Right: Sam, Heather and Cody pack up gear at the Kakwa cabin before our hike into Babette Lake. Fun fact: just the metal frame pack weighed 65lb! Photo: Claire Allore. Right: First day in the field at Kakwa Lake. Sam and Parker organize field gear and set up fishing rods while Cody assembles our zodiac. Photo: Claire Allore.
For 9 days this August, the Water and Fish team along with Alberta Environment and Protected Areas expanded on last summer’s Kakwa Watershed fish population study.
Left : Babette lake with Kakwa lake in the background. Photo: Sam Chevallier. Right: Part of Kakwa Lake. Photo: Claire Allore. Centre: The Kakwa Waterfall. Photo: Parker Makkreel.
The Kakwa watershed is home to Alberta’s beloved bull trout, a Species-at-Risk in Alberta. One threat to these native fish is the introduction of non-native species such as the rainbow trout. Rainbow trout have been historically stocked within the Kakwa drainage including in three (originally) fishless headwater lakes: Kakwa Lake, Babette Lake and Cecilia Lake. These lakes remain separated from the lower watershed by Kakwa Falls. This waterfall restricts bull trout movement upstream but does not prevent rainbow trout from moving downstream into bull trout territory. Given the limited records and information on these stocked rainbow trout, our project had two main objectives:
- Understand the relative abundance of rainbow trout above Kakwa Falls by sampling Kakwa Lake, Babette Lake, and connected tributaries.
- Confirm that bull trout or other native fish species do not exist above the falls.
Left: Sam prepping gear to be slung in a helicopter, while the helicopter fast approaches in the distance. Photo: Claire Allore. Right: the helicopter slinging gear. Photo: Sam Chevallier.
Once our team was safely helicoptered into the field we began a Mark-Recapture experiment to measure the population size of rainbows in each lake. Essentially, our team caught as many fish as possible, marked them via a fin clip, released them, and then deployed nets to see how many we could re-capture. For all fish that we captured with those nets, we also recorded length, weight, sex, stomach contents, and collected fin clips for genetics and stable isotope analysis, an otolith (ear bone) to determine ages of fish, and muscle tissue for mercury levels. All this information provides a wealth of knowledge regarding the fish in these lakes.
Left: Our field sampling station with Sam sorting through nets to find fish, Ben recording data in the background and Parker prepping a fish to look at stomach contents. Photo: Claire Allore. Right: Claire collecting otoliths (ear bones) from a fish. Photo: Parker Makkreel.
The data collection did not stop there! Our team electrofished a few of the rivers flowing into Kakwa Lake. The goal was to see if rainbow trout were using these rivers as well as the lake. We managed to confirm that many fry and fingerlings call these streams home.
Cody and Sam electrofishing. Photo: Parker Makkreel.
We also measured the oxygen levels and temperature at different depths of the lake to determine if there were any hypoxic areas or thermoclines to help us pinpoint where fish may prefer to live in the lake.
Left: Ben, Parker and Claire using a YSI probe to determine oxygen and temperature at different depths in Kakwa Lake. Photo: Parker Makkreel. Right: Sam sending Parker and Ben off to collect samples. Photo: Claire Allore.
Finally, our group wanted to get a bigger picture of how the food web was structured in these lakes. To do this we collected insect samples from both in and out of the water and periphyton (the slimy layer of algae and little organisms often found on rocks in a lake). These samples, along with the isotope fin clip samples from our fish, are given to a lab for stable isotope analysis that in turn provides insight into who eats who.
Left: A young rainbow trout caught ‘mid snack’ on another rainbow trout fry. Found while electrofishing the river between Babette and Kakwa Lake. Photo: Caire Allore. Right: Sam collecting bugs for isotope analysis. Photo: Claire Allore.
With our fieldwork in the Kakwa headwaters we were able to provide more clarity on the abundance of rainbow trout above Kakwa Falls and confirm that no other fish species exist above the falls.
Kakwa is a Cree word meaning porcupine. The lake is well named!
Top Left: The camp menace. Photo: Parker Makkreel. Top Right: A warning about the porcupines in the area. Photo: Parker Makkreel. Bottom: Sam, Ben, and Parker admire the local porcupine hiding under a bench. Photo: Claire Allore.
