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Windy Lake, British Columbia

In 1996, spiny-ray fish, which include yellow perch and smallmouth bass, were discovered for the first time in the Thompson River watershed, the last major drainage in the southern interior of British Columbia without established populations of these invasive species. 


Surveillance was expanded and by 2005 nine lakes were discovered to have established populations of spiny-ray fish. Five of the lakes were connected through waterways to the Thompson River, home to several species of Pacific salmon and endangered steelhead trout.


In 2006, the British Columbia Ministry of Environment began an aggressive campaign of rotenone eradication throughout the Thompson River watershed, culminating with the treatment of Windy Lake in 2017, the 12th waterbody restored under the program.    

At approximately 37 hectares in size, provincial staff engaged experienced volunteers and students from nearby Thompson Rivers University for the treatment of Windy Lake. It was completed in approximately 6-hours. Follow-up tests indicated that invasive yellow perch were eradicated. Mortalities were left in the water to provide a nutrient boost to the recovering lake ecosystem.

British Columbia's spiny-ray eradication program has successfully prevented the establishment of these invasive species in the Thompson River. 


A modified pontoon boat disperses diluted rotenone under the surface of Windy Lake, near Kelowna, B.C. in September, 2017. Photo ASF


Yellow perch, lake white fish, and rainbow trout are analyzed by students from Thompson Rivers University as part of a study on the effects of invasive fish species on small lake ecosystems. The fish were collected following the treatment of Windy Lake, near Kelowna B.C., in September 2017. Photo Neville Crabbe/ASF

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