Changes in fish sound production in the northern Gulf of Mexico over six years

Abstract

Passive acoustics were used to evaluate changes in the presence of soniferous fishes in the northern Gulf of Mexico. Recordings were collected at a site on the continental shelf at 90 m depth, approximately 40 miles east of the Mississippi river delta, from July 2010 through 2016. Seven distinct sounds were detected in 2010 during the first recordings. The occurrence of these sounds over subsequent years was analyzed using automatic detection and classification methods based on convolutional neural networks. Croaks (likely produced by the Atlantic croaker, Micropogonias undulatus) and “jet-ski” calls (likely produced by the Atlantic midshipman, Porichthys plectrodon) were among the most common in 2010 with unique diel patterns. The monthly patterns of calling changed over the six years, likely indicating a change in the fish community structure at this site across the years. Factors that could explain this change include interannual variability due to the extent of anoxic zones, variability in ocean temperature, circulation, or possible impact of the oil spill on fishes in the area. Further investigation on the behavioral context of these sounds would provide insight into likely consequences of the change in calling to these soniferous fishes.