Endangered Lahontan cutthroat trout thriving in remote Nevada lake

RENO — A half-century after being added to the endangered species list, Lahontan cutthroat trout are thriving with help from a Native American tribe at a remote lake in Northern Nevada.

For nearly a decade, members of the Summit Lake Paiute Tribe and scientists at the Global Water Center at the University of Nevada, Reno have studied the robust Lahontan cutthroat trout population at Summit Lake, a small high-desert lake into which water flows in but not out.

The lake ecosystem has little human impact and could provide a model for recovery efforts in other lakes "that are less fortunate and that have lost their trout like the Walker and Tahoe," university researcher Sudeep Chandra told the Reno Gazette Journal.

The Lahontan cutthroat is Nevada's state fish and North America's largest freshwater native trout species. It was listed as endangered in 1970 and upgraded to threatened in 1975, according to the U.S. Fish and Wildlife Service.

The fish has crimson red-orange slash marks on the throat under the jaw and black spots over steel gray to olive green scales. It holds cultural significance for the Summit Lake tribe, whose name — "lake trout eaters" in the indigenous language — reflects the importance of the fish, said Rachael Youmans, tribal natural resources director.

The species is found in cold-water habitats in parts of Nevada, Oregon and California, including terminal lakes such as Pyramid and Walker; alpine lakes such as Tahoe; rivers such as the Humboldt, Carson, Walker and Truckee; and tributary streams.

The fish can grow to 50 inches and live for up to 14 years in lakes. River dwellers grow to about 10 inches and live less than five years. The species spawns between February and July, depending on stream flow, elevation and water temperature.

In 1844, there were 11 lake-dwelling populations of the trout, and 400 to 600 stream-dwelling populations that spanned more than 3,600 miles of waterways, according to the Fish and Wildlife Service.

Today, the fish are found in just five lakes and fewer than 130 streams in the Lahontan Basin in the northeast corner of Nevada, and several dozen streams outside the basin. Their habitat now covers less than 500 miles of waterways.

Declines have occurred due to water diversions, changing habitat and invasive species, Chandra said.

Summit Lake, about 140 miles north of Reno, is closed to non-tribal members, and fish catches are limited for members. The tribe erected grazing enclosures that prevent trampling from livestock and stopped diverting freshwater in streams for the reservation. Mahogany Creek flows into the lake unimpeded.

"It's a very healthy riparian corridor here now," Youmans told the Gazette Journal.

Summit Lake is mildly saline, and healthier than other terminal lakes in the huge Great Basin watershed of central Nevada, scientists say. Many terminal lakes have higher dissolved salt levels than lakes that flow to the sea.

Walker Lake in Nevada, also a terminal lake, has a salinity level of about 20 parts per thousand and is too saline for most fish, Chandra said. Summit Lake has less than 2 parts per thousand.