motor), Ocean Systems High-Definition (HD) underwater video camera and SeaViewer 950 Sea-Drop Analog underwater video camera, and Eos Positioning Systems Arrow Gold GNSS GPS systems that pair wirelessly to Android powered ruggedized field tablets capable of submeter accuracy. </SPAN></SPAN></P><P STYLE="margin:0 0 7 0;"><SPAN><SPAN>Each seagrass bed is named by sequential number moving from southwest to northeast along the coast, then back southeast along the islands, which is provided in the ‘Name’ column. These beds are further divided into polygons by percent cover. Polygons are labeled with a unique identifier consisting of sequential numbers in the ‘Id’ column. A singular bed can consist of several Ids. Percent cover categories and percentages are based on those established by Orth et al. (1991), where 1=0-10% cover (very sparse), 2=10-40% cover (sparse), 3=40-70% cover (moderate), 4=70-100% cover (dense). </SPAN></SPAN></P><P STYLE="margin:0 0 11 0;"><SPAN>This seagrass polygon shapefile also contains fields for whether the bed was field verified</SPAN><SPAN> in 2022</SPAN><SPAN> (Y=yes or N=no) and whether there is corresponding underwater video footage (Y=yes, N=no). Field verified beds were verified only in part, meaning one or more transects were placed along the perimeter of the bed to confirm seagrass presence and aerial signatures; bed boundaries were not verified in their entirety. Field verification refers to whether the bed (Name field) was visited, it does not account for individual parts of the bed (Id field) with differing cover classes, though often verification occurred in more than one cover class per bed. Underwater video is present for most of the field verified beds but is lacking in some areas due to video transfer errors. </SPAN><SPAN>The</SPAN><SPAN> video column corresponds to the named underwater video file, which corresponds to transect name</SPAN><SPAN>.</SPAN><SPAN> </SPAN><SPAN>S</SPAN><SPAN>pecies and comment fields are also incorporated in this dataset. Species are only noted if directly observed by underwater video or by visual observations in shallow water. Widgeon grass was observed only in the New Meadows River area off of Old Brunswick Road from samples washed up near shore.</SPAN></P><DIV><P><SPAN /></P></DIV></DIV>
Service Item Id: af4c834d3fc84352bb159611c353d15b
Copyright Text: Seagrass mapping was produced for the State of Maine Department of Environmental Protection. Orthophotos for this effort were acquired by James W. Sewall and Bluesky Geospatial was subcontracted for aerial imagery acquisition. Normandeau Associates, Inc. was the primary contractor for seagrass delineation.
Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>This dataset contains the seagrass beds delineated in 2023 in the Midcoast Region, from Small Point in Phippsburg to Marshall Point in Port Clyde. </SPAN></P><P><SPAN>Polygons were screen digitized from aerial imagery flown at low tide on July 7, August 2, August 3, and August 6, 2023. Imagery was captured using a Vexcel Eagle 80-mm Mark 3 aerial camera mounted on a fixed wing aircraft and flown at an elevation of approximately 9,500 feet. Polygons were refined based on field verification efforts that took place between August 14 and October 11, 2023. Field verification was carried out by boat using a Maine DEP vessel (20-foot Maritime Skiff with a 115 horse outboard motor, 12' Tracker with 5 horse outboard motor, or canoe), SeaViewer Admiral Pro High-Definition (HD) georeferenced underwater videography package with SeaViewer 6000 Sea Drop underwater video camera, and Juniper Systems Geode GNS3S GNSS GPS system capable of submeter accuracy that paired wirelessly to Samsung Tab Active3 ruggedized field tablets.</SPAN></P><P><SPAN>Each contiguous seagrass bed is named by sequential number moving from west to east along the coast, which is provided in the ‘Bed_Name’ column. These beds are further divided into polygons by percent cover. Polygons are labeled with a unique identifier consisting of sequential numbers in the ‘Polygon_ID’ column. A singular bed can consist of several polygons IDs. Percent cover categories and percentages are based on those established by Orth et al. (1991), where 1=0-10% cover (very sparse), 2=10-40% cover (sparse), 3=40-70% cover (moderate), 4=70-100% cover (dense).</SPAN></P><P><SPAN>This seagrass polygon shapefile also contains fields for whether the bed was field verified in 2023 (Y=yes or N=no) and whether there is corresponding underwater video footage (Y=yes, N=no). Field verified beds were verified only in part, meaning one or more transects were placed along the perimeter of the bed to confirm seagrass presence and aerial signatures; bed boundaries were not verified in their entirety. Field verification refers to whether the bed (Bed_Name field) was visited, it does not account for individual parts of the bed (Polygon_ID field) with differing cover classes, though often verification occurred in more than one cover class per bed. Underwater video is present for most of the field verified beds but is lacking in some areas due to technical errors or logistical limitations on deploying video equipment. The video column corresponds to the named underwater video file, which corresponds to transect name. Species and comment fields are also incorporated in this dataset. Species are only noted if directly observed by underwater video or by visual observations in shallow water. Widgeon grass was observed only in a tributary to the Great Salt Bay, upstream of a culvert that likely restricts tidal flow. </SPAN></P></DIV></DIV></DIV>
Service Item Id: af4c834d3fc84352bb159611c353d15b
Copyright Text: Seagrasss mapping was produced by the State of Maine Department of Environmental Protection. Orthophotos for this effort were acquired by James W. Sewall and Bluesky Geospatial was subcontracted for aerial imagery acquisition and orthophotography development. The Maine Department of Environmental Protection Marine Vegetation Mapping Program completed the seagrass delineation.