Lake Sturgeon Population Demographics in the Huron-Erie Corridor, 1996-2012

The Huron Erie Corridor (HEC), encompassing Southern Lake Huron, St. Clair River, Detroit River, and Western Lake Erie contains one of the largest lake sturgeon populations in the Great Lakes.  Here we present population demographic information describing the status of three different spawning stocks in the HEC over the last sixteen years.  Mark-recapture assessments conducted in 1996-2011 have resulted in 1,657, 1,483, and 212, individually tagged lake sturgeon in Southern Lake Huron, Lower St. Clair River, and Detroit River, respectively.  Individual fish capture histories were input into POPAN and Pradel models in MARK to estimate population status, apparent survival, and seniority.  The estimated adult population size for the Southern Lake Huron stock is 26,689 (SE = 5,182), followed by the Lower St. Clair River 15,838 (SE = 3,364), and Detroit River 2,893 (SE = 1,154).  Seniority probability estimates were > 0.75 during most years, demonstrating the importance of adult survival in maintaining these stocks.  Adult apparent survival estimates were 83% and 77% for the Southern Lake Huron and Lower St. Clair River stocks, respectively.  Mark-recapture data has provided valuable information regarding the HEC lake sturgeon population; however additional assessment is needed to further understand the status of these stocks.