by 2021 Outreach Assistant, Randy Paquette
On June 17, 2021, OWC’s Outreach Assistants spent the day at Trout Creek to complete westslope cutthroat trout redd surveys on behalf of Trout Unlimited Canada. Redds (spawning beds or “nests” where trout lay their eggs at the bottom of the stream) are a crucial component of the trout life cycle; they are how trout reproduce and ensure viable populations in our headwaters. By identifying and documenting the locations of redds, we can help protect sensitive trout populations and habitats.
“Redd surveys are an engaging and relatively low impact opportunity for volunteers such as citizen scientists to help in collecting valuable data which can be used to assess the health of fish populations. Data collected from these surveys can be used to quantify the effectiveness of a restoration project, identify important spawning areas for future restoration and protection, and to determine the timing and environmental variables which may trigger spawning in a watercourse.”
Native Trout Reproduction
Two of the native trout species found in the headwaters of the Oldman watershed, westslope cutthroat trout (WSCT) and bull trout (BLTR), are both listed as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Both species create nests, called redds, in which they lay their eggs. Redds play a vital role in the fish reproduction cycle and provide a microhabitat for the eggs to be fertilized. This process of fish laying eggs to be fertilized is called spawning.
Westslope cutthroat trout spawn in the spring, but may also spawn as late as early July in high mountain streams, depending on temperature. Bull trout spawn in the early fall in small creeks, where they overwinter and then hatch in March or April.
When finding a suitable location for a redd, trout prefer shallow, riffly streambeds that provide a constant flow of oxygen. The substrate must also be the right size; small gravel, no more than dime- or quarter-sized, is ideal. The female will turn on her side and use her tail fin to flip over the gravel to create a nest where she will deposit her eggs. This action attracts male trout, who come by and fertilize the eggs. A few weeks later, alevins (newly hatched trout with the yolk sac still attached) emerge!
Young westslope cutthroat trout. Photo by Jonny Armstrong
Redd Surveys
Before heading out into the field, we received training from Trout Unlimited Canada on how to conduct the redd surveys. It was a cloudy day when we drove to Trout Creek to put our training into practice. We brought all of our personal gear, which included our mobile phones to input the data that we would collect over the course of the day.
Once we arrived at the creek, we covered ourselves in bug spray and hiked to our first location. TUC had divided the creek into 1-km sections (called reaches) to provide more localized data assessments. For each reach we walked along the creek and searched for any possible redds. By the end of the day, we had surveyed two reaches, totaling over two kilometres in length.
One of several possible westslope cutthroat trout redds that we encountered while surveying Trout Creek in the Porcupine Hills. Photo by Randy Paquette.
Outreach Assistant Team Lead Sydney Taplin and Outreach Assistant Brandon Regier measuring a possible redd and inputting data into the database. Photo by Randy Paquette.
Redds can be difficult to spot, but if you look closely you may be able to see them. One distinguishing feature of redds is the clearing of algae on the bottom of a stream, so the substrate differs from the rest of the surrounding area. For example, it may look like rocks have been turned over with algae removed, and redds have a distinctive ‘tail’ of finer material. Once identified, we used a measuring tape to determine the approximate width, length, and depth of the redd. Redds vary in size, and can be one metre or more in length. Possible identification of species of trout was also recorded (in this case, WSCT - westslope cutthroat trout based on time of year and location). Data were recorded in the ArcGIS Survey 123 and the ArGIS Collector apps from Trout Unlimited Canada using our mobile phones. By the end of the day, we had found a few possible redds.
Risks to Redds
Westslope Cutthroat Trout are often referred to as “canaries in the coal mines,” as they are an indicator of water quality. They need clean water in order to survive and reproduce. Sedimentation (when dirt and materials from surface runoff are deposited in the water) is one issue that reduces water quality and threatens trout reproduction. Sediment increases with - and as a result of - decreased habitat quality due to cumulative impacts of human activities on the land, resulting in erosion, runoff, and the deposition of sediment in streams. Increased sedimentation causes a number of problems:
Too much sediment makes it difficult for fish to make their redd in the first place. Sediment can ‘cement’ the gravel together, making it nearly impossible for trout to dust off algae and dirt and dig the nest with their tail fins.
Fine sediment covers redds, which can suffocate the eggs. As a result, fewer or no alevins survive to hatch.
Too much sediment can leave baby fish vulnerable to predation. The buildup of sediment at the bottom of the stream fills in the spaces between pebbles where fry would otherwise hide from predators. This makes the fish easier targets for predation and prevents them from reaching maturity for reproduction.
Turbidity, a measurement of how cloudy the water is, has an impact on fish feeding. With more turbid waters, it is more difficult for fish to find food because the water is more opaque, and they are unable to see. Higher and longer durations of turbidity can also cause physical damage. Sediment can build up in fish and other aquatic organisms’ lungs, making them unable to breathe.
Erosion can lead to an increase of sediment introduced in water bodies that reduces habitat quality and puts stress on fish populations. Trout Creek, AB. Photo by Sydney Taplin
Who knew there was such a complex ecosystem beneath the water?! Luckily, there are actions we can take to help protect our sensitive trout populations.
Steer clear of creeks and streams. Staying clear of any waterbody and avoiding driving through them can help to protect the valuable habitat these fish need to reproduce and thrive. For producers, keeping livestock out of sensitive areas during vulnerables times of year (e.g. when trout are spawning, when riparian vegetation is recovering) will allow these natural processes to continue, resulting in healthier, more resilient plant and fish populations.
Stay on the trail. Using designated trail systems and bridges while enjoying the backcountry will reduce the amount of sediment going into the creeks and streams where fish may be spawning.
Don’t squish baby fish! Using bridges will reduce the chance of driving or walking over redds and/or fish that could get squished. By keeping wheels (and boots and hooves) out of water, it will help to reduce the impact of fish and their habitat.
Allow restored areas time to recover. OWC works with many partners to restore critical riparian habitat for our native trout populations. Give these areas time to regrow and recover by choosing an alternate route!
Volunteer! There are numerous volunteer opportunities; from helping to plant willow stakes to restore riparian habitat, to contributing to citizen science projects like redd surveys, you can help protect our sensitive species.
Outreach Assistants Sydney, Brandon, and Randy planting willow stakes to restore riparian habitat along a fenced-off creek containing cutthroat trout - under the curious gaze of cows congregated around their off-stream watering unit.
We would like to recognize and thank Trout Unlimited Canada for giving us the tools and training to help with their redd survey project at Trout Creek. Check out their website (https://tucanada.org/) to learn more about their work in conserving, protecting, and restoring Canada’s freshwater systems and how you can take part.
Cover Photo: 2021 Outreach Assistants conducting redd surveys along Trout Creek. Photo by Randy Paquette.
