WESTLOCK – Rainbow Park, a popular, 20-acre Westlock County owned day-use picnic site and trout fishing pond roughly six kilometres east of town, won’t see its fish stocks replenished until the fall to try and fix a problem that it and many other stocked ponds face — fish not surviving beyond mid-summer due to a decrease in the level of dissolved oxygen.
Northern Lights Chapter/Trout Unlimited Canada treasurer Peter Little, who does releases for the group and also writes for the Alberta Conservation Association (ACA), explained that the provincial Fish and Wildlife division stocks many of Alberta’s lakes, but most of the fish ponds in Edmonton and the area immediately north receive their new stock of trout each year from the ACA. And while the ACA’s stocking trucks are slated to roll prior to the May long weekend out to Morinville, Lacombe, Gibbons, Lamont, Radway, Legal and Fort Saskatchewan, Rainbow Park has been delayed until the fall.
Little says the problem faced at Rainbow, as well as many other ponds, is related to an increase in nutrients in the water — primarily nitrogen and phosphorous — which decrease the level of dissolved oxygen in the pond. During an April 11 interview, he said he “very much doubts” there’s any live fish currently in Rainbow as “there was a big die-off right after mid-summer 2022” and “doubts any survived the winter.”
“All aquatic animals need dissolved oxygen to survive and its decrease, where water quality is an issue, is leading to the death of fish. To add to the problem, summer temperatures are becoming higher and warm water doesn’t maintain dissolved oxygen as well as cold. Algae blooms and summer fish-kills are also becoming more frequent,” he writes.
Little says there’s not much the ACA can do about the higher temperatures, but they researched the science on water quality, did some testing of their own and came up with a solution that Alberta Environment and Parks approved as meeting the requirements of the Environmental Protection and Enhancement Act.
“It involves treating the pond with a very specific amount of alum that will maintain more favourable water quality for fish and invertebrate survival by significantly reducing phosphorus concentrations,” he explained. “Improved water quality will help keep dissolved oxygen levels higher through summer, fall and into the winter. If this works as expected, then it will be good news not only for Rainbow Park Pond, its fish and anglers, but for many other ponds experiencing the same problem.”
Little said after the work is done this summer, a stocking truck will head to the site, but there probably “won’t be as many (fish) as normal, at least for this year.” He also added that if there’s a “pond in your area not on the fish stocking list that you think might make a good recreational fishery, please let the ACA and your local council know.”
“One of the big stocking trucks can carry 20,000 fish but they go to more than one pond at a time. There’s all sort of protocol that they have to go through because they have to disinfect the tires as they travel from pond to pond,” he added.
Rainbow Park, located four miles east of Westlock on Highway 18, then a half mile south of Highway 18 on the west side of Range Road 255, includes the pond, plus a sheltered picnic building, numerous fire pits, picnic tables and plenty of open space for outdoor activities and games.
In an April 12 e-mail, county community services coordinator Adrienne Finnegan noted the municipality “recently acquired Rainbow Park Pond and the surrounding lands of approximately 20 acres from the Province of Alberta” and are “currently working on plans to improve the park.”