A Season of Change at Baker Lake

This article was originally published in The Midden – Great Basin National Park: Vol. 20, No. 2, Winter 2020.

Using the pack raft to take a water quality profile of Baker Lake.

NPS Photo by Jonathan Reynolds

By Leslie Twiner, Biological Science Technician
Sitting at 10,620 feet and surrounded by a breathtaking cirque, Baker Lake remains a popular attraction for backpackers and day hikers visiting the park. From June through October, I was fortunate enough to be able to spend time working and camping at Baker Lake. I got to know the intricacies of this lake and the ecosystem it supports. Throughout the season we collected a wide variety of data to give us a better understanding of Baker Lake and the population of trout it currently supports.

Baker Lake is currently home to a healthy population of Brook Trout and Lahontan Cutthroat Trout. These fish are not native to the park and were stocked in the lake before the area became a national park. In September, we introduced native Bonneville Cutthroat Trout (BCT) into neighboring Johnson Lake. In the years to come, we hope to also introduce BCT into Baker Lake and create a new, thriving population of native trout for future generations to enjoy. A large part of our work this season has been preparing Baker Lake to be treated with the piscicide rotenone in the summer of 2021. Treating the lake with rotenone will allow the park to remove all nonnative fish before BCT are introduced.

Hiking up gear to stash at Baker Lake for the summer.

NPS Photo by Jonathan Reynolds

Due to changing climate, habitat for BCT is quickly disappearing. BCT rely on cold mountain streams that run year-round in order to survive and reproduce. With increasing droughts and warmer temperatures becoming the norm, it is becoming increasingly difficult for BCT to survive in their native range. Our hope is that by creating two new populations at high elevations in historically fishless lakes, we will create refugia populations that can survive changing climate.

Our first step in preparing Baker Lake for next year’s treatment was to perform snorkel surveys throughout the lake to document successful spawning of Lahontan Cutthroat Trout. Our first few trips up to Baker Lake, we put as much gear as we could carry on our backs and made our way up the trail to the lake. Once we arrived at the lake, we put on dry suits and snorkels and started the process of observing the fish in the lake. Our hope is that if Lahontan Cutthroat Trout are successfully reproducing, this is a good sign that Bonneville Cutthroat Trout will also be able to reproduce and create a self-sustaining population. When snorkeling in the lake, we were able to document what we believe is spawning behavior.

NCC all women’s crew member taking depth measurements at Baker Lake.

Stephanie Greenwood

We also deployed a water quality sonde into the lake. The sonde takes measurements such as pH, dissolved oxygen, conductivity, and temperature. This instrument allows us to get a water quality profile of the lake. This gives us a better idea of how effective the rotenone treatment will be and how much rotenone will need to be used in the lake.

In order to measure the lake and get a profile of the lake depth, we conducted a bathymetric survey with the help of the women’s Nevada Conservation Corps (NCC) crew. The survey involved creating a 5m x 5m grid in the lake and taking depth measurements every 5 meters. This tells us how deep the lake is and how much water is in it.

We also picked multiple reference points to measure their distance to the water. Then, when the water levels are higher, we can compare measurements using those reference points and extrapolate that change to the rest of the lake. This information gives us a better idea of how to properly prepare for the rotenone treatment and guarantee its success. Once the nonnative fish have been removed from the lake, Bonneville Cutthroat Trout will be reintroduced in order to create a new population that will hopefully be more resilient to survive a changing climate in years to come.