Chris Downs, fisheries biologist and leader of native trout protection efforts, recently spoke at Science and History Day to update the public on the Park’s lake trout suppression and bull trout translocation projects.
Bull trout are being outcompeted by larger, longer-lived lake trout in many water bodies in the Park. The native bulls need clean, cold, complex, and connected water to thrive, and they’re threatened by climate change as well. With a 2 degree increase in Celsius, which is the standard for rising temperatures allowed by world leaders, lake trout could dominate all lakes and bull trout would be functionally extinct.
In Quartz Lake, lake trout suppression through gill netting has proven to be very effective to reduce lake trout numbers while keeping bull trout populations stable. In the spring, the team nets juvenile lake trout, and in the fall they return to catch adults.
“It’s not a chicken or an egg type thing,” Downs said. “You remove the adults, you have less babies. You remove the babies, you have less adults eventually.”
There’s been a learning curve for the process, with more lake trout caught a couple years after the project began in 2009. However, the numbers are dropping now, especially for juveniles.
Bull trout populations have been consistent throughout the lake trout suppression project.
In areas like Logging Lake, though, bull trout have lost the battle. That’s why Downs and others are collecting juvenile bull trout from Logging Creek and Quartz Lake and relocating them to upstream Grace Lake, where lake trout haven’t invaded and where bulls will be more protected from climate change.
Young from three different females were collected, for a total of 750 juveniles spread out across Grace Lake. This year, the crew will collect eggs from four more Quartz Lake females to transport to Grace Lake, and next year they’ll introduce 150 1-year-old bulls there as well.
“It’s thinking out of the box. Not a lot of folks are doing this,” Downs said of the translocation project. “We can’t do everything everywhere, but in some places it seems reasonable to me. The end game is to get rid of the non-natives and protect the natives.”