Cal Trout establishes refuges for Lahontan Cutthroat Trout.
While fishing enthusiasts gear up for the start of Mono and Inyo County fishing season, non-profit California Trout (CalTrout) is preparing for its season of fieldwork restoring historic Lahontan Cutthroat Trout habitat in the Walker River Basin.
Lahontan cutthroat trout (LCT), recognized by their yellow coloring, heavy black spotting, and red slash under the jaw, are native to the Walker Basin. They are the largest species of cutthroat trout, often exceeding 10 pounds in lakes, and are a distinct subspecies of cutthroat trout native to California, Nevada, Oregon, and Idaho.
While once prolific throughout the Walker Basin—and a vital part of both Native American and European settler diets—LCT are currently listed as threatened under the Endangered Species Act.
Here in California, LCT may now be at risk of extinction. That’s because many non-native trout, including brook and rainbow trout, now dominate historic LCT habitats. These species threaten LCT populations due to competition, predation, and hybridization.
The California Department of Fish and Wildlife (CDFW) introduced Brook trout to the area for recreation; however, as it turns out, LCT may have a better chance at surviving these drought conditions, and future extreme conditions resulting from climate change.
According to Dawne Emery of CDFW, LCT evolved in the Walker Basin, and have endured both a 140-year and 200-year drought historically.
“These fish were able to survive and persist, so they’re used to drought,” she said. “Granted, back then they had the whole Basin to find refuge; now they’re stuck in a few isolated headwater streams where they don’t have the ability to interact and interbreed with each other.”
But, she added, “They’re adapted to the alkaline water we’re going to get, and perhaps warmer water temperatures. They have that ability to persist.”
CalTrout began the LCT restoration project in 2011 with CDFW, and currently coordinates the project with Trout Unlimited, the National Fish and Wildlife Foundation, and the Southwest Council Federation of Fly Fishers.
Seasonal field crews hired and managed by CalTrout clear vegetation, eradicate non-native brook trout, and construct modified Alaskan weirs to inhibit fish migration upstream or downstream of the Slinkard and Silver Creek headwaters.
After last year’s fieldwork, 1.5 miles of Slinkard Creek and 2 miles of Silver Creek were completely free of brook trout, and are now new refuge areas for LCT.
Clearing these miles on Slinkard and Silver is far from easy. As CalTrout Watershed and Outreach Coordinator Andrew Skaggs explained, in 2014, seven seasonal employees in two crews constructed a total of 18 temporary fish migration barriers, one every 100 meters, to block off distinct stream segments in both Slinkard and Silver.
Each crew consisted of two shockers, two netters, and a data entry person. Shockers used electrofishing equipment—picture the Ghostbusters’ proton packs, and you’ll have a good idea what they look like—at 300-500 volts to stun fish for about 10 seconds.
Netters then caught all stunned fish, and crew members sorted these fish by hand, counting and collecting data before killing non-native brook trout and relocating native LCT to an area upstream of each weir. Crews “electrofished” until they completed three brook trout-free passes.
“Once we had that, we would wait overnight, then re-fish that section three times; if on any of those passes we found a Brook trout, the cycle would start all over again,” Skaggs said. “We’d do eight 10-hour days, and then we have six days off.”
“Eradicated” brook trout didn’t go to waste—they were used in a trade with the Marine Mountain Warfare Training Center “for electricity to charge our lead acid shocking batteries,” Skaggs said.
The lead acid batteries alone weigh 18 pounds. The entire electrofishing pack, which shockers wear for most of each 10-hour work day, weighs around 35 pounds.
That’s just one challenge of many for the seasonal crew. Skaggs said that because of the remote setting of both creeks, members have to hike in absolutely everything they use. Meanwhile electrofishing itself is a combination of physical and mental toil: “it requires intense focus all day to ensure that every last brook trout is removed and eradicated,” Skaggs said.
Yet the work also has its own rewards. “You’re in a beautiful backcountry setting, working and collaborating with volunteers and great staff, and you’re working to protect and restore a federally threatened species,” Skaggs said. “… And you get delicious, fresh trout for dinner.”
Although the 2014 field season greatly expanded the LCT refuge areas in Slinkard and Silver Creek, Skaggs said there’s more work to be done.
“To finish Slinkard, we need three more field seasons, and to finish Silver, we need eight more field seasons,” he said. “To finish means we fish until there is a natural barrier where Brook trout are unable to migrate upstream. In both cases, it’s a massive waterfall that no fish could ever get up.”
While electrofishing may not seem like the most time-effective way to clear the streams, Skaggs noted that a simpler solution, the use of piscicides, is controversial at best in California.
“Some projects, like the Paiute Cutthroat Trout recovery project in Silver King Canyon, which is the watershed north of Silver Creek, have been doing a chemical treatment using a piscicide called rotenone,” he said. “However, litigation and costly court fees have cost the CDFW over $1 million, so mechanical treatment is a less controversial and more feasible means in California to eradicate fish.”
While some in the local fishing community have met the restoration project with resistance, the project’s end goal is not to prohibit fishing, nor completely eradicate non-native species in the Walker River Basin. Silver Creek is closed indefinitely to fishing, but upstream Slinkard is currently open for catch and release angling using artificial flies with barbless hooks, and lower Slinkard is open for angling with a bag limit of five fish and no gear restrictions.
CalTrout aims to expand LCT habitat and angling throughout more of the Walker Basin, said CalTrout Eastern Sierra Regional Manager Mark Drew. “Ultimately, CalTrout would love to see these streams opened up for recreational angling opportunities for generations to come,” he said.