Abstract:
A Slocum glider was deployed in the eastern Gulf of Mexico off Tampa Bay in January 2017. As the glider traversed its transit path, it collected measurements at various depths from ~2 m to near the seafloor or up to 200 m. While the glider was deployed at sea, it surfaced and communicated to an onshore control station at predetermined intervals. A decimated selection of vehicle and science measurement is transmitted during these surface transmissions, and the relevant data became available through a USF web site. After the glider’s recovery at the end of the deployment, the complete measurement suite was downloaded from the vehicle and processed and made available through the USF site including a national data archive. The measurements in this data set included water column biomass estimates and the raw echo sounder water column backscatter intensity measurements. Other data sets for this deployment include environmental water quality parameters, acoustic tag telemetry receiver detections, and passive acoustic recordings.
The glider was deployed on 2017-01-03 at the 30 m isobath. It attempted to transit northwest along the Gulfstream Natural Gas Pipeline; however, currents to the south prevented significant northward progress and eventually pushed the glider well to the south. It was recovered well south of Tampa Bay, off Longboat Key, on 2017-01-13.
The suite of related datasets includes results from gliders M66, M69, M70, and M72.
Glider M66: water quality variables (FL.x707.000:0001, https://doi.org/10.7266/N72N50PF), tag telemetry (FL.x707.000:0002, https://doi.org/10.7266/n7-ccc2-s109), and echosounder backscatter intensity (FL.x707.000:0003, https://doi.org/10.7266/n7-9yq5-w169).
Glider M69: water quality variables (FL.x707.000:0004, https://doi.org/10.7266/n7-n30g-bw27); acoustic tag telemetry receiver detections (FL.x707.000:0005, https://doi.org/10.7266/n7-406m-ak69); echosounder backscatter intensity (FL.x707.000:0007, https://doi.org/10.7266/n7-4skm-bj34), and passive acoustic recordings (FL.x707.000:0006, https://doi.org/10.7266/n7-5y6c-sj73).
Glider M70: water quality variables (FL.x707.000:0010, https://doi.org/10.7266/g51f95wz), and tag telemetry (FL.x707.000:0008, https://doi.org/10.7266/p2ymsrp4).
Glider M72: water quality variables (FL.x707.000:0011, https://doi.org/10.7266/ehj8evgw) and tag telemetry (FL.x707.000:0009, https://doi.org/10.7266/9va17amx).
Suggested Citation:
Lembke, Chad, David Mann, Susan Lowerre-Barbieri, Chris Taylor, and Steven Murawski. 2025. Eastern Gulf of Mexico glider deployment M69 (2017-01-03 – 2017-01-13) – echo sounder water column backscatter intensity. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-4skm-bj34
Purpose:
Demonstration of fisheries-applicable datasets obtained by underwater gliders, including tag telemetry receivers, passive acoustic recordings, and echo sounder derived water column acoustic backscatter.
Data Parameters and Units:
NASC [m^2/nmi^2], depth [m], date [YYYYMMDD], time [HH:MM:SS.SSSS], latitude [decimal degrees N], longitude [decimal degrees E], backscatter.
Methods:
Based on echo sounder results, water column biomass was calculated based the Nautical Area Scattering Coefficient. The NASC calculation is the sum of all backscatter in an ensonified volume (in this case, the water column under the glider, excluding the seabed, along a 100 m length of travel), translated to the surface area sampled (2D). The Nautical Area converts to units of scattering per square nautical mile (instead of per square meter).
Provenance and Historical References:
Lembke, Chad; Lowerre-Barbieri, Susan; Mann, David; Taylor, J. Christopher (2018). Using three acoustic technologies on underwater gliders to survey fish. Marine Technology Society Journal 52(6), 39-52. DOI:
https://doi.org/10.4031/mtsj.52.6.1
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