Effects of turbidity on foraging and success of age-0 yellow perch (Perca flavescens): Insights from experiments and spatial modeling

Turbidity can affect the foraging of age-0 yellow perch (Perca flavescens) and hence their growth and survival. Laboratory experiments showed that across prey densities, yellow perch tended to consume fewer prey in phytoplankton turbidity compared to sediment turbidity. For larvae, this effect was dependent on turbidity level (consumption differed between turbidity types only at high turbidity), while for juveniles the difference with turbidity type was equal across turbidity levels. These results suggest that phytoplankton blooms are detrimental to the ability of late season age-0 yellow perch to forage, and support the need to control factors leading to excessive phytoplankton growth in lakes.  Modeling of abundance and length-in- August for fish from highly turbid, western Lake Erie using general additive models (GAMs) identified turbidity as the most important environmental factor included.  Turbidity was negatively related to fish length, but positively related to abundance.  Together these laboratory and field results suggest that growth may be slowed due to dense phytoplankton blooms, but turbidity may provide refuge from predation to age-0 fish.