Date of Award

Spring 2008

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

Robert F. Young

Second Advisor

Wendy R. Hood

Third Advisor

Kevin S. Godwin

Additional Advisors

Richard H. Moore;Geoffrey E. Hill

Abstract

Bluegill sunfish are known for their bright yellow to red breast coloration which is described as being brighter in nest-building males and becoming brighter still with the onset of breeding. Carotenoid pigments have been isolated from the integument of bluegills but have not been verified as the source of coloration. As bluegills also incorporate algal and plant material into the diet it has been suggested this behavior may serve to augment pigmentary displays. The goals of this research were to determine whether bluegills display carotenoid breast coloration, to ascertain if variation in color between male and female bluegills is due to differences in carotenoid display, and to investigate correlations between breast color display and algal consumption. Bluegills were collected weekly throughout the summer of 2006 from a farm pond in Horry County, SC. Breast color was measured in the field using reflectance spectrometry. Stomach contents were analyzed in the lab. This research confirms carotenoids as the source of coloration in the breast region of bluegills and quantifies previously subjective descriptions of color. Male bluegills in this population have higher chroma than females. No differences were discerned in algal consumption between males and females, perhaps owing to the lateness of the breeding season in which specimens were collected. Conversely, larger male bluegills, most likely representing parental males, incorporated more algal material into the diet and had lower brightness than smaller males, presumed cuckolding sneaker and satellite males.

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