Short-term upwelling events modulate fish sound production at a mid-Atlantic Ocean observatory

Understanding factors controlling the distribution and reproduction of fishes is crucial for developing ecosystem models of fish populations. Yet, these observations are difficult to make on the same time and space scales as physical forcing events. A hydrophone was used to record fish sound production associated with reproduction at the LEO-1.5 ocean observatory to determine the relationship between variation in fish calling behavior and oceanographic variation. Sound production was dominated by Atlantic croaker Micropogonias undulatus, weakfish Cynoscion regalis, and striped cusk-eel Ophidion marginatum. Striped cusk-eels called with a crepuscular pattern, with a strong peak at dusk, less sound production during the night, and a lesser peak in sound production at dawn. Sciaenids called mostly at dusk and night. Nine advection events bringing colder waters to the LEO-15 site were correlated with greatly reduced levels of sound production in Atlantic croaker and weakfish on daily time scales. Our results show how ocean observatories with passive acoustics can study tightly coupled physical oceanographic influences on fish behavior on daily time scales.