Date of Award

1-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Lisa Hazard

Committee Member

John Smallwood

Committee Member

Scott Kight

Abstract

When sunfish (Lepomis spp.) breed, parents defend nest sites and are highly aggressive and territorial against conspecifics and other fish and invertebrate species. However, little is known of their possible effects on sympatric turtle species. In this study I examined the relationship between the musk turtle (Sternotherus odoratus), painted turtle (Chrysemys picta), pumpkinseed sunfish (.Lepomis gibbosus), and bluegill sunfish (Lepomis macrochirus) within Lake Wapalanne, Sandyston, New Jersey. My hypotheses were: presence of musk and painted turtle individuals would diminish within the sunfish nest habitats during the breeding period and would revert back to normal numbers of captures post-sunfish breeding; musk and painted turtles would stay farther away from sunfish nests during the sunfish breeding season; turtles would actively avoid the sunfish nests due to possible negative physical interactions and, if the turtles did enter the nests, the sunfish would defend the nests differently towards each species of turtle due to dissimilar behaviors of musk and painted turtles. To test these hypotheses, I first compared the habitat selection for the sunfish breeding grounds and for the turtles, the relationship between turtle and sunfish nest densities, and the distance of musk and painted turtles to the sunfish nests before, during, and after the sunfish breeding season. All sunfish nests and turtle capture locations were recorded using GPS, and locations were used to make distribution maps and to measure distances of turtles from sunfish nests. Second, I introduced musk and painted turtles into sunfish nest areas and recorded turtle and fish behaviors. My first hypothesis was not supported; there was no significant relationship between turtle densities and sunfish nest densities. Also, painted and musk turtles did not have a higher probability of staying farther away from bluegill and pumpkinseed sunfish nests during the sunfish breeding period. These results could be due to painted and musk turtle breeding behaviors, musk turtle site fidelity, or niche partitioning and passive behavior between the turtles and sunfish. My second hypothesis was also not supported; both turtle species did not avoid the pumpkinseed nests and both turtle species entered a pumpkinseed nest regardless of external variables. However, pumpkinseed sunfish acted differently toward musk and painted turtles once the turtles entered the sunfish nest. The pumpkinseed sunfish had a higher probability of physically encountering and attacking musk than painted turtles. However, no variables could be found to explain these findings and instead it is hypothesized pumpkinseed sunfish could be defending against any predator that spends a long period of time in the nest or attacks a peripheral nest.

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