Yellow Chromer

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Pond Weed Removal Program

    In the first week of June this spring, local volunteers, which just happen to be fly fishers, conducted a weed removal project on the Lower Mitford Trout Pond. The group’s objective was to clean out as many of the weeds in the pond as possible, before the annual “Kids Can Catch” event took place on the 17th of June.

    Each year, the kids fishing event on the two Mitford Trout Ponds is something that many young anglers and parents look forward to participating in. Keeping the weed density in the ponds helps reduce the amount of frustration that young anglers have to deal with in their first attempts at becoming trout fisher’s.

    The system used for weed removal is a simple but effective technique that has been used on the ponds for the last few decades. A length of 1/4 inch steel cable, with rope tied to both ends, is used to uproot the tall pond weeds from the bottom of the ponds. Once freed from the bottom, the weed will float into the shoreline, where they can be gathered and hauled away.

    The weeds are raked up onto the shore, where they can dry for easy collection. The annual program only takes a few hours to complete, if you have the necessary volunteer support to chip in. Fortunately, the volunteer fly fisher’s that helped out this year, all fly fish on the ponds from time to time, so they are definitely stakeholders in the heath of the pond’s fishery.

    There may be another weed removal project on the ponds, later on in the summer, when warm weather and plenty of sunshine will promote new weed growth. The spring weed removal will help reduce the work load for the late summer program.

    The key to a successful outcome using this technique is too move slowly, once the steel cable is positioned for the pull. This will allow the cable to keep in contact with the bottom, as the rope is pulled on both ends. Using a steel cable allows for easy weed removal on any weeds that are wrapped along the cable when it is drawn into the shoreline.

Above: In this photo, the cable is positioned for a pull on the west side of the lower trout pond. There were two volunteers on each end.

Above: This is a photo of the bottom weed growth, before the clean out on the lower Mitford Trout Pond.

Above: The weeds have been displaced from the pond bed and they are now floating on the surface. The wind will blow them ashore.

Above: This sketch shows how the weed removal technique is used on the Mitford Trout Ponds.

The Different Stages of Stream Bank Erosion

    Without the deep root systems of native willows and trees to stabilize stream banks, erosion occurs over time. This erosion is significant on the outside bends or meanders of the stream channel. Native grass and sedge root systems are too shallow and weak to withstand the toe erosion on elevated stream banks.

    As the stream bank is eroded at water level, undercutting occurs and eventually, the sod will fold down and collapse. During this process, large volumes of silt enter the stream system. The first sign of a failing stream bank is when the shoreline grasses fold down towards the water’s surface. Eventually, the sod will

break free and fall into the stream channel.

    This will expose the soil beneath, which is washed into the stream channel and will continue to slide until the slope stabilizes. Then the whole process will begin again. By planting willows on these critical and collapsed stream banks, the banks are stabilized over time.

Under Cutting

Stream Bank Collapse

Exposed Soil

Toe Erosion

Sod Falls into  the Stream Channel

Expose Soil Continues to wash into the Stream

Planting on Eroding Stream Banks

    When a eroding stream bank is exposed or in a state of collapse, native willows are planted into the exposed soil, close to the surface of the water and further up the capillary fringe. The root systems of the native plants will stabilize the eroding stream bank over time. Multiple plantings are required to

insure that enough plants establish themselves on the eroding stream banks.

    The best time for planting is post spring freshets, after high flow levels in the stream. The plants will have the whole summer and fall to develop deep rooting on the exposed stream bank.

Planting on a Collapsed Bank

Planting on Exposed Soil

Stabilizing an Eroding Stream Bank with Native Willows

    A large part of the “Bow Valley Riparian Recovery and Enhancement Program” objectives is stream bank stabilization. Areas on the stream channel where eroding stream banks contribute large amounts of silt loading into the stream annually. Most of the sites are located on the outside bend, meander or oxbow of a stream channel.

    Stabilization is achieved by planting native willows and trees on the exposed soil of severe or moderate eroding slopes. The objective of these plantings is to established a network of willow and tree roots to re-enforce the loose soil over time. The other benefit is to create habitat along the stream channel.

    The process is a simple approach, but very cost effective and time efficient. A stabilization planting treatment is carried out over a few years of planting, until

enough surviving plants are established to firm up the banks. When completed, the site is natural in appearance, yet very efficient.

    Bow Valley Habitat Development and its partners have been conducting these type of stream bank stabilization sites for years now, and the results have been very positive. Improved water quality and better fish and wildlife habitat are the end result. The first projects were completed on the Bighill Creek, in the Town of Cochrane.

    There have been similar stream bank stabilization plantings on both West Nose and Nose Creek, since the program first started in 2014. This work will continue into the future, with high expectations on helping to transform the riparian habitat and improve the water quality in all three streams. Bow Valley Habitat Development will continue to monitor the sites.

Above: Before photo; this eroding stream bank on Bighill Creek was planted with native willows to help stabilized the eroding bank.

Above: After photo; this is the same stream bank erosion site a few years after native willows were planted. The eroding stream bank is now stabilized and no more silt loading is occurring.

New Whirling Disease Lab

    This year, Alberta opened the first whirling disease lab in Canada. The facility is located in Vegreville, Alberta. The lab is an InnoTech facility with $2.9 million dollars for operational costs and 6 full time research technicians. The initial goal is to determine the spread of the disease in our province. Further research on the disease will also be conducted.

    Over the past two years, it has been discovered that the parasitical disease has been wide spread throughout the southern part of our province. Positive test samples of whirling disease have been found in the Bow River, Crowsnest, Oldman and Red Deer River systems. By having a lab set up to focus on this scourge to our sport fishery, hopefully, this approach will help our province reduce the chances of spreading it to other watersheds.

    Measures to educate the public about precautions that they can take to help stop the spread will also be put in place.


What is Next?  -  With Whirling Disease

    Once the spread of whirling disease in our province has been thoroughly understood, the next step in research may well be to determine whether any of our rainbow and cutthroat trout strains have some resistance to the disease. If so, there is a possibility that either natural selection or captive breeding will develop a disease resistant population.

    In the USA, there are studies being carried out to rear rainbow trout that are resistant to the M. cerebralis parasite. Juvenile trout are exposed varying quantities of the Myxospore, then those trout that are effected the least, are selected for further breeding. In

nature this is called natural selection.

    By conducting a selective breeding program in a controlled scientific environment, the natural selection process is sped up. Over time, a disease resistant rainbow trout is available to introduce back into the wild.

    A strain of Kamloops rainbow trout managed to evolve into a whirling disease resistant population in Europe, thru the natural selection process, so this has already proven to be possible. This strain was called the “Hofer Strain” of rainbow trout. However, this development of a naturally resistant rainbow  takes time.

Whirling Disease in Alberta Cutthroat Trout

    It is still too early to know how the whirling disease will impact our native strains of cutthroat trout in Alberta. If the disease finds its way into the Job Lake populations, which are used for stocking high mountain lakes, the loss could be substantial. We already know that the Johnson Lake fishery in Banff Park was infested with the disease, but there is no word yet on the Job Lake population and other stream populations, from what I have heard so far. With the cutthroat trout being a threatened native trout, this threat from the disease is especially important.