F2_x836_000_0005_Density_SHELF_FMG_sonar_data eng UTF8 dataset service Michael S. Williamson Texas A&M University-Corpus Christi +1 361-825-2048 HRI 213E Corpus Christi TX 78412 USA michael.williamson@tamucc.edu pointOfContact 2026-03-09 ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) 4 column row vertical temporal Trajectory - F2.x836.000.0005 - Density_SHELF_FMG_sonar_data - 513.71N, 457.36W - 2017-07-13 2021-09-28 creation 2021-09-28 issued erddap.griidc.org F2_x836_000_0005_Density_SHELF_FMG_sonar_data Kevin Boswell University of South Florida / College of Marine Science kevin.boswell@fiu.edu https://data.gulfresearchinitiative.org/data/F2.x836.000:0005 information web browser Background Information Background information from the source information originator Ernst B. Peebles epeebles@marine.usf.edu contributor After collecting egg survey samples, active-acoustic transects were collected to examine the spatial distribution of reef fish in the Florida Middle Grounds (FMG). Active acoustic data were collected with calibrated multi-frequency split-beam echosounders (Simrad EK80) operating at nominal frequencies of 38, 70 and 120 kHz. Pulse repetition rates were set to maximum, with a pulse duration of 128 ms. The 38 kHz transducer was deployed on the hull of the vessel, and the 70 and 120 kHz transducers were deployed on a pole along the side of the ship. During the survey, water temperature and conductivity were collected throughout the water column at standardized locations using a Sea-Bird 19+ Conductivity, Temperature, Depth (CTD) (Sea-Bird Electronics, Inc.) to characterize water chemistry, vertical water column structure, and derive sound-speed profiles. Sound speed and absorption coefficients were calculated to account for the effects of temperature and salinity on acoustic transmissions. Acoustic data were visualized and manually edited in Echoview 8. The echo-integral was computed for the acoustic backscatter in cells 10 m long by 10 m deep, comprising each elementary sampling distance unit (EDSU). To account for positional differences in the location of the transducers, offsets were measured and incorporated to correct the spatial location of each sample for the three transducers. A bottom-detection algorithm with a 0.5 m backstep was applied to the data and was manually edited to ensure the sea floor and reef structure were excluded from the analysis. Standard output following echo integration includes the acoustic estimate of fish density, SA (NASC, nautical area scattering coefficient, in m2 nmi?2). The echo integral was quantified for each elementary distance sampling unit to examine reef-fish density associated with each station with an echo integration threshold of -60 dB. Following echo integration, estimates of target strength (TS, in dB), which is proportional to fish length, were computed for each station to describe the length distributions of detected fish. Single targets were detected with a TS threshold of -47 dB; targets exceeding the algorithm criteria were accepted into the analysis. The single target algorithm was tuned to accept targets with echo en_velopes between 0.6 and 1.7 times the pulse length, with a maximum beam compensation of 6 dB. Given the mixed species assemblage often associated with natural and large artificial reefs in the Gulf of the relationship defined in McCartney and Stubbs (1971) was used for TS as a function of SL (in cm) following:TS = 24.5 * log10 (SL) ? 66.84. Fish density estimates were calculated as mean NASC divided by mean ?bs of a known volume of water given (EDSU) the relationship, fish density (fish m-2) = NASC/(4n*obs). unkonwn Kevin Boswell University of South Florida / College of Marine Science kevin.boswell@fiu.edu https://data.gulfresearchinitiative.org/data/F2.x836.000:0005 information web browser Background Information Background information from the source information pointOfContact 19+ 2017-07-13 2017-07-14 acoustics beam transmission bird collected conductivity coordinate crs ctd data density depthDistanceInterval depthInterval deviation distance distanceInterval echosounder end fish fish density florida fmg frequency grid grounds habitat habitatType horizontal identifier instrument instrument1 international interval mapping marine middle name number oceanography physical physical oceanography ping pingEnd pingStart platform program range reference sciences sea sea-bird shelf site siteName sonar sonde spatial standard start statistics system target temperature trajectory type underway university variable vertical weather observations theme Spawning Habitat and Early-life Linkages to Fisheries (SHELF) project time latitude longitude site_name habitat_type depth depth depth theme CF Standard Name Table v72 These data may be redistributed and used without restriction. Spawning Habitat and Early-life Linkages to Fisheries (SHELF) largerWorkCitation project Unidata Common Data Model Trajectory largerWorkCitation project eng geoscientificInformation 1 -84.27849 -84.24413 28.428877 28.636938 seconds 2017-07-13T02:59:23Z 2017-07-14T06:51:45Z -43.488624 -5.621506 Trajectory - F2.x836.000.0005 - Density_SHELF_FMG_sonar_data - 513.71N, 457.36W - 2017-07-13 2021-09-28 creation 2021-09-28 issued Kevin Boswell University of South Florida / College of Marine Science kevin.boswell@fiu.edu https://data.gulfresearchinitiative.org/data/F2.x836.000:0005 information web browser Background Information Background information from the source information originator Ernst B. Peebles epeebles@marine.usf.edu contributor After collecting egg survey samples, active-acoustic transects were collected to examine the spatial distribution of reef fish in the Florida Middle Grounds (FMG). Active acoustic data were collected with calibrated multi-frequency split-beam echosounders (Simrad EK80) operating at nominal frequencies of 38, 70 and 120 kHz. Pulse repetition rates were set to maximum, with a pulse duration of 128 ms. The 38 kHz transducer was deployed on the hull of the vessel, and the 70 and 120 kHz transducers were deployed on a pole along the side of the ship. During the survey, water temperature and conductivity were collected throughout the water column at standardized locations using a Sea-Bird 19+ Conductivity, Temperature, Depth (CTD) (Sea-Bird Electronics, Inc.) to characterize water chemistry, vertical water column structure, and derive sound-speed profiles. Sound speed and absorption coefficients were calculated to account for the effects of temperature and salinity on acoustic transmissions. Acoustic data were visualized and manually edited in Echoview 8. The echo-integral was computed for the acoustic backscatter in cells 10 m long by 10 m deep, comprising each elementary sampling distance unit (EDSU). To account for positional differences in the location of the transducers, offsets were measured and incorporated to correct the spatial location of each sample for the three transducers. A bottom-detection algorithm with a 0.5 m backstep was applied to the data and was manually edited to ensure the sea floor and reef structure were excluded from the analysis. Standard output following echo integration includes the acoustic estimate of fish density, SA (NASC, nautical area scattering coefficient, in m2 nmi?2). The echo integral was quantified for each elementary distance sampling unit to examine reef-fish density associated with each station with an echo integration threshold of -60 dB. Following echo integration, estimates of target strength (TS, in dB), which is proportional to fish length, were computed for each station to describe the length distributions of detected fish. Single targets were detected with a TS threshold of -47 dB; targets exceeding the algorithm criteria were accepted into the analysis. The single target algorithm was tuned to accept targets with echo en_velopes between 0.6 and 1.7 times the pulse length, with a maximum beam compensation of 6 dB. Given the mixed species assemblage often associated with natural and large artificial reefs in the Gulf of the relationship defined in McCartney and Stubbs (1971) was used for TS as a function of SL (in cm) following:TS = 24.5 * log10 (SL) ? 66.84. Fish density estimates were calculated as mean NASC divided by mean ?bs of a known volume of water given (EDSU) the relationship, fish density (fish m-2) = NASC/(4n*obs). ERDDAP tabledap 1 -84.27849 -84.24413 28.428877 28.636938 seconds 2017-07-13T02:59:23Z 2017-07-14T06:51:45Z -43.488624 -5.621506 tight ERDDAPtabledapDatasetQueryAndAccess https://erddap.griidc.org/erddap/tabledap/F2_x836_000_0005_Density_SHELF_FMG_sonar_data ERDDAP:tabledap ERDDAP-tabledap ERDDAP's tabledap service (a flavor of OPeNDAP) for tabular (sequence) data. Add different extensions (e.g., .html, .graph, .das, .dds) to the base URL for different purposes. download Trajectory - F2.x836.000.0005 - Density_SHELF_FMG_sonar_data - 513.71N, 457.36W - 2017-07-13 2021-09-28 creation 2021-09-28 issued Kevin Boswell University of South Florida / College of Marine Science kevin.boswell@fiu.edu https://data.gulfresearchinitiative.org/data/F2.x836.000:0005 information web browser Background Information Background information from the source information originator Ernst B. Peebles epeebles@marine.usf.edu contributor After collecting egg survey samples, active-acoustic transects were collected to examine the spatial distribution of reef fish in the Florida Middle Grounds (FMG). Active acoustic data were collected with calibrated multi-frequency split-beam echosounders (Simrad EK80) operating at nominal frequencies of 38, 70 and 120 kHz. Pulse repetition rates were set to maximum, with a pulse duration of 128 ms. The 38 kHz transducer was deployed on the hull of the vessel, and the 70 and 120 kHz transducers were deployed on a pole along the side of the ship. During the survey, water temperature and conductivity were collected throughout the water column at standardized locations using a Sea-Bird 19+ Conductivity, Temperature, Depth (CTD) (Sea-Bird Electronics, Inc.) to characterize water chemistry, vertical water column structure, and derive sound-speed profiles. Sound speed and absorption coefficients were calculated to account for the effects of temperature and salinity on acoustic transmissions. Acoustic data were visualized and manually edited in Echoview 8. The echo-integral was computed for the acoustic backscatter in cells 10 m long by 10 m deep, comprising each elementary sampling distance unit (EDSU). To account for positional differences in the location of the transducers, offsets were measured and incorporated to correct the spatial location of each sample for the three transducers. A bottom-detection algorithm with a 0.5 m backstep was applied to the data and was manually edited to ensure the sea floor and reef structure were excluded from the analysis. Standard output following echo integration includes the acoustic estimate of fish density, SA (NASC, nautical area scattering coefficient, in m2 nmi?2). The echo integral was quantified for each elementary distance sampling unit to examine reef-fish density associated with each station with an echo integration threshold of -60 dB. Following echo integration, estimates of target strength (TS, in dB), which is proportional to fish length, were computed for each station to describe the length distributions of detected fish. Single targets were detected with a TS threshold of -47 dB; targets exceeding the algorithm criteria were accepted into the analysis. The single target algorithm was tuned to accept targets with echo en_velopes between 0.6 and 1.7 times the pulse length, with a maximum beam compensation of 6 dB. Given the mixed species assemblage often associated with natural and large artificial reefs in the Gulf of the relationship defined in McCartney and Stubbs (1971) was used for TS as a function of SL (in cm) following:TS = 24.5 * log10 (SL) ? 66.84. Fish density estimates were calculated as mean NASC divided by mean ?bs of a known volume of water given (EDSU) the relationship, fish density (fish m-2) = NASC/(4n*obs). OPeNDAP 1 -84.27849 -84.24413 28.428877 28.636938 seconds 2017-07-13T02:59:23Z 2017-07-14T06:51:45Z -43.488624 -5.621506 tight OPeNDAPDatasetQueryAndAccess https://erddap.griidc.org/erddap/tabledap/F2_x836_000_0005_Density_SHELF_FMG_sonar_data OPeNDAP:OPeNDAP OPeNDAP An OPeNDAP service for tabular (sequence) data. Add different extensions (e.g., .html, .das, .dds) to the base URL for different purposes. download Trajectory - F2.x836.000.0005 - Density_SHELF_FMG_sonar_data - 513.71N, 457.36W - 2017-07-13 2021-09-28 creation 2021-09-28 issued Kevin Boswell University of South Florida / College of Marine Science kevin.boswell@fiu.edu https://data.gulfresearchinitiative.org/data/F2.x836.000:0005 information web browser Background Information Background information from the source information originator Ernst B. Peebles epeebles@marine.usf.edu contributor After collecting egg survey samples, active-acoustic transects were collected to examine the spatial distribution of reef fish in the Florida Middle Grounds (FMG). Active acoustic data were collected with calibrated multi-frequency split-beam echosounders (Simrad EK80) operating at nominal frequencies of 38, 70 and 120 kHz. Pulse repetition rates were set to maximum, with a pulse duration of 128 ms. The 38 kHz transducer was deployed on the hull of the vessel, and the 70 and 120 kHz transducers were deployed on a pole along the side of the ship. During the survey, water temperature and conductivity were collected throughout the water column at standardized locations using a Sea-Bird 19+ Conductivity, Temperature, Depth (CTD) (Sea-Bird Electronics, Inc.) to characterize water chemistry, vertical water column structure, and derive sound-speed profiles. Sound speed and absorption coefficients were calculated to account for the effects of temperature and salinity on acoustic transmissions. Acoustic data were visualized and manually edited in Echoview 8. The echo-integral was computed for the acoustic backscatter in cells 10 m long by 10 m deep, comprising each elementary sampling distance unit (EDSU). To account for positional differences in the location of the transducers, offsets were measured and incorporated to correct the spatial location of each sample for the three transducers. A bottom-detection algorithm with a 0.5 m backstep was applied to the data and was manually edited to ensure the sea floor and reef structure were excluded from the analysis. Standard output following echo integration includes the acoustic estimate of fish density, SA (NASC, nautical area scattering coefficient, in m2 nmi?2). The echo integral was quantified for each elementary distance sampling unit to examine reef-fish density associated with each station with an echo integration threshold of -60 dB. Following echo integration, estimates of target strength (TS, in dB), which is proportional to fish length, were computed for each station to describe the length distributions of detected fish. Single targets were detected with a TS threshold of -47 dB; targets exceeding the algorithm criteria were accepted into the analysis. The single target algorithm was tuned to accept targets with echo en_velopes between 0.6 and 1.7 times the pulse length, with a maximum beam compensation of 6 dB. Given the mixed species assemblage often associated with natural and large artificial reefs in the Gulf of the relationship defined in McCartney and Stubbs (1971) was used for TS as a function of SL (in cm) following:TS = 24.5 * log10 (SL) ? 66.84. Fish density estimates were calculated as mean NASC divided by mean ?bs of a known volume of water given (EDSU) the relationship, fish density (fish m-2) = NASC/(4n*obs). ERDDAP Subset 1 -84.27849 -84.24413 28.428877 28.636938 seconds 2017-07-13T02:59:23Z 2017-07-14T06:51:45Z -43.488624 -5.621506 tight ERDDAP_Subset https://erddap.griidc.org/erddap/tabledap/F2_x836_000_0005_Density_SHELF_FMG_sonar_data.subset search Subset Web page to facilitate selecting subsets of the dataset download physicalMeasurement trajectory short Density_SHELF_FMG_sonar_data time double Time siteName String site name habitatType String habitat type fish_density double fish density distance double distance to target standard_deviation double Standard Deviation vertical_range double vertical Range distanceInterval double distance interval depthInterval double depth interval pingStart double start ping number pingEnd double end ping frequency String frequency depthDistanceInterval String depth Distance Interval to target platform char platform instrument char echosounder instrument1 char Sea-Bird 19+ CTD crs int grid mapping variable for horizontal spatial coordinate reference system (CRS) Michael S. Williamson Texas A&M University-Corpus Christi +1 361-825-2048 HRI 213E Corpus Christi TX 78412 USA michael.williamson@tamucc.edu distributor OPeNDAP DAP/2.0 https://erddap.griidc.org/erddap/tabledap/F2_x836_000_0005_Density_SHELF_FMG_sonar_data.html order Data Subset Form ERDDAP's version of the OPeNDAP .html web page for this dataset. Specify a subset of the dataset and download the data via OPeNDAP or in many different file types. download https://erddap.griidc.org/erddap/tabledap/F2_x836_000_0005_Density_SHELF_FMG_sonar_data.graph order Make-A-Graph Form ERDDAP's Make-A-Graph .html web page for this dataset. Create an image with a map or graph of a subset of the data. mapDigital dataset 2021-09-28T07:51:00Z This record was created from dataset metadata by ERDDAP Version 2.02