Heterosporosis a disease caused by a microsporidian parasite, Heterosporis sutherlandae, and can result in lesions in the host muscle tissue. I developed a stochastic, cohort-based integrated disease model to predict the impacts of this parasite on a yellow perch (Perca flavescens) population. I addressed if heterosporosis can cause large losses of yield and which factors are most important to yield. I conducted field and laboratory work to parameterize my model. I found that heterosporosis was rare in all field sites and sampling seasons (6% average prevalence). Transmission by feeding infected tissue ranged between 23% and 31%, while only 2% of minnows exposed by near direct contact became infected. My model indicates that heterosporosis may become extinct in Leech Lake in 25 years, is unlikely to cause significant losses of yield, and that yield is more sensitive to bioenergetic parameters (183% change in yield) than to disease (<1% change in yield).
