Science Response 2015/036

Fish exclusion options for aquatic species at risk for drainage activities in Little Bear Creek, Ontario

Context

Little Bear Creek drains into the St. Clair River via the Chanel Ecarte in the Township of Dover of the Chatham-Kent Region. This small tributary is located approximately 10 km south of the town of Wallaceburg, Ontario. Little Bear Creek is home to several species at risk (SAR) fishes including Pugnose Shiner (Notropis anogenus), Lake Chubsucker (Erimyzon sucetta), Grass Pickerel (Esox americanus vermiculatus), Blackstripe Topminnow (Fundulus notatus), Spotted Sucker (Minytrema melanops), and Pugnose Minnow (Opsopoeodus emiliae). Little Bear Creek, a tributary of Lake St. Clair, is classified as an agricultural drain and has been identified for drain maintenance by the Region of Chatham-Kent. There is increasing pressure to complete a drain clean out of Little Bear Creek with the goal to decrease flooding of land owned by private landowners.

The Municipality of Chatham-Kent has submitted a “Drain Maintenance Request” under the provincial Drainage Act to excavate and remove accumulated sediment from the Little Bear Creek Drain. In-water works are proposed from the mouth at Chenal Ecarte upstream for 29.5 km to Countryview Line, where the remaining drain portions are buried. Excavation will be a combination of drag-line crane rigging, and long and standard hydraulic excavators.  A number of culvert and enclosure works are also proposed in the headwater areas of the drain. Small brush and larger trees are also to be removed from the shoreline along the entire length of the drain.

There is a concern that a full agricultural clean out of Little Bear Creek will negatively impact aquatic species at risk and their habitat. This science response complements an existing Canadian Science Advisory Secretariat (CSAS) request to evaluate mitigation measures within various reaches of Little Bear Creek to minimize the potential impacts of the proposed drainage work on Pugnose Minnow, Blackstripe Topminnow, Pugnose Shiner, Lake Chubsucker, and Grass Pickerel. To provide science advice for the current request, the practicability of fish exclusion techniques to reduce harm to SAR fishes during drainage activities was examined.

Fisheries and Oceans Canada (DFO) Species at Risk Program requested that DFO Science address the following questions regarding agricultural drain maintenance mitigation within Little Bear Creek.

1. Could fish exclusion be used as a mitigation strategy to minimize harm to SAR fishes present in Little Bear Creek in the area proposed for drain clean out?
2. Would reach-specific physical parameters (e.g., size of waterway, water clarity) compromise the effectiveness of fish exclusion?
3. Could the resulting fish exclusion techniques be practically implemented on the scale required for Little Bear Creek?

This Science Response Report results from the Science Response Process of April 2015 on Options for exclusion of fish species at risk for drainage activities in Little Beach Creek, Ontario.

Complete document (PDF, 2550 KB)

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