Doctor of Philosophy (PhD)
Oceanography and Coastal Sciences
Spotted seatrout (Cynoscion nebulosus) is one of the most highly prized sportfish along the Gulf of Mexico coast, particularly in Louisiana. Although spotted seatrout are considered to be well managed and sustainably fished according to the state’s most recent stock assessment, the spatial ecology of this species is largely understudied in Louisiana waters. Acoustic telemetry is an innovative technology that is commonly used to assess the movements and behavior of aquatic species, and can be used as a tool to address the paucity of information on the spatial dynamics of spotted seatrout. The focus of this study was to describe the movement and distribution patterns of spotted seatrout within Lake Pontchartrain by utilizing remote acoustic telemetric methods aimed at addressing three primary objectives: 1) determine the detection efficiency of stationary acoustic receivers and their ability to accurately estimate emigration rates of spotted seatrout through extensive range testing within the lake proper and tidal passes, 2) investigate the influence of biotic and abiotic characteristics on habitat utilization of spotted seatrout in a dynamic environment, and 3) examine movement and survival rates of spotted seatrout in Lake Pontchartrain with respect to both seasonal and regional variability. A total of four acoustic receivers and two fixed delay tags were deployed for 365 days to evaluate how the detection range varied through time and under different environmental conditions. Whereas distance, time deployed, and transmitter type substantially influenced performance of the telemetry array deployed in Lake Pontchartrain, temperature, turbidity, and northerly wind velocity were also significant factors in the reduction of detection range. From November 2012 to November 2014, the movements of 211 spotted seatrout were monitored with a basin-wide acoustic array composed of 90 autonomous receivers. Results indicated that temperature and salinity were strong environmental drivers affecting the seasonal distribution and migration patterns of tagged spotted seatrout. Acoustic data were used to estimate survival and total instantaneous mortality under a multistate mark-recapture framework. Mark-recapture model estimates indicate that monthly survival ranged from 5% to 92%. Estimates of annual loss (A) were higher than values reported for spotted seatrout across the Gulf of Mexico region.
Baer, Ashley Melancon, "Population Dynamics and Demographics of Spotted Seatrout, Cynoscion nebulosus, Through Spatial Analysis: Towards an Integrative Management Approach" (2019). LSU Doctoral Dissertations. 4831.
Cowan, James H. Jr.