**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the author at Lisa.OConnor@dfo-mpo.gc.ca or via telephone at 705-941-2671. Questions? Contact the GLFC via e-mail or via telephone at 734-662-3209**

Review of Credit and Duffins River Dams to Determine Sea Lamprey Escapement

L. M. O’Connor^a, T. C. Pratt^a, T. B. Steeves^b, P. Sullivan^b

^a DFO-GLLFAS, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 2E5

^b DFO-SLCC, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 2E5

December 2012

Abstract

Barriers must be consistently able to block spawning sea lampreys in order to remain an important component of an integrated sea lamprey management program. The Credit River dam at Streetsville is a former mill dam that has been modified to block sea lamprey migration and Duffins Creek is a purpose-built low-head barrier. Both barriers are located on streams tributary to Lake Ontario and both have been of considerable value to the sea lamprey control program; however, both dams have a consistent, recent history of sea lamprey escapement. In 2010 we began an assessment of both barriers in an effort to determine the route escapement and this continued in 2012. We used large in-stream passive integrated transponder (PIT) antenna arrays to monitor PIT tagged sea lampreys that were released into the rivers below the barriers. In 2010, in Duffins Creek we found sea lampreys breached the barrier by crossing the south crest of the dam, however, during periods of higher flows, we found the barrier crest was completely inundated, which may lead to other opportunities for sea lampreys to move upstream. In 2010 at the Streetsville dam we did not record any sea lampreys passing either the dam crest or the fishway, however, mechanical and technical issues with the antenna array may have contributed to our lack of success. Lampreys were reported in the river upstream of the barrier in 2010. In 2012, we again monitored the Streetsville dam using PIT antenna arrays and PIT tagged sea lampreys. We recorded sea lampreys passing over both the main and western crests of the dam and we also recorded sea lampreys escaping upstream through the open weir and pool fishway.

We recommend an engineering report to determine the feasibility of repairing the Duffins Creek dam. We also recommend repairs to the Streetsville dam with regards to the missing steel lip and potential areas of escape where the lowered centre crest joins the western crest and a review of the join at the eastern crest to ensure that a similar area of concern does not develop. With regards to the fishway, we recommend that the Sea Lamprey Control Centre engage both the Ontario Ministry of Natural Resources (OMNR) and the Credit River Angler Association (those contracted by OMNR to operate the fishway) along with Kraft Canada, the owner of the dam, to develop a more suitable plan for the operation of the fishway during the sea lamprey spawning migration.