Milligan, Scott, Department of Earth and Environmental Science, Susquehanna University, 514 University Avenue, Selinsgrove, PA 17870, milligan@susqu.edu; Ashcraft, Sara A., Freshwater Research Institute, Susquehanna University, 514 University Avenue, Selinsgrove, PA 17870.
Invasive species have caused multiple large scale ecological issues, including the extinction of many species. These invasive organisms directly affect native species by ways of outcompeting them or forcing them outside of their ecological niche. Understanding these relationships can be key in attempting to slow the spread of these invasive species. In the Susquehanna River Basin, native tessellated darters and invasive banded darters have similar substrate preferences as they both tend to prefer larger substrate sizes. It is believed that banded darters entered the Susquehanna in the late 1960s from the Ohio River Basin via a bait bucket transfer and since then have become the most abundant darter species in the Susquehanna (Gray and Stauffer, 2001). Banded darters are larger and much more aggressive than their tessellated counterparts, which is likely affecting the natural behaviours. To investigate this, I will use a mock stream channel system at Susquehanna University’s Freshwater Research Institute. This system has four independent 10 ft. x 2 ft x 2 ft. channels that are split into three sections. Each section will have two fish in three pair combinations: tessellated and tessellated, banded and banded, and tessellated and banded, and have four substrate sizes available, with preference of substrate size observed over a two hour trial. I hypothesize that both tessellated and banded darters will each prefer the larger substrate sizes when they are separated, however when placed together the aggressive behavior of the banded darters will force the tessellated darters away from the substrate that they prefer and to the smaller substrate sizes.
Invasive Species, Tessellated Darter, Banded Darter, Substrate