Understanding when, where, and why animals move is a central theme in ecology, and the timing and scale of movement can carry consequences ranging from the growth and survival of individuals to the flow of energy through ecosystems. However, gaps remain in quantitative research that links movements with environmental drivers, and that describes how key prey subsidies affect the fitness of consumers. My dissertation examined the movements of the ecologically and economically important fish species Common Snook (Centropomus undecimalis) in the Shark River (SR), Everglades National Park (ENP). I used eight years of acoustic telemetry data (AT) coupled with long-term community sampling data to quantify how movement patterns and foraging relate to seasonal/interannual environmental variation. First, I quantified seasonal/annual patterns in freshwater-to-coast spawning migrations using AT and related these movements to hypothesized drivers using generalized linear mixed models (GLMMs). Results showed both interannual and seasonal variation. The number of fish migrating ix each year was best explained by seasonal drops in water level and fish size, and the timing of migration was most correlated with water level and daily rates of change. Next, I used AT to investigate how extreme disturbance influenced movements during Hurricane Irma using generalized linear models to relate movements to hypothesized drivers representing riverine/hurricane conditions. During Hurricane Irma, 73% of tagged fish made downstream movements, and movement responses were best explained by a combination of water level and barometric pressure. I then used long-term electrofishing data to examine how the magnitude of a seasonal prey subsidy (sunfishes, Lepomis spp.) and seasonal/interannual environmental variation affect the body condition of Snook using GLMMs. Results showed wide year-to-year variation, with body condition increasing with higher prey biomass, lower water levels, during the wet/dry transition, and with fish size. Finally, I used time-series data of environmental conditions in the SR to examine long-term trends in environmental change and related these trends to the relative abundance of Snook over time. This research can extend beyond Snook in ENP and can help inform how other species may respond to climate change and water management in impact-prone coastal regions.
