Relationship between Population Density, Individual Fitness, and Blackspot Infections in the Yellow Perch Perca flavescens

Elaine (Yiling) Luo


Population density, disease, and individual fitness are central themes in the study of population ecology. However, the fitness costs of increased population density and blackspot parasitism remain unclear. This study addresses the effects of population density and parasitism on the fitness of the yellow perch Perca flavescens. Fifteen populations of yellow perch were examined for blackspots, a common parasitic nematode, measured, weighed in Lake Opeongo, Algonquin National Park. Blackspot parasitic load did not appear to correlate with either population density or with fitness, while fitness was correlated with population density. These findings suggest that rather than directly through blackspot parasitism, individual fitness appears to be influenced by factors associated with increased population density. Our correlational study elucidates the relationship between these three population parameters and explores other mechanisms to which parasitism can influence the fitness of juvenile P. flavescens.

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© University of Toronto Journal of Undergraduate Life Sciences.