Assessing the Effects of Habitat and Manatee Exclusion Devices on Red Drum (Sciaenops ocellatus) Movement Patterns in Estuarine Impoundments

• Main Author: Baker, Steven
• Format: Text
• Language: English
• Published: University of Central Florida 2019
• Subjects: Biology; Terrestrial and Aquatic Ecology; Red drum; Sciaenops ocellatus
• Online Access: https://stars.library.ucf.edu/etd/6835; https://stars.library.ucf.edu/cgi/viewcontent.cgi?article=7835&context=etd

The Integrate-Transfer-Launch (ITL) complex impoundments located within the Kennedy Space Center security zone are known spawning sites for red drum (Sciaenops ocellatus). However, recent construction of manatee exclusion bollards around culverts leading into these impoundments may impede movement to and from this critical habitat. The goals of this study were to: 1) utilize passive acoustic telemetry to document patterns of red drum movement and habitat use within and around the ITL impoundments to assess how manatee exclusion bollards and environmental conditions may impact movement of red drum; and 2) explore red drum movement in response to environmental disturbance, specifically a severe hypoxia-induced fish kill event. Manatee exclusion devices were shown to impede the movement of relatively large red drum with head widths greater than the mean distance between bollards of 16.0 (± 3.4) cm. Additionally, the growth of biofouling organisms further reduced the spacing between bollards by an additional 0.5 (± 0.3) cm per month and thus impacted the movement of a greater size range of fish from moving successfully through the barriers. Red drum home range area and daily distance traveled were related to dissolved oxygen concentrations within the water. As dissolved oxygen levels decreased within the ITL impoundments, fish habitat use area also decreased. Episodic exposure to hypoxic conditions caused increased daily movement for fish, increasing from 2745.3 (± 1721.3) m during normoxic conditions to 3304.7 (± 1154.3) m in periods of hypoxia. However, during prolonged exposure to anoxic waters, fish distance and rate of movement was significantly reduced (normoxic: 2572.1 (± 1105.5) m / 2.5 (± 0.9) m/s; anoxic: 714.9 (± 395.4) m / 2.1 (± 1.1) m/s). The results of this study suggest manatee exclusion devices act as barriers to fish movement and decrease habitat connectivity; using this knowledge ecosystem-based management strategies are recommended that simultaneously benefit sportfish and marine mammals inhabiting Florida's estuaries.