Upper McLeod River Trout Inventory, 2021-2022
Author(s)
Zachary Spence, Chad Judd, and Mike Rodtka
Summary:
Alberta Conservation Association staff sampled 76 sites located throughout eight HUC 10 sub-watersheds within the Upper McLeod River HUC 8 watershed in 2021 and 2022 using backpack electrofishing gear. We detected rainbow trout in each of the HUC 10 sub-watersheds, with the Upper McLeod above Sundance Creek HUC 10 having the highest relative abundance. Rainbow trout were the most widely distributed fish species we captured and the most abundant salmonid species. We detected bull trout in four of the HUC 10 sub-watersheds, with the Upper McLeod above Beaverdam Creek having the highest relative abundance. We captured 650 bull trout at 15 sites in the Mackenzie Creek drainage that repeated sites originally sampled by GOA in 2017. Use of Mackenzie Creek by spawning and rearing bull trout is well documented and it appears to be the only tributary of its kind in the upper Mcleod River watershed.
Stream substrate composition in the headwaters of the Upper McLeod River HUC 8 watershed was dominated primarily by cobble and large gravels, a habitat quality preferred by bull trout. Stream temperature also plays an important role in aquatic community processes and has been correlated to fish species distribution and abundance. Athabasca rainbow trout and bull trout are adapted to living in cold-water habitats, which limits their distribution to cold headwater streams within their preferred temperature range. Preferred temperatures for rainbow trout range from 7 to 18°C, while temperatures from 22 to 24°C are considered life threatening. Stream temperature measurements recorded during this study indicate that summer stream temperatures were suitable for rainbow trout throughout the Upper McLeod River HUC 8 watershed, whereas temperatures highly suitable for bull trout were limited to a few locations in the Upper McLeod above Beaverdam Creek, Upper McLeod above Gregg River, and Whitehorse Creek HUC 10 sub-watersheds.
Our study provides current information on stream habitats, and the abundance and distribution of at-risk Athabasca rainbow trout and bull trout, FSI priority species, within the Upper McLeod River HUC 8 watershed. This information is useful to land managers who must balance the diverse values of the land base upon which they operate and is critical for the conservation of native fish species that are particularly sensitive to habitat degradation.