Relationships between condition factors, parasite load and paternity in bluegill sunfish, Lepomis macrochirus

We examined the relationship between non-polar lipid density, parasite density and paternity of male bluegill sunfish, Lepomis macrochirus, and four condition factors: (1) Fulton’s condition factor, K; (2) the relative condition factor, Kn; (3) the relative mass index, Wr; and (4) the residuals from the geometric regression of mass on total length, C. Although the four factors were highly correlated to each other, only K and Wr were significantly correlated with non-polar lipid density, explaining about 40% and 25% of the variation, respectively. K was also the best predictor of parasite density and was significantly correlated with the paternity of nesting males. These data provide support for K as a good indicator of individual energetic state and overall quality during the breeding period and demonstrate the importance of energetic state for understanding reproductive success in bluegill sunfish.