Document Type

Thesis

Degree

Master of Science (MS)

Department

Biology

First Advisor's Name

Joel Trexler

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Mike Heithaus

Third Advisor's Name

Kevin Boswell

Keywords

Everglades, canals, fish, predation, acoustics

Date of Defense

11-2-2012

Abstract

Landscape characteristics, disturbances, and temporal variability influence predator-prey relationships, but are often overlooked in experimental studies. In the Everglades, seasonal disturbances force the spatial overlap of predators and prey, potentially increasing predation risk for prey. This study examined seasonal and diel patterns of fish use of canals and assessed predation risk for small fishes using an encounter rate model. I deployed an imaging sonar in Everglades canals to quantify density and swimming speeds of fishes, and detect anti-predator behaviors by small fishes. Generally, seasonal declines of marsh water-levels increased the density of large fishes in canals. Densities of small and large fishes were positively correlated and, as small-fish density increased, schooling frequency also increased. At night, schools disbanded and small fishes were observed congregating along the canal edge. The encounter rate model predicted highest predator-prey encounters during the day, but access to cover may reduce predation risk for small fishes.

Identifier

FI12120504

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