Perhaps the biggest problems affecting aquatic ecosystems today is increasing sediment loads. In these projects, we are examining the effects of turbidity on: reactive distance, capture success and ultimately optimal habitat use by several water-column fishes (rosyside dace Clinostomus funduloides, river chub Nocomis micropogon, bluehead chub Nocomis leptocephalus), and will probably conduct future studies on an invasive species (yellowfin shiner, Notropis lutipinnis) and blackbanded darter (Percina nigrofasciata). We would like to use these data to build a model that will predict population-level effects of turbidity changes on these species. Experiments are being conducted in our artificial stream systems at UGA and in the laboratory of Mark Fairbrass at Georgia Military College. Funding for this project comes from NSF, EPA and the Warnell School of Forestry and Natural Resources. An example of a river chub foraging in clear water, one prey is released every minute, four captures are shown. These mpegs are three minutes long and take a while to download, I would only attempt it if you have a high-speed connection (DSL, cable, T1, etc.) Here, a river chub is foraging in water with low turbidity, notice the difference in position of the fish (it holds at the front of the tank) and how prey are captured (the fish turns and captures prey that have passed, rather than capturing them from straight ahead).

To view more research activities by Dr. Gary Grossman, visit his research page