Distribution and Speed of Migration for Upstream Migrating American Eels Tagged at the Beauharnois Power Dam and Recaptured at the Moses-Saunders Power Dam

A total of 8,610 juvenile American eels were tagged with passive integrated transponders at the Beauharnois Power Dam (BPD) on the St Lawrence River from 2011-2013.  Eels were collected as they exited the Beauharnois eel passage facility and released a short distance upstream after tagging.  Recaptures (tag detections) occurred at two eel passage facilities located on either end of the Moses-Saunders Power (MSPD), 80 km upstream.  A total of 2,289 recaptures were recorded in 2011-2013; 1,264 on the west end of the dam and 1,025 on the east end.  Eels tagged and recaptured in the same year were more likely to be recaptured at the west end of MSPD, whereas eels recaptured in the second or third year after tagging were generally recaptured at about equal proportions on each end of the MSPD.  Average transit time between BPD and MSPD was 20.3 days for eels tagged and recaptured in the same year.  Minimum transit time to traverse the 80 km was 7.6 days (a rate of 10.5 km/day) and maximum time was 70.9 days.  Additional analysis will provide insights to upstream movement dynamics and estimates of population size in Lake St Francis.