Submitted by Jackson Olsen and Charles Ewing
Do you enjoy a day on the lake with the family fishing for trout? A weekend out with the mates? Imagine your favourite fishing spot getting eradicated. That is the reality for those who frequent Emerald Lake in Yoho National Park. As the first suspected case of whirling disease within British Columbia, this is the most likely outcome.
Parks Canada states the lake may have to be euthanized to prevent the spread. Euthanizing a lake is the removal of all living organisms within the affected lake via chemicals, ridding it of all potential pathogens. However further testing is still required to ensure that it is the proper course of action. Until then, Parks Canada has closed all the surrounding tributaries and lakes connected to Emerald Lake to the public.
Parks Canada employees first noticed whirling disease in 2016 in Banff National Park’s Johnson Lake; all the fish within the lake were euthanized to prevent the spread.
Whirling disease is an infection caused by the parasite Myxobolus cerebralis, it does not spread directly from fish to fish but via a parasite that piggybacks on the worm (Tubifex tubifex). It affects salmonids such as rainbow trout, bull trout, coho salmon, and sockeye salmon. The spread of whirling disease occurs via infected live or dead fish carrying infected worms, or via equipment with contaminated soil, or contaminated water.
The signs of infection include fish swimming in a whirling pattern, and skeletal deformities that look like someone pinched and twisted the tail. The fish often present with a darkened black tail. Whirling disease has a 90 per cent mortality rate within affected young fish. If you see fish displaying these symptoms, be sure to report them immediately to your local CFIA Animal Health Office.
British Columbia relies heavily on tourism during the summer months, with 24 per cent of tourists partaking in ocean or freshwater fishing which totaled 1.4 million people between 2007 and 2009. A large part of Canadian tourism happens within national or provincial parks. Whirling disease has the potential to restrict access to lakes and waterbodies or close areas that attract tourism and revenue in isolated communities that rely heavily on this. In 2015 anglers contributed a total of $7.9 billion to local economies.
If whirling disease were to infect a major river basin such as the Columbia River basin, it would have detrimental impacts. The fish are integral to the ecosystem, as food for larger fish when they are young, to the end of their life when they wash ashore and are absorbed within the riparian zone by the plants, and animals that frequent them (the riparian zone is the transitional zone between the water and upland vegetation).
If a substantial percentage of fish within the food chain are suddenly removed, it would create a lack of food for those above them and allowing those below to grow exponentially when presented with the lack of threat. The loss of these fish can have significant economic and cultural repercussions.
Increased public awareness will reduce the potential or spread of whirling disease. You can do your part by following the clean, drain and dry method outlined by the Government of Canada. This is to be done to all vessels and equipment such as boats, waders, and felt-soled boots when entering a new waterbody that is not connected to the previous one you were in. Not only will this help limit the spread of whirling disease but also the spread of other aquatic invasives. Do your part and help keep Canadian waters pristine.
Jackson Olsen and Charles Ewing are second year Recreation, Fish and Wildlife students at Castlegar’s Selkirk College.
