Tailwater Trout Population Dynamics

Dams have been constructed throughout the world and provide several resources for humans (e.g., flood control, hydropower). These structures heavily alter the upstream and downstream environment. One consequence of these alterations is the creation of “tailwaters”, which can create cold-water habitat via hypolimnetic releases. In the southeast United States these tailwater environments are often managed for the recreational use of nonnative salmonids. The unnatural flow regimes of tailwaters affect the biotic and abiotic conditions and ultimately the dynamic rate functions (i.e., recruitment, growth, mortality) of the fish inhabiting them. As such, the goal of this research is to provide fisheries managers with tools to accurately assess these populations while accounting for the unique challenges tailwaters present. The effects of different hook types on the mortality of rainbow trout (Oncorhynchus mykiss) in two tailwaters in Arkansas were investigated. Hook type had little effect on mortality, but rather hooking location was the main determinant of mortality. Additionally, potential negative and unaccounted for mortality that may occur from hooking mortality was calculated. Next, a standard weight equation (Ws) and standard-length categories for tailwater brown trout (Salmo trutta) were developed using length-weight data from 12 tailwaters across the Southeast United States. These standards were then compared against existing standards for brown trout in non-tailwater environments. This research adds to the existing body of literature and provides fisheries managers with more accurate tools to describe their populations.