USGS scientists and partners used estimates of river and streamflow and observed fish abundances to develop tools that specify the response of fish to alterations in those flows. They fit the logistic model to a cumulative fish abundance curve as a function of yield providing an empirical means to develop models of the response of cumulative fish abundance to flows. Response zones of yield for each species in each system type illustrate how criteria may be developed that can be used in decision-making for management of flows. Mapping stream sensitivity to flow alteration throughout the Great Lakes Region with a multiscale spatial framework showed how regional variability in sensitivity for any fish species or assemblage may be evaluated and provides managers with information to help determine where the best opportunities for protection or restoration of streamflows and associated communities exist.
