Graduation Year

2011

Document Type

Thesis

Degree

M.S.E.V.

Degree Granting Department

Geography, Environment and Planning

Major Professor

Joni Downs

Keywords

Bluegill, Habitat, Lepomis, Peace River, Redear, Spotted Sunfish

Abstract

This study examines spatially continuous sampling data in order to investigate patterns of abundance and distribution of three recreationally important sunfish species (bluegill, redear, and spotted sunfish) along the main-stem of the Peace River, a large softwater river located in southwest Florida. A total of 467 electrofishing transects were sampled biannually from spring 2008 to spring 2010. Sampling sites ranged from the headwaters of the Peace River in Polk County, FL to the oligohaline waters located in Charlotte County, FL. All fish were collected with boat mounted electrofishing gear, and aquatic habitat and physiochemical water quality measurements were recorded at each transect. Pearson's correlation coefficient and conical correspondence analysis were used to interpret relationships between sunfish abundance and associated environmental variables. Results showed that relative abundance of sunfish varied significantly between the upper, middle, and lower basins of the river. Distance from headwaters, conductivity and macrophyte coverage were all significant predictors of relative species abundance. Spotted sunfish were found closer to the headwaters and were positively associated with higher amounts of aquatic vegetation. Redear were most common in the middle basin and were most associated with changes in conductivity. Bluegill were relatively more abundant further downriver where conductivities were higher. Woody debris was strongly associated with fish abundance for all species but did not significantly explain the variance in species composition between locations in the river. The result of this study can be used by fisheries professionals to better manage sunfish populations in the Peace River and other lotic systems.