Red Drum (Sciaenops ocellatus) Interactions with Vessel Noise in the Northern Gulf of Mexico

Red drum (Sciaenops ocellatus), a vocal fish species found in waters along North America’s East Coast and northern Gulf of Mexico, forms large, vocal spawning aggregations in near-shore waters. These in-shore regions also experience frequent vessel traffic, both commercial and recreational, and resulting noise pollution is predicted to negatively impact sound-producing fishes. Noise pollution can increase hearing thresholds, damage sensory epithelia, and alter behavior. The aim of this research was to determine how often red drum calls are masked and how they respond via sound production. During 2021–2022, vessel noise and fish sounds were obtained via passive acoustic recorders in Saint Andrews Bay, Panama City Beach, Florida. Presented here are preliminary analyses of October 2021. Red drum sounds occurred frequently at this site during spawning season (June–November). Red Drum calling peaks immediately after sunset and significant overlap was found between chorusing and vessel noise during this calling period. The contribution of call pulse number, vessel noise, and sound pressure was tested. Preliminary results indicate red drum decreases call rate when intense boat noise occurs, and calls are masked. This suspected behavior modification and subsequent call masking could decrease spawning success and impact fitness. Ongoing analyses of 2021–2022 spawning seasons will address these questions further.