Tagged Lahontan cutthroat trout released into Lake Tahoe allow anglers to help scientists monitor the threatened species

More than 15,000 Lahontan cutthroat trout are settling into their new Tahoe home after a release spanning the last couple of weeks. The Lahontan National Fish Hatchery Complex released the trout at Meeks Bay, Lake Forest Boat Ramp, and Sand Harbor State Park.

That is just the start of summer long stocking plans the complex has. Stocking will continue throughout the summer at various publicly accessible Tahoe locations in California and Nevada.

Despite having brown, rainbow and brook trout, the Lahontan cutthroat trout is actually Lake Tahoe’s only native trout species. The Nevada state fish is also the largest inland cutthroat trout in the world, growing up to four feet long and weighing up to 40 pounds.

The type of Lahontan cutthroat the complex released into the lake is known as the Pilot Peak strain. According to the U.S. Fish and Wildlife Service, this is a unique strain of Lahontan cutthroat trout that represents the original lake form evolving in the ancient Lake Lahontan.

In more recent historical times, this lake form existed in Tahoe, the Truckee River, Pyramid Lake and Walker Lake, but went locally extinct around the 1940s due to dam construction, invasive species, over-harvesting, human water consumption and changing precipitation regimes.

However, in the late 1970s, fish biologist Robert Behnke suspected he rediscovered the once thought lost species in Pilot Peak streams near the Nevada-Utah border. Genetic analysis advancements to confirm this suspicion wouldn’t develop until the 1990s.

That’s around the time biologist Mary Peacock at the University of Nevada, Reno, performed genetic analysis and compared the found Pilot Peak fish to museum samples of original Tahoe-Pyramid populations from the late 1800s and early 1900s. Through the resulting analysis, Peacock discovered the Pilot Peak strain as descendants of the original Lahontan cutthroat trout that once inhabited Lake Tahoe, the Truckee river and Pyramid Lake. A recovery program followed for the fish, reintroducing it throughout the Truckee River watershed.

But how did these Tahoe-Pyramid based fish wind up miles upon miles away? According to the University of Nevada, Reno, in the early 1900s before the Fish and Wildlife Services existed, a wildlife commission took small fish from Lake Tahoe and Pyramid Lake and placed them in streams across eastern Nevada and across the Utah border. Although many of those streams already had fish, the Pilot Peak streams did not, which is where the Lahontan cutthroat trout survived and was rediscovered nearly 100 years later.

The recent fish release is a part of a third year reintroduction and evaluation program at the lake. Hannah Moore with the U.S. Fish and Wildlife Service says the program is in its infancy, but seeks to understand the native species, a top predator, and how it can restore the native ecosystem in Lake Tahoe. Scientists are evaluating barriers to the species’ recovery through tracking, investigating habitat use, spawning use and predation, as well as tagging the fish.

About a quarter of the fish released over the last couple of weeks are suited with a T-bar anchor tag, having an unique ID and phone number. The complex wants to encourage anglers who catch these tagged fish to report the catch by calling that phone number.

This will help the U.S. Fish and Wildlife Service biologists evaluate the success of stocking as well as growth, survival and distribution of the threatened fish.

Other collaborating agencies include the Washoe Environmental Protection Department, California Department of Fish and Wildlife, Nevada Department of Wildlife, Tahoe Regional Planning Agency, U.S. Forest Service – Lake Tahoe Basin Management Unit, California State Parks, and Nevada State Parks.

Lahontan cutthroat trout are a threatened species under the Federal Endangered Species Act. The service is entering the second year of a program tracking how shallows shelves around the lake may provide vital habitat for their reintroduction as it may create a refuge away from Lake trout predation.

“We have much to learn,” Moore says, “and understand about LCT in their home waters of Lake Tahoe.”