Abstract:

This dataset includes time/date=stamped, geo-referenced raw counts, and corresponding density estimates, of reef fishes along randomly selected transects throughout the northern Gulf of Mexico within 30 to 200 meters of water. These counts are based on video footage collected using the towed video camera system, C-BASS. The transects mainly focused on pipeline infrastructure but also sampled unconsolidated mineral substrates (sand/mud) and select hardbottom areas. A total of 6 cameras (four forward-facing, two side-facing) were recording but fish data analyses were only performed on the video from the highest-quality, forward-facing camera. CMECS-based habitat analyses were also performed in 15-second intervals for corresponding, detailed bottom characterization to supplement the fish counts/density.

Suggested Citation:

Grasty, Sarah and Abigail Vivlamore. 2021. Towed video (C-BASS) based density estimates for reef fishes between 30-200 m of depth along pipelines, on unconsolidated substrates (mud/sand), and hard bottom structures throughout the Gulf of Mexico 2018-04-27 to 2020-01-16. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-s7n8-df25

Purpose:

Data were collected as part of the Great Red Snapper Count to cover the pipeline infrastructure and unconsolidated bottom strata along the northern Gulf of Mexico. Some limited work was done over natural hardbottom, as well.

Data Parameters and Units:

Dataset contains one excel file with the following tabs: Red Snapper HM Master Sheet; Red Snapper PL Master Sheet; Red Snapper MUD Master Sheet. The headers are SITE; DATE (m/dd/yyyy); CBASS_lon; CBASS_lat; Survey_Method; Structure Type; Habitat_Score; Area Surveyed (sq-m); Red Snapper Count; Red Snapper Density (per100sqm); Linear m sampled; Red Snapper per linear m; PL Diameter; Survey Area. PL = Pipeline; MUD = Unconsolidated Bottom; HB = Natural Hard Bottom

Methods:

Field-of-view for counts to density conversion is calculated using inherent camera/lens FOV underwater (59.2 deg), altitude of the system, angle of the camera relative to horizontal, and pitch of the system. Image processing was done manually by a technician using CVision AI's annotation program, tator (https://github.com/cvisionai/tator). Original video is located on GRIID-C under dataset title "Towed video (C-BASS) collected between 30-200 m of depth along Pipelines, on Unconsolidated Substrates (mud/sand), and Hard Bottom Structures in the U.S. Gulf of Mexico." The system was flown at a typical altitude of 3-5 meters above bottom but more detailed information on altitude can be found in the Field-of-View (FOV) tab within each workbook. Timestamps and dates are in UTC.

Instruments:

The Camera-Based Assessment Survey System (C-BASS), the University of South Florida - College of Marine Science's custom towed camera system.

Individual Files: