ABSTRACT
Despite the lack of site-specific data for some parameters (e.g., fecundity), the population model developed herein provides reasonable guidance as to which populations would most likely increase if entrainment and impingement losses were to be removed. To reduce the possibility of inappropriate decisions being made, a conservative approach was taken at each decision point in compiling the model. Until the model can be refined using additional site-specific data, interpretation of the model outputs should be done cautiously and should not focus on the absolute values for average expected change for a given species and pool. Rather, the focus should be on relative differences among species and pools in the values for average expected change. The resolving power of the model is currently limited by the lack of site-specific age/growth and fecundity data, as well as the inability of electrofishing to capture all age (size) classes equally. Even though an adjustment was made for electrofishing size-dependent efficiency, other unquantifiable factors undoubtedly also affect electrofishing results. For example, larger individuals of species such as sauger and freshwater drum are less shoreline oriented than the smaller individuals of these same species. Thus, the apparent absence of large sauger and freshwater drum in the electrofishing database is likely an artifact associated with the behavioral characteristics of these species. Examination of ORSANCO lock chamber rotenone data for sauger and channel catfish confirmed that larger individuals of these species were more abundant than the electrofishing data suggested[22].
