Connecting fish to the landscape: Land use and climate change effects on yellow perch growth in western Lake Erie

Background/Question/Methods

The effects of increasing urbanization and global climate change are not limited to the terrestrial environment. Alterations in sediment and nutrient transport from a watershed can result in substantial reductions in water clarity through sediment plumes and algal blooms. These plumes and blooms have the potential to alter the growth, and ultimately the recruitment, of visually foraging fish species, such as the yellow perch (Perca flavescens). In this study we use a Soil and Water Assessment Tool (SWAT) and Individual Based Model (IBM) to link changes in land use and climate in the Maumee River watershed to the yellow perch fishery in the Maumee Bay of western Lake Erie. In doing so, we address two specific questions: 1) What are the potential effects on the growth of age-0 yellow perch in the Maumee Bay due to current and possible land use practices in the Maumee River watershed, and 2) What are the potential impacts on age-0 yellow perch growth due to changes in the watershed based on predicted changes of the regional climate?

Results/Conclusions

The results of our land use models show that increasing urbanization can lead to a significant reduction in yellow perch growth by altering the timing and intensity of sediment plumes. However, this effect is only seen at very high levels of urbanization, likely due to the influence of non-point source agricultural runoff in the Maumee basin. The predicted changes in regional climate have the potential to reduce age-0 yellow perch growth by up to 10%.  The reduction in growth is the result of increased water temperatures that cause an earlier onset, and longer duration of algal blooms in the Maumee Bay. Our results show that alterations to land use and climate in a watershed have the potential to significantly alter the growth of a visually foraging fish species by altering the timing and intensity of downstream sediment plumes and algal blooms.