Developing an Approach for Interagency PIT Tag Mark-Recapture Surveys of Lake Erie Yellow Perch

Originally, quota management units for Lake Erie yellow perch were to be based on lakewide tagging studies, but these conventional tagging studies were plagued by the inability to determine the number of tags-at-large due to tag loss, high non-reporting rates, and acute mortality from handling and barotrauma. More recent PIT tag technologies alleviate tag loss and non-reporting rates, but evaluation of the adequacy of current tagging and catch scanning efforts has been limited by a lack of understanding of acute mortality. We used caging studies to develop estimates of acute mortality and iteratively improve survival in PIT tagged Yellow Perch captured by trawls and trap nets.   We tagged 6,889 yellow perch at three locations in Lake Erie using trawls (4-19m) and trap nets (9m). Trawls had higher handling mortality (35%) compared to trap nets (2%), and barotrauma similarly affected both methods when controlling for depth.  Shallow trap net tagging (6m) alleviated barotrauma, and resulted in the highest acute survival estimates based upon caging experiments.  These experiments support more accurate accounting of the number of tags at large, which in turn facilitates evaluation of the scanning effort and development of exploitation estimates.