by Jeniffer Solis, Nevada Current
A small, unassuming two-inch mussel could stall the comeback of Nevada’s threatened Lahontan cutthroat trout and endangered cui-ui sucker, but the Pyramid Lake Paiute Tribe, long time steward of the lake, has made it a mission to prevent invasive species from establishing themselves in the lake.
The Lahontan cutthroat trout were believed to have gone extinct in 1943, due to a dam that blocked their spawning ground, and the cui-ui were expected to follow.
But in a strike of luck, a fishery scientist eventually identified a remnant population of the Lahontan cutthroat trout surviving in a creek on the Nevada-Utah border. The remarkable find allowed the tribe to propagate the trout and successfully reintroduce it into Pyramid Lake.
The tribe now operates three hatcheries to produce both the trout and cui-ui. But those hatcheries are facing new challenges: invasive species like the destructive quagga and zebra mussels.
The Pyramid Lake Tribe’s aquatic invasive species program is a new effort designed to preserve the federally endangered and threatened fish species in the lake. The tribe received a grant of nearly $200,000 from the U.S. Fish and Wildlife Service in November that will help pay for additional seasonal staff at the Pyramid Lake Paiute Tribe inspection and decontamination station next to the highway in Sutcliffe to intercept watercraft on the way to the lake’s boat launch.
Continued collaboration between the federal government and the tribe is essential to the recovery of the fish, said Dan Mosley, Director of the Pyramid Lake Fisheries.
“The tribe has their own expertise. It’s part of the traditional ecological knowledge we have and incorporate into raising these fish,” Mosley said. “We combine our expertise and resources. We work together to keep these fish going.”
Traditionally both, the Lahontan cutthroat trout and cui-ui sucker are important to the culture of the Paiute people. The Pyramid Lake Paiute Tribe refer to themselves are the “Kooyooe Tukadu” in their native language, or “people who eat cui-ui.”
“We want to be able to keep our program going to be able to prevent the introduction of aquatic invasive species and continue our management practices,” said Adrienne Juby, the environmental specialist for the Pyramid Lake Paiute Tribe’s aquatic invasive species program.
Quagga mussels and zebra mussels, native to the Caspian Sea, are among the most destructive aquatic invasive species known and have spread across the nation’s waterways, including Lake Mead.
In Lake Mead and Lake Mohave, quagga mussels have caused millions of dollars of damage by clogging water intake pipes, encrusting boats and facilities, altering the food chain, and disrupting fish spawning. The Bureau of Reclamation estimates that the maintenance bill for clogged hydroelectric cooling pipes in Hoover Dam to be $1 million per year and will likely increase over time.
The Pyramid Lake inspection station was completed in 2018, but the station was not in operation until this October. Similar boat inspections at Lake Tahoe have intercepted quagga mussels, said Juby, an example of the importance of a fully staffed inspection station.
“Since we opened Oct. 1st, we’ve inspected 140 boats and we’ve had to decontaminate a third of those boats,” Juby said. “A lot of folks don’t understand that a tiny droplet of water can harbor aquatic invasive species and start a whole new infestation.”
If the mussels establish themselves at the Pyramid Lake fisheries or the recently completed $48 million retrofit of the dam to facilitate fish passage, the dramatic recovery of the fish could be reversed. The maintenance cost to the Pyramid Lake fisheries, a major part of the lake’s recovery, would be unprecedented, said Mosley.
“Because of all the upstream dams, all the dams on the river diverting water for municipal use or irrigation, the hatchery is kind of like a Band-Aid system,” Mosley said. “That’s what I call it because if we didn’t have those hatcheries there it would be really tough for those fish to survive on their own.”
Quagga mussels can survive up to 30 days without water and stow away on boats that have entered infested waters. The mussels are also extremely effective filter feeders, which allows them to reduce the amount of phytoplankton—the base of the lake’s food chain—available to other organisms.
Competition for phytoplankton could strain the food chain in the lake, resulting in less food for the endangered cui-ui sucker, and it’s natural predator, the Lahontan cutthroat trout.
While the Truckee River, which feeds into Pyramid Lake, does not have quagga mussels at this point, the river does have an invasion of watermilfoil, an invasive plant that reproduces so rapidly that it can reduce oxygen levels in the water and clog up channels by trapping extra sediment.
“That is a concern, it’s why we’ve started monitoring,” Juby said. “That way we can track the population’s movement.”
Pyramid Lake is sacred to the Paiute people, both culturally and spiritually. The lake is also the greatest source of income for the tribe. The past extinction of the Lahontan cutthroat trout in the lake is a reminder of what the tribe stands to lose if the trout’s recovery is hampered by invasive species.
“Pyramid Lake still had a lot of fish back then, before the 1930s. That was the economy of the tribe. It provided a lot of money for tribal members back then. When the population died out, we had to find other ways to survive and make a living,” Mosley said.
The Lahontan Basin, where the Pyramid Lake Paiute Reservation sits, looks very different today than it did 90 years ago. Once home to two lakes, the reservation now has only one.
All that remains of the now dead Lake Winnemucca is a dusty depression just east of Pyramid Lake, drained completely by combination of water diversion projects, roads, and agricultural use.
Once part of the Lahontan sea, the lakes are remnants of the ancient sea which covered a surface area of over 8,500 square miles. As the climate dried, the Pyramid and Winnemucca lakes became separate lakes, only connected by a wetland that has since also dried out.
Large trout populations in both lakes helped sustain the Pyramid Lake Paiute Tribe when they were rounded up and placed on a reservation, cutting them off from their traditional homelands and food sources.
But the completion of the Derby Dam in 1905, which diverted significant flows to agricultural fields near Fallon, contributed greatly to the destabilization of the lakes and their inhabitants, resulting in the destruction of Lake Winnemucca.
During this period, Pyramid Lake also declined. It’s estimated the lake dropped by as much as 80 feet by 1967. As the lake levels dropped so did the number of Lahontan cutthroat trout and the cui-ui sucker, as access to spawning grounds in the Truckee River base were blocked by the dam.
“They pretty much disappeared,” Mosley said. “The lake levels really went down because they were diverting water for farming so fish had no water to spawn in.”
The story of Pyramid Lake and its inhabitants, however, is one of survival, against all odds.
After a long struggle involving numerous court actions, the Pyramid Lake Paiute Tribe was able to negotiate water allocations with the federal government and protect the lake and fish under the Endangered Species Act of 1967 and the renewal of the Clean Water Act of 1987.
With more water discharged into Pyramid Lake through the Truckee River, lake levels have since stabilized and salinity levels have stopped increasing. Lahontan cutthroat trout have been successfully reintroduced into Pyramid Lake and the Cui-ui have been found migrating to their spawning grounds in the Truckee River as they did decades ago.
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