Differential acoustic habitat use in delphinids along the Florida Atlantic coast

Acoustic signaling is fundamental to dolphin ecology, with echolocation primarily supporting foraging, navigation, and predator avoidance, and whistles facilitating social communication. Here we investigate potential acoustic habitat differentiation in oceanic dolphins (delphinids) along the Florida Atlantic coast by identifying distinct environmental conditions associated with each signal type and investigating their relationships with soniferous fish presence. Delphinid acoustic signals were recorded during a two-month deployment of a wave glider equipped with a Remora-ST acoustic recorder. Additionally, environmental variables including sound pressure level (SPL), anthropogenic noise, soniferous fish presence, location, temperature, current speed and direction, depth, distance to the coast, salinity, and chlorophyll-a concentration were recorded. Generalized additive models (GAMs) were used to identify key predictors of whistle and echolocation occurrence, and best fit models were then used to generate predictive maps of suitable habitat for each signal type and for soniferous fish. Our results revealed unique environmental predictors of delphinid presence, depending on acoustic signal type (echolocation vs whistles) and distinctly different areas of high detection, which was further reflected in predicted habitat suitability. Furthermore, the presence of soniferous fish is shown to influence acoustic vocalization type and detection, offering an initial look into potential predator-prey interactions shaping delphinid vocalization behavior. This research offers valuable insight for management, particularly in identifying key foraging grounds and social hotspots and further validates the capabilities of passive acoustic monitoring via wave gliders for ecological insights of cetaceans.