Habitat Partitioning and Seasonal Movement of Red Drum and Spotted Seatrout
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2016, Coastal and Estuarine Research Federation. Acoustic telemetry was used to examine habitat use and movement of two sympatric gamefishes, red drum (Sciaenops ocellatus) and spotted seatrout (Cynoscion nebulosus), at two spatial scales (habitat and bay) within an estuarine complex. Habitat-scale tracking (~ 1m1km) based on an acoustic positioning system revealed that seagrass was used extensively by both species. Red drum also commonly associated with oyster reef and boundaries between habitat types. Spatial overlap between the two species was limited and indicative of habitat partitioning; red drum were commonly observed in the shallow, inner lagoon and spotted seatrout in the deeper, open bay portion of the array. Conspicuous diel shifts were also observed for spotted seatrout; fish transitioned from seagrass to bare substrate and displayed greater rates of movement at night than day. Bay-scale (150+ km) tracking over a two-year period primarily showed limited movement within bays; however, directed bay-scale movements by both species were observed during winter and spring, when a small contingent of individuals moved up to 70km from original tagging locations. Habitat use and movement were species specific and subject to temporal variation, both diel and seasonal. Habitat-scale connectivity was influenced by seascape structure and water depth, and bay-scale connectivity was generally limited, suggesting the sustainability of these fisheries is likely influenced by local conditions.