**The title, authors, and abstract for this completion report are provided below. For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**
Evaluation of modification to improve fishway performance
T.C. Pratt1, L.M. O'Connor1, A. Hallett2, R.L. McLaughlin3, and D.B. Hayes4
1Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries & Oceans Canada, 1 Canal Dr., Sault Ste. Marie, ON, P6A 6W4
2 Sea Lamprey Control Centre, Fisheries & Oceans Canada, 1 Canal Dr., Sault Ste. Marie, ON, P6A 6W4
3 University of Guelph, Guelph, ON, N1G 2W1
4 Michigan State University, East Lansing, MI, 48824-1222
We experimentally modified fishway trap and funnel size to determine whether increasing trap size and decreasing funnel size could improve fish passage at two trap-and-sort fishways operated in conjunction with low-head barriers used as part of an integrated sea lamprey management plan. Fish passage improved two-fold over an earlier assessment, with passage rates of 10% and 57% at Cobourg Brook and Big Carp River, respectively, suggesting that increasing fishway size and reducing funnel size was successful in improving overall fish passage. However, the modelling of daily fishway catch, fishway attraction, trap attraction and retention and passage efficiencies with seasonal, thermal and hydraulic variables and different fishway configurations identified a number of complicating factors that make proposing simple changes to trap size or funnel designs more problematic. Smaller funnels will likely result in a net benefit to fishway efficiency, as they rarely negatively affected fishway performance, but increasing trap size resulted in both positive and negative outcomes. Unfortunately, flow conditions at the two fishways were quite different, and the modelling outcomes suggest that protocols for fishway operation may need to be developed on a site-by-site basis.