The assessment of the status of eelgrass (Zostera marina) beds at the bay-scale in turbid, shallow estuaries is problematic. The bay-scale assessment (i.e., tens of km) of eelgrass beds usually involves remote sensing methods such as aerial photography or satellite imagery. These methods can fail if the water column is turbid, as is the case for many shallow estuaries on Canada’s eastern seaboard. A novel towfish package was developed for the bay-scale assessment of eelgrass beds irrespective of water column turbidity. The towfish consisted of an underwater video camera with scaling lasers, sidescan sonar and a transponder-based positioning system. The towfish was deployed along predetermined transects in three northern New Brunswick estuaries. Maps were created of eelgrass cover and health (epiphyte load) and ancillary bottom features such as benthic algal growth, bacterial mats (Beggiatoa) and oysters. All three estuaries had accumulations of material reminiscent of the oomycete Leptomitus, although it was not positively identified in our study. Tabusintac held the most extensive eelgrass beds of the best health. Cocagne had the lowest scores for eelgrass health, while Bouctouche was slightly better. The towfish method proved to be cost effective and useful for the bay-scale assessment of eelgrass beds to sub-meter precision in real time. Cite this data as: Vandermeulen H. Data of: Bay Scale Assessment of Eelgrass Beds Using Sidescan and Video -Tabusintac 2008. Published: March 2021. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S. https://open.canada.ca/data/en/dataset/d1c58bc6-69d4-47b2-bb19-988f88233900

The assessment of the status of eelgrass (Zostera marina) beds at the bay-scale in turbid, shallow estuaries is problematic. The bay-scale assessment (i.e., tens of km) of eelgrass beds usually involves remote sensing methods such as aerial photography or satellite imagery. These methods can fail if the water column is turbid, as is the case for many shallow estuaries on Canada’s eastern seaboard. A novel towfish package was developed for the bay-scale assessment of eelgrass beds irrespective of water column turbidity. The towfish consisted of an underwater video camera with scaling lasers, sidescan sonar and a transponder-based positioning system. The towfish was deployed along predetermined transects in three northern New Brunswick estuaries. Maps were created of eelgrass cover and health (epiphyte load) and ancillary bottom features such as benthic algal growth, bacterial mats (Beggiatoa) and oysters. All three estuaries had accumulations of material reminiscent of the oomycete Leptomitus, although it was not positively identified in our study. Tabusintac held the most extensive eelgrass beds of the best health. Cocagne had the lowest scores for eelgrass health, while Bouctouche was slightly better. The towfish method proved to be cost effective and useful for the bay-scale assessment of eelgrass beds to sub-meter precision in real time. Cite this data as: Vandermeulen H. Data of: Bay Scale Assessment of Eelgrass Using Sidescan and Video - Cocagne 2008. Published: November 2019. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S. https://open.canada.ca/data/en/dataset/431c815e-65f0-477b-9389-060fa41ec955

A towfish containing sidescan and video hardware was used to map eelgrass in two shallow northern New Brunswick estuaries. The sidescan and video data were useful in documenting suspected impacts of oyster aquaculture gear and eutrophication on eelgrass. With one boat and a crew of three, the mapping was accomplished at a rate of almost 10 km2 per day. That rate far exceeds what could be accomplished by a SCUBA based survey with the same crew. Moreover, the towfish survey applied with a complementary echosounder survey is potentially a more cost effective mapping method than satellite based remote sensing. Cite this data as: Vandermeulen H. Data of: Bay Scale Assessment of Eelgrass Beds Using Sidescan and Video - Shippagan 2007. Published: November 2019. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S. https://open.canada.ca/data/en/dataset/6454594e-c8f9-41c4-801a-db125b8a8875

A towfish containing sidescan and video hardware was used to map eelgrass in two shallow northern New Brunswick estuaries. The sidescan and video data were useful in documenting suspected impacts of oyster aquaculture gear and eutrophication on eelgrass. With one boat and a crew of three, the mapping was accomplished at a rate of almost 10 km2 per day. That rate far exceeds what could be accomplished by a SCUBA based survey with the same crew. Moreover, the towfish survey applied with a complementary echosounder survey is potentially a more cost effective mapping method than satellite based remote sensing. Cite this data as: Vandermeulen H. Data of: Bay Scale Assessment of Eelgrass Beds Using Sidescan and Video - Richibucto 2007. Published: October 2017. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S. https://open.canada.ca/data/en/dataset/ca7af8ba-8810-4de5-aa91-473613b0b38d

This dataset includes metrics of eelgrass size, cover, and biomass from field sites along the Atlantic coast of Nova Scotia, Canada. Field sites were located across a gradient of environmental conditions, and field sampling was conducted in July to August 2022. Eelgrass percent cover, shoot density, and plants were sampled at 10 haphazardly distributed sampling stations within each eelgrass bed at approximately the same depth. Stations were ~10m apart and at least 2m from any eelgrass-bare interface. At each sampling station eelgrass leaves in a 0.5 x 0.5m quadrat were photographed for later computer image analysis to determine percent cover. The number of shoots were then counted in a 0.25 x 0.25m quadrat, and 3 vegetative shoots were collected. Shoots were measured for leaf length, width, and weight in the laboratory. These data were used to determine allometric and cover-biomass relationships for use in non-destructive estimation of bed biomass. Cite this data as: Wong, M.C., & Thomson, J. A. Data of eelgrass (Zostera marina) plant size (length, width), cover, and biomass from the Atlantic Coast of Nova Scotia. Published: February 2025. Coastal Ecosystems Science Division, Maritimes Region, Fisheries and Oceans Canada, Dartmouth NS. For additional information please see: Thomson, J. A., Vercaemer, B., & Wong, M. C. (2025). Non-destructive biomass estimation for eelgrass (Zostera marina): Allometric and percent cover-biomass relationships vary with environmental conditions. Aquatic Botany, 198, 103853. https://doi.org/10.1016/j.aquabot.2024.103853

Bay Scale Assessment of Nearshore Habitat - Bras d'Or Lake - Eskasoni 2007 data is part of the publication Bay Scale Assessment of Nearshore Habitat Bras d'Or Lakes. A history of nearshore benthic surveys of Bras d’Or Lake from 2005 – 2011 is presented. Early work utilized drop camera and fixed mount sidescan. The next phase was one of towfish development, where camera and sidescan were placed on one platform with transponder-based positioning. From 2009 to 2011 the new towfish was used to ground truth an echosounder. The surveys were performed primarily in the northern half of the lake; from 10 m depth right into the shallows at less than 1 m. Different shorelines could be distinguished from others based upon the relative proportions of substrate types and macrophyte canopy. The vast majority of macrophytes occurred within the first 3 m of depth. This zone was dominated by a thin but consistent cover of eelgrass (Zostera marina L.) on almost all shores with a current or wave regime conducive to the growth of this plant. However, the eelgrass beds were frequently in poor shape and the negative impacts of commonly occurring water column turbidity, siltation, or possible localized eutrophication, are suspected. All survey data were placed into a Geographic Information System, and this document is a guide to that package. The Geographic Information System could be used to answer management questions such as the placement and character of habitat compensation projects, the selection of nearshore protected areas or as a baseline to determine long term changes. Vandermeulen, H. 2016. Video-sidescan and echosounder surveys of nearshore Bras d’Or Lake. Can. Tech. Rep. Fish. Aquat. Sci. 3183: viii + 39 p. Cite this data as: Vandermeulen H. Bay Scale Assessment of Nearshore Habitat Bras d'Or Lake - Eskasoni 2007. Published May 2022. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S.

Eelgrass Beds 93-95 Set: Eelgrass Sample Points is a 1:24,000-scale, point feature-based layer that depicts the locations where eelgrass (Zostera marina) was either observed or where a location would be potentially favorable for future eelgrass growth. Sample points were taken along Connecticut's coast in Long Island Sound, and in major bays, harbors and rivers along the shoreline. The point features in this layer were compiled from field research using global positioning system (GPS) equipment. Feature locations were not always exact due to equipment failure or lack of satellite reception. In those cases, points were estimated from field notes. Some point locations were corrected based on field notes or hydrography and bathymetry conditions at the sample point location. The number of field points that were altered were as follows: In 1993, 32 of 290 points (11%); in 1994, 93 of 454 points (20%); in 1995, 37 of 105 points (35%). Data compilation occurred on 17 days between 7/21/1993 and 11/16/1995; exact dates of each source's data collection are noted in the attribute table. A total of 849 point locations were surveyed. The westernmost point is Frash Pond in Stratford, Connecticut and the easternmost point is the Pawcatuck River on the Connecticut/Rhode Island Border. Eelgrass was found at 484 locations and was described as either high, medium, or low density, or simply as present or absent. Eelgrass was absent at 365 locations. Publication of the datalayer was in 1997. This layer is not updated. This layer does not represent current conditions. Observed Eelgrass Beds is a 1:24,000 scale, polygon feature-based layer that depicts the locations of observed eelgrass beds in Long Island Sound, in major rivers, and within bays, harbors and other waterbodies along Connecticut's coast. The layer is based on information from the Eelgrass Sample Points layer. It represents conditions at a particular point in time (1993 to 1995). During the 1993-95 field seasons a team of researchers from the University of Connecticut Dept. of Ecology and Evolutionary Biology led by Charles Yarish, equipped with a Global Positioning System (GPS), SCUBA, and a 20' boat surveyed over 800 potential eelgrass locations. Their GPS coordinates and field notes were used to create a point coverage entitled Eelgrass Sample Points, which was plotted and checked on a 1:24000 scale base map of the Connecticut shore. These point locations, observations, and the nearshore bathymetry were then used to delineate areas representing both observed and potential eelgrass beds. Eelgrass beds were initially digitized at 1:24,000 scale, but have been edited and revised on screen at higher resolution. Keeping in mind the temporal and spatial variability of eelgrass, beds may vary in size, shape, and density from year to year. Feature locations may not always be exact due to equipment failure or lack of satellite reception. In those cases, points were estimated from field notes. It should be noted that the Observed Eelgrass Beds layer is not a complete dataset of all observed eelgrass sites in Connecticut and/or Long Island Sound. This layer was published in 1997 and is not updated. It does not represent current conditions. There are 101 polygon features representing observed eelgrass beds in this layer. Geographic locations are as follows: westernmost areas: Clinton Harbor; easternmost areas: Little Narragansett Bay, Rhode Island waters. Observed beds range in size from .003 acre (131 sq. ft.) to 49 acres (2,136,608 sq. ft.). The total area of observed beds is 632.6 acres. Potential Eelgrass Beds is a 1:24,000 scale, polygon feature-based layer that depicts the locations of potential eelgrass beds in Long Island Sound, in major rivers, and within bays, harbors and other waterbodies along Connecticut's coast. The layer is based on information from the Observed Eelgrass Beds and Eelgrass Sample Points layers. It represents conditions at a particular point in time (1993 to 199

The park is developing a protocol to monitor the extent of eelgrass beds through remote sensing.