Passive acoustic monitoring can be a useful tool to include on Ocean Observing Systems. As an example, we describe the monitoring the acoustic environment in the coastal waters of North Carolina (USA) using an instrumented platform. The ECU Itpod (instrumented tripod) has been deployed in several locations in Pamlico Sound and river estuaries since 2006 to study fishes in the Family Sciaenidae (drums and croakers). We will present data recorded with hydrophones deployed on the Itpod with remote data loggers, acoustic Doppler current profilers, turbidity meters and water quality instruments. We have used passive acoustic recordings to study the correlations of fish sounds and environmental parameters (temperature, salinity, turbidity, dissolved oxygen, wave action, river discharge, tropical storms). The long-term data suggest that spring temperature increases are associated with increased activity of acoustically mediated courtship and spawning behavior of sciaenid fishes; these sounds decline in the fall as water temperature declines. In addition, we have observed acoustic interactions between marine mammal predators and their fish prey and the effects of noise from tugs and small boats on fish sound production. Itpods must be recovered periodically to recover data and replenish batteries; solar-powered platforms and automated fish detection algorithms are under development.