Use of Individual Based Models to Explore the Effects of Turbidity on Growth and Survival of Age-0 Yellow Perch

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Turbidity is an environmental factor that affects the foraging, growth, and survival of age-0 fish.  Many coastal ecosystems are affected by high turbidity, especially areas that receive discharge from large rivers, which provide a major source of suspended solids and nutrients. Laboratory experiments show reduced larval feeding rates of age-0 yellow perch with increasing phytoplankton turbidity and a significantly lower juvenile feeding rate with phytoplankton and sediment -derived turbidity. We parameterized an individual based model with laboratory and literature values to determine how turbidity intensity and type influence larval yellow perch growth and survival through the first 120 days post-hatch.  Our model showed increased larval growth in those exposed to high sediment turbidity and drastically reducing growth in larvae and juveniles exposed to high algal turbidity. We compared our results to historical data from western Lake Erie and found a good relationship for size-at-age (R² = 0.72, p < 0.001) while only a weak relationship to cohort size (R² = 0.02, p=0.076).  Our results suggest high levels of turbidity can provide a reduction in predation mortality by hindering visually foraging predators’ ability to successfully detect and capture larvae, however this reduction is offset by an increase in starvation mortality in juveniles exposed to high sediment turbidity.