This dataset shows the cruise tracklines for the acoustic surveys completed along the 58‐km long Assateague barrier island stretching from the Ocean City inlet in Maryland, down past Chincoteague Island in northern Virginia. The data was collected June 20th-25th, 2014 and May 12th - 21th, 2015. Full coverage side-scan sonar and partial coverage bathymetry data were collected using an EdgeTech 6205 Multiphase Echosounder. In total, 73 square kilometers were mapped at primarily at 100m line spacing and 80 m swath range per channel (to allow overlap between lines).

This dataset shows 2 m depth contours within the study area. The contours were created using the contour feature within the Spatial Analyst Toolbox in ArcMap (v 10.2.2). Contours were manually edited where necessary to clean up artifacts in the dataset. The input dataset was bathymetry data processed to 50 cm horizontal resolution that was collected June 11th-16th, 2015.

This dataset shows the NPS park boundary for FIIS within Moriches Bay. The boundary was manually delineated from the boundary illustrated on NOAA chart 12352.

Surveys of the bathymetry and backscatter intensity of the sea floor south of Long Island, New York, were carried out in November 1998 using a Simrad EM1000 multibeam echosounder mounted on the Canadian Coast Guard ship Frederick G. Creed. The purpose of the multibeam echosounder surveys was to explore the bathymetry and backscatter intensity of the sea floor in several areas off the southern coast of Long Island along the 20-meter isobath. Survey areas offshore of Fire Island Inlet, Moriches Inlet, Shinnecock Inlet, and southwest of Montauk Point were about 1 kilometer (km) wide and 10 km long. The area was mapped by the U.S. Geological Survey with support from the Canadian Hydrographic Service and the University of New Brunswick.

These data present the processed bathymetry mosaic for FIIS. The bathymetry data was collected June 11th-16th, 2015. The acoustic sonar survey was conducted using a EdgeTech 6205, a Multi-Phase Echo sounder system. This combined bathymetry and dual-frequency sidescan sonar system is optimized for shallow water surveying and is capable of acquiring bathymetry swath widths up to 8x the water depth. The sonar system was bow-mounted to a 28-ft pontoon survey vessel customized for shallow water surveying, including having a draft of less than one foot. Data was collected using GeoDas software developed by Ocean Imaging Consultants (OIC) and monitored topside in real-time to ensure quality of data and full-coverage sidescan was being achieved. The data were collected in association with an Applanix POS MV system to assure positional accuracy and to correct for vessel motion (pitch, roll, heave). The survey was designed to acquire full-coverage sidescan data and partial coverage bathymetry. As such, the survey was composed of parallel track lines with line spacing of 35 to 50 m and a sonar swath range of 50 m (25 m per side) to ensure overlap with adjacent lines. The raw sidescan and bathymetry records were processed using OIC CleanSweep software (Version 3.8.0, Build #263). For bathymetry, the processing following standard techniques of first correcting for tide, sound velocity, and vessel motion. Filters were then applied to remove outlier soundings. The resulting mosaic presents water depths of the survey area. All of the acoustic data were examined manually to confirm quality and accuracy. The horizontal coordinate system was set to UTM Zone 18N and bathymetry data was processed to 50cm pixel resolution.

Conductivity, Temperature, and Depth (CTD) Profiles associated with submerged mapping cruises, FIIS

Line shapefile showing the track lines of the acoustic mapping at Sandy Hook, NJ between July 2015 and August 2015. The side scan sonar survey was done simultaneously with the bathymetry swath survey and used an EdgeTech Model 4125 Towfish bow-mounted from Lookdown at 400 and 900 kHz. The 4125 Towfish utilizes EdgeTech’s Full Spectrum CHIRP technology to produce higher resolution images than a non-CHIRP system. EdgeTech Discovery Software was used to acquire the side scan sonar data using the JSF format at a resolution of about 2.3 cm. All JSF files collected using EdgeTech’s Discover Software were processed using John Gann’s Chesapeake Technology SonarWiz5. Dimensions of contacts should be considered accurate to +/- 30% of the measured dimensions. This system also records the direct arrival intensity data.

This dataset presents the processed sidescan mosaic for Fire Island National Seashore. The acoustic sonar survey was conducted using a EdgeTech 6205, a Multi-Phase Echo sounder system. This combined bathymetry and dual-frequency sidescan sonar system is optimized for shallow water surveying. The sonar system was bow-mounted to a 28-ft pontoon survey vessel customized for shallow water surveying, including having a draft of less than one foot. Data was collected using GeoDas software developed by Ocean Imaging Consultants (OIC) and monitored topside in real-time to ensure quality of data and full-coverage sidescan was being achieved. The data were collected in association with an Applanix POS MV system to assure positional accuracy and to correct for vessel motion (pitch, roll, heave). The survey was designed to acquire full-coverage sidescan data and partial coverage bathymetry data. As such, the survey was composed of parallel track lines with line spacing of 35 to 50 m and a sonar swath range of 50 m (25 m per side) to ensure overlap with adjacent lines. The raw sidescan and bathymetry records were processed using OIC CleanSweep software (Version 3.8.0, Build #263). All of the acoustic data were examined manually to confirm quality and accuracy. For sidescan, processing followed standard techniques of bottom-tracking the data and then applying angle-varying gains (AVG) and look-up tables (LUT) as necessary to correct for water column returns, arrival angle, and contrast to produce color-balanced sidescan sonar images. The native images are displayed as an inverse gold color scale, with pixel values ranging from zero (dark gold) to 255 (white). The lighter pixels indicate hard acoustic returns and represent the presence of hard surficial sediments (e.g. coarse sand, cobbles, and boulders), whereas darker pixels represent the presence of soft sediments, which tend to absorb sound to a greater degree. The horizontal coordinate system was set to UTM Zone 18N and sidescan data was processed to 25cm pixel resolution.

Benthic Macrofauna Sampling Data used to construct benthic habitat maps for FIIS. Data were collected during ground-truth surveys involving the collection of surficial grab samples of the seafloor and sediment profile imagery (SPI). Grab samples for analysis of macrofaunal community structure were collected in triplicate within Otis Pike and Sunken Forest to allow for more robust statistical analyses and to account for small-scale spatial variability that may be present. Single grab samples were taken at each site within East Breach to allow for a broader distribution of sample sites throughout the area. All samples were processed on board the vessel at the time of collection to ensure quality of data and avoid sample degradation. Each sample was sieved through a 0.5 mm mesh and captured macrofauna were retained and preserved in a Rose-Bengal solution to be processed at a designated lab. All individuals were counted and identified to the species level. SPI images were collected to corroborate and complement the acoustic and grab sample data. Images were taken at each grab sample site and also along a series of planned transects designed to cross boundaries identified in the sidescan mosaics. All deployments of the camera were done in triplicate, resulting in six images per site (one deployment of the camera captures two images ten seconds apart).

Benthic habitat maps were developed for the Otis Pike and Sunken Forest study areas following the top-down mapping approach, for which habitat map units are geologically defined based on the presumption that geologic environments or features contain distinct biological assemblages. The resulting habitats are classified according to the CMECS framework and are referred to as “biotopes.” The term “biotope” is specific in that it integrates biotic-abiotic characteristics to offer more ecologically meaningful information. In this study, biotopes reflect the relationship between macrofaunal communities and geological features of their associated environments within the defined map units. The resulting biotopes are considered preliminary because the relationships identified have not been repeatedly demonstrated over time, as this study represents the first of its kind within FIIS.