Spatiotemporal Variation in Abundance and Social Structure of Bottlenose Dolphins in the Florida Coastal Everglades

Ecological niche partitioning within a large predator guild in a nutrient‐limited estuary

“…Indeed, habitat use and activity rates are often driven by environmental conditions. Within the Shark River Estuary, seasonal movements of alligators and snook attributed at least partly to reproduction (Rosenblatt and Heithaus ; Andrade et al ; Lowerre‐Barbieri et al ), salinity tolerance of alligators (Rosenblatt and Heithaus ; Rosenblatt et al ), and apparent seasonal movement patterns of dolphins and tarpon (Luo et al ; Sarabia ) appear to reduce overlap, which may promote coexistence among predators (e.g., Rosenblatt and Heithaus ; Trotter et al ; Matich and Heithaus ).…”

“…) consists of a series of shallow bays and deeper channels lined by mangroves, which provide habitat for a variety of freshwater, estuarine, and marine taxa. Many predators, including crocodilians, elasmobranchs, teleost fishes, and marine mammals use the extent of the estuary seasonally or throughout the year for at least part of their life history, with some seasonal shifts in distribution attributed to temporal fluctuations in water temperature and salinity (e.g., Sarabia ; Boucek and Rehage ; Rosenblatt et al ; Fujisaki et al ). Productivity varies spatially and temporally throughout the estuary, with outwelling and nutrient limitations upstream leading to higher levels of productivity in marine habitats (Childers ; Simard et al ).…”

“…Common bottlenose dolphins are abundant predators throughout the coastal Everglades, with higher densities found in coastal waters and inland bays than in river systems, including the Shark River (Sarabia ). However, use of rivers increases during the dry season (typically January to June), while densities in other habitats remain similar across seasons (Sarabia ). Sixteen bottlenose dolphin sighting and biopsy surveys were conducted within the Shark River Estuary across all study areas from August 2010 to September 2013 at 15 km/h in Beaufort wind conditions three or less.…”

“…Sixteen bottlenose dolphin sighting and biopsy surveys were conducted within the Shark River Estuary across all study areas from August 2010 to September 2013 at 15 km/h in Beaufort wind conditions three or less. Sighting data during dry and wet seasons was used to estimate dolphin distribution within the greater estuarine area of the southern Shark River Slough (including Joe River, Ponce de Leon Bay, and Whitewater Bay; see Sarabia ), and within the spatial scope of the array of acoustic receivers. When dolphins were encountered, standard group data were recorded, including geographic position and group characteristics (e.g., group size, presence, and number of neonates and calves).…”

Survival of Florida Largemouth Bass in a Coastal Refuge Habitat across Years of Varying Drying Severity

“…Concentrated Florida Largemouth Bass in the upper SRE may experience predation from marine and freshwater predators that take advantage of prey pulses accompanying marsh drying. This includes Bull Sharks Carcharhinus leucas (Matich and Heithaus 2014), American alligators Alligator mississippiensis (Rosenblatt and Heithaus 2011), bottlenose dolphins Tursiops truncatus (Sarabia 2012), and intraguild predators such as Common Snook Centropomus undecimalis (Boucek and Rehage 2013). In addition to predation, the concentration of fish in coastal refuges also increases their susceptibility to fishing pressure (Boucek and Rehage 2015), potentially leading to both higher catch-and-release and harvest mortality (Kerns et al 2012), although CAST participants reported very low harvest numbers.…”