Scuds are widely distributed and common in unpolluted clear waters. They are found in vegetation or hidden under and between debris and stones near the banks of the water. The species of scuds I found in the Lower Eau Claire Watershed is the Gammarus fasciatus. According to the Fresh-Water Invertebrates of The United States, 3rd Edition, by Robert W. Pennak, very little is known about the passive transport of the amphipods from one drainage system to another.