An Individual Based Model of Larval Yellow Perch to Link Behavioral Effects of Methylmercury to Adverse Population Outcomes

Historically, yellow perch were highly abundant throughout the shallow areas of Lake Michigan; however their populations have experienced a decline since the early 1990’s.  The poor recruitment has been associated with changes in trophic structure and adverse environmental conditions, however the possible effects of contaminants have not been explored fully. Methylmercury (MeHg), a persistent contaminant found in the Great Lakes, has been shown to alter foraging and predator avoidance behaviors of larval yellow perch and these behaviors could affect overall growth and survival. We adapted an individual based model (IBM) to incorporate laboratory derived MeHg effects on a larval yellow perch cohort. We also calibrated the IBM to simulate real-life situations in Lake Michigan and nearby Crystal Lake, and varied community structures to accommodate multiple stressor scenarios. Our model simulations suggest that exposure to neurotoxic contaminants such as MeHg, when coupled with low food availability and suboptimal water temperatures, could potentially significantly reduce cohort survival. Our findings on the effects of MeHg on recruitment suggest that contaminants could be another factor that could impact recruitment of larval yellow perch in Lake Michigan, and that this deserves further exploration.