Abstract:

Four hydrophones were installed at the Florida Middle Grounds (FMG). Recordings were made from 2017-04-25 to 2017-06-11 to identify sound-producing fish species in the FMG area and to monitor diel and lunar variations in their sound production. Acoustic digital spectrum recorders were deployed at four locations in the FMG on 2017-04-25. The bottom depth at the study sites ranged between 35 and 40 m with 10-15 meters of vertical relief. Hydrophones were programmed to record ten seconds of sound every five minutes at a 50 kHz sample rate. The 51 days of processed data from three of the sites are included here. The data consist of the mean sound pressure levels in dB (relative to 1 micro pascal) in 100 Hz or 300 Hz bands between 100 and 1200 Hz. Active-acoustic transects and fish density and habitat classification, also part of this experiment, are found in related datasets under GRIIDC Unique Dataset Identifiers (UDIs): F2.x836.000:0005 (https://doi.org/10.7266/n7-axjv-t334) and F2.x836.000:0007 (https://doi.org/10.7266/n7-n5p5-c621).

Suggested Citation:

Locascio, James. 2021. Hydrophone recordings on Florida Middle Grounds from 2017-04-25 to 2017-06-11. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-8r9q-8f26

Purpose:

Hydrophones were recorded to monitor spawning activity prior to, during, and after egg collections.

Data Parameters and Units:

Shelf Florida Middle Ground Site #; Latitude [Degrees Decimal Minutes, North]; Longitude [Degree Decimal Minutes, West]; Date [M/DD/YYYY]; Time [HH:SS]; mean sound pressure level [relative to 1 micro pascal, (dB)] for 0-100 Hz,100-200 Hz, 200-300 Hz, 300-400 Hz, 400-500 Hz, 500-800 Hz, 800-1200 Hz.

Methods:

The locations were selected from georeferenced multi-beam images of bottom topography that identified high-relief promontories, a habitat feature generally associated with high fish density and fish reproductive behavior. The hydrophones were moored by divers to steel rebar anchored in the limestone substrate and remained stationary approximately 1 m above the seafloor for the duration of the deployment. Each 10-second acoustic file was analyzed in MATLAB, version R2009b, with a 1024-point Fast Fourier Transform to generate a power spectrum from which the band decibel (dB) sound pressure level (SPL) in 100- or 300-Hz-wide bins was calculated. Patterns in fish sound production were examined in plots of power spectra for diel, seasonal, and lunar periodicities (not included in this dataset). Spectrograms of acoustic recordings were reviewed with Adobe Audition, version 2.0 (Adobe Systems Inc., San Jose, CA) to identify which species were present in the recordings, to the extent possible, and describe any previously undescribed calls.

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