Spotted seatrout, Cynoscion nebulosus, spawning locations as well as associated environmental variables were determined for Tampa Bay, Florida during the 2004 spawning season using a mobile hydrophone survey. Hydrophones, a type of underwater microphone, can be used to detect and record spawning sounds of soniferous fishes. During their spawning season in Tampa Bay which generally occurs between March and September, mature male spotted seatrout generate sounds associated with courtship in the crepuscular and evening periods by vibrating sonic muscles against the swim bladder. Active spawning sites can be located using hydrophones to find these calling males. Using a random stratified sampling method, 760 stations within Tampa Bay (46 % of the sampling universe) were sampled over the 2004 spawning season. Only 8% of sampled stations had large aggregations of spotted seatrout. Spawning, determined by the sound produced by large aggregations, was detected throughout the bay except for Hillsborough Bay and was most common in the lower bay and eastern region of the middle bay. Presence of submerged aquatic vegetation (SAV), proximity to shoreline, as well as high dissolved oxygen values and shallow depth were positively correlated with spawning areas. Courtship calls of sand seatrout, Cynoscion arenarius, and silver perch, Bairdiella chrysoura were also detected during the survey as they share an overlapping spawning season with spotted seatrout. Aggregations of all three species rarely occurred simultaneously. Sand seatrout and silver perch used different habitats within Tampa Bay to spawn and spawned with a much greater frequency than spotted seatrout. Courtship calls of spotted seatrout were analyzed both by ear and by received sound level to determine if signal processing could be used to assess courtship sound recordings. However, there was no clear relationship between the two methods.

Marine ecosystems are highly dynamic and contain a diverse faunal assemblage that are subject to various natural and anthropogenic variability. Globally, seagrass ecosystems are located adjacent to coastal areas that are heavily impacted by human development and urbanization potentially altering the community structure within these ecosystem. Complex food webs connect many components of these systems, often in unexpected ways, and are ultimately based on one of two pathways: benthic (i.e., seagrass, epiphytes, microalgae, detritus) and planktonic (i.e., phytoplankton). Understanding the pathway which the food web is based gives further insight regarding the biological balance of the ecosystem; thus it is important to expand beyond bounds of single-species approaches for research and management. Observing what a predator consumes and its preference for any particular prey can be informative in regards to how a predator interacts and utilizes an ecosystem. Predatory fish are exposed to a wide range of potential prey with varying levels of mobility in their natural environment and may employ a wide range of feeding tactics in order to capture prey. Overall, prey availability and abundances are influenced by many factors (e.g., seasons, tides, habitat loss and gain) and many piscivorous fishes will undergo ontogenetic shift in diet in order to optimize their energetic return limiting the interpretation of electivity studies. Although much information can be obtained through stomach analysis of fish, some prey are more rapidly digested due to the lack of hard, external structures and may be overlooked in the analysis. Furthermore, prey preference cannot be based solely on the observed abundance in the diet of a predator because it takes time for a predator to find, consume, and digest prey (i.e., "handling time"). Therefore, multiple approaches, both observational and experimental, are necessary to fully understand trophodynamics of fishes and their ecosystems. To better understand the trophodynamics of the Spotted Seatrout, Cynoscion nebulosus, my thesis incorporates both an observational and experimental study. My observational study compares three stomach analyses datasets to address changes in the diet composition over a thirty-two year timespan during which natural and anthropogenic changes potentially altered the community structure of Tampa Bay. This is paired with an experimental study to address differently handling times of two morphologically- and behaviorally- different prey that were observed in the diet of juvenile Spotted Seatrout.