A custom designed Klein 7180 towed sonar was deployed from the NOAA Ship FAIRWEATHER to determine its value of acoustic backscatter as a habitat defining character. A Sonardyne Fusion USBL system was used to estimate underwater positioning of the towfish using an omnidirectional Wideband submini beacon operating in external trigger mode. Navigation data were logged in QINSy and exported into a text file. The towfish positions were then smoothed in Matlab using a custom script that implemented a weighted Hamming filter, using a window of 11 data points. These points represent the smoothed USBL navigation data for the Klein 7180 towfish during the Arctic reconnaissance transit from Dutch Harbor to Kotzebue. These smoothed towfish navigation data, however, will NOT ultimately be reinserted back into the sonar files for mosaicking and analysis. Rather, another navigation smoothing routine will be used for the final product.

A custom designed Klein 7180 towed sonar was deployed from the NOAA Ship FAIRWEATHER to determine its value of acoustic backscatter as a habitat defining character. A Sonardyne Fusion USBL system was used to estimate underwater positioning of the towfish using an omnidirectional Wideband submini beacon operating in external trigger mode. Navigation data were logged in QINSy and exported into a text file. The towfish positions were then smoothed in Matlab using a custom script that implemented a weighted Hamming filter, using a window of 11 data points. These points represent the smoothed USBL navigation data for the Klein 7180 towfish during the Arctic reconnaissance transit from Dutch Harbor to Kotzebue. These smoothed towfish navigation data, however, will NOT ultimately be reinserted back into the sonar files for mosaicking and analysis. Rather, another navigation smoothing routine will be used for the final product.

A custom designed Klein 7180 towed sonar was deployed from the NOAA Ship FAIRWEATHER to determine its value of acoustic backscatter as a habitat defining character. A Sonardyne Fusion USBL system was used to estimate underwater positioning of the towfish using an omnidirectional Wideband submini beacon operating in external trigger mode. Navigation data were logged in QINSy and exported into a text file. The towfish positions were then smoothed in Matlab using a custom script that implemented a weighted Hamming filter, using a window of 11 data points. These points represent the smoothed USBL navigation data for the Klein 7180 towfish during the Arctic reconnaissance transit from Dutch Harbor to Kotzebue. These smoothed towfish navigation data, however, will NOT ultimately be reinserted back into the sonar files for mosaicking and analysis. Rather, another navigation smoothing routine will be used for the final product.

A custom designed Klein 7180 towed sonar was deployed from the NOAA Ship FAIRWEATHER to determine its value of acoustic backscatter as a habitat defining character. A Sonardyne Fusion USBL system was used to estimate underwater positioning of the towfish using an omnidirectional Wideband submini beacon operating in external trigger mode. Navigation data were logged in QINSy and exported into a text file. The towfish positions were then smoothed in Matlab using a custom script that implemented a weighted Hamming filter, using a window of 11 data points. These points represent the smoothed USBL navigation data for the Klein 7180 towfish during the Arctic reconnaissance transit from Dutch Harbor to Kotzebue. These smoothed towfish navigation data, however, will NOT ultimately be reinserted back into the sonar files for mosaicking and analysis. Rather, another navigation smoothing routine will be used for the final product.

A custom designed Klein 7180 towed sonar was deployed from the NOAA Ship FAIRWEATHER to determine its value of acoustic backscatter as a habitat defining character. A Sonardyne Fusion USBL system was used to estimate underwater positioning of the towfish using an omnidirectional Wideband submini beacon operating in external trigger mode. Navigation data were logged in QINSy and exported into a text file. The towfish positions were then smoothed in Matlab using a custom script that implemented a weighted Hamming filter, using a window of 11 data points. These points represent the smoothed USBL navigation data for the Klein 7180 towfish during the Arctic reconnaissance transit from Dutch Harbor to Kotzebue. These smoothed towfish navigation data, however, will NOT ultimately be reinserted back into the sonar files for mosaicking and analysis. Rather, another navigation smoothing routine will be used for the final product.

Polyline depicting the extent along the transit where multibeam sonar data were acquired using the Reson 7111 and 8160 mulltbeam sonar systems. Multibeam echosounder data were acquired and processed according to NOAA OCS hydrographic standards.

The Free Fall Cone Penetrometer Test (FFCPT) is a technique for geotechnical profiling of sub aqueous sediments. It was developed based on proven piezocone penetration test (CPT) theory and algorithms, with modifications to the manner of deployment and recovery. The instrument is designed to free fall through the water column, eventually impacting the seabed, recording penetration data at a high sample rate (2,000 Hz). This permits high resolution characterization of the sediment layering and material properties such as grain size and undrained shear strength. In addition to seabed characterization, the instrument can also be used for underway sound velocity profiling.

The broad scope of the Essential Fish Habitat (EFH) mandate requires an efficient process for describing and mapping the habitat needs of federally managed species. For example, research indicates surficial sediments affect the distribution and abundance of many groundfish species, yet traditional sampling with grabs and cores is impractical over areas as large as the Bering Sea shelf. Acoustic tools are suitable for large-scale surveying and show great promise as a substitute for direct-sampling methods, but they have not been proven useful for EFH purposes.

The broad scope of the Essential Fish Habitat (EFH) mandate requires an efficient process for describing and mapping the habitat needs of federally managed species. For example, research indicates surficial sediments affect the distribution and abundance of many groundfish species, yet traditional sampling with grabs and cores is impractical over areas as large as the Bering Sea shelf. Acoustic tools are suitable for large-scale surveying and show great promise as a substitute for direct-sampling methods, but they have not been proven useful for EFH purposes.

The Resource Assessment and Conservation Engineering (RACE) Division of the Alaska Fisheries Science Center (AFSC) conducted a survey in the eastern Bering Sea (EBS) to evaluate short-term impacts of bottom trawls on soft-bottom benthic habitats and to describe the recovery process. This was a multi-year project which follows earlier studies of long-term bottom trawling impacts in the same general region. The study area was within the Crab and Halibut Protection Zone 1 in Bristol Bay (management area 512; approximately latitude 58 degrees north and longitude 160 degrees west. In general, at-sea work was divided into three phases: (1) integrated biological and geological sampling before experimental trawling, (2) experimental trawling and (3) integrated biological and geological sampling after experimental trawling. Survey activities were conducted aboard the 47.2 meter (155 ft) chartered vessel Ocean Explorer. This was a commercial fishing vessel modified to support the research activities. Activity during phase 1 consisted of side scan assessments of seafloor morphology with an interferometric Klein 5410 side scan sonar towfish during night wheel watches, and epifauna trawls and collection of infauna and sediment grabs during daylight hours. All samples from a particular gear were collected in succession, so as to minimize time spent installing and configuring gear during phases (1) and (3). Assessment activities after the impact phase were a repeat of activities prior to experimental trawling.