When the first European settlers came to the Lahontan basin on the
east side of the Sierra Nevada, it was widely believed that the Lahontan
cutthroat trout (LCT)(oncorrhyncus clarki henshawi) was common throughout
3600 miles of river Systems in portions of California, Nevada and Oregon.
LCT also occupied over 334,000 acres of lake habitat in their historic
range. Introductions of nonnative trout, such as book, brown, lake and
rainbow, before the turn of the century have negatively impacted LCT through
competition and interbreeding (hybridization). Land use activities such
as timber harvest, agriculture, livestock grazing, mining and stream diversions
[editor would add urbanization] have contributed to degrade the quality
and quantity of habitat for LCT. LCT now occupy 0.4 percent of their
former lake habitat and 11 percent of the former stream habitat within
their native range.
Many of the stream forms of LCT occupy isolated stream segments of larger river systems with not chance for recolonization. Because these populations are fragmented into small isolated stream sections, biologists believe that these populations may be at a high risk for extinction. The LCT was listed by the US Fish & Wildlife Service as an endangered species in 1970. The listing was reclassified to the less restrictive threatened status in 1975 to expedite recovery and management efforts and authorize regulated anglmg.
In northern Califomia and western Nevada, LCT were thought to occupy approximately 360 miles of the Truckee River [Editor thinks this refers to the system with all its tributaries, including above Tahoe], 300 miles of the Carson River and 360 miles of the Walker River. At the turn of the l9th century Lake Tahoe and Pyramid Lake supported commercialand sport fisheries. Following the decline of LCT, the existing occupied habitat within these basins now totals only 28 miles in the headwater streams of northern California. LCT now occupy approximately 0.2 percent of their historic lake habitat in the Truckee River system. Selfsustaining populations of LCT are gone from Lake Tahoe, Cascade Lake, Fallen Leaf Lake and Donner Lake. Both Pyranud and Walker Lake LCT are sustained by hatchery stocking.
The Dept. Of Fish and Game (California=CDFG) is commined to restoring LCT populations and is working with the US Fish & Wildlife Service and land management agencies such as the Forest Service and the BLM toward the goal of recovering the species. Becaus.e trout have generally been stocked in virtually every strearn that can support fish in the northern Sierra Nevada, efforts to reintroduce LCT must start with the removal of non-native fish. The removal of non-native fish is accomplished by chemically treating the stream with a fish toxicant down to a natu~al or constructed fish barrier. (The author goes on to describe the use of rotenone to kill non-native species--a very controversial topic in California and elsewhere)
Once the stream is believed to be free of non-native fish, restocking LCT can begin. Generally fish are transplanted from donor streams within the stream basin to maintain the integrity of the fish stocks within the separate basins of the Truckee, Carson and Walker Rivers. Restocking generally is done for one to three years following removal of nonnatives. During the restocking period the stream is closed to angling to allow fish populations a chance to expand to self-sustaining levels.
The recovery of LCT has become controversial with some of the angling public because they see an old favorite fishing hole closed for several years. Reintroduction has also proved controversial for federal land management agencies and land users who must then consult with the US Fish & Wildlife Service to avoid "illegal take" of a federally threatened species.
[The author discusses several streams where restocking has occurred in California, but where brook trout are re-establishing.] It is not known whether some brook trout survived the chemical treatment or were illegally reintroduced by persons opposed to LCT.
The CDGF and the Tahoe Basin Management Unit of the Forest Service have proposed to staff a full time stream guard in one area to monitor the fishery and enforce special angling regulations.
In a side note, Nevada Division of Wildlife (NDOW) has conducted surveys on fisherman preference for types of trout in the river. Mark Warren, fisheries biolo~st and newly promoted to a new policy position said the 48 percent of Truckee River anglers had no preference among fish, however 29 percent of the survey respondents said they preferred brown trout, 14 percent preferred rainbows and 9 percent indicated LCT as their choice. That said, many anglers don't seem to care what kmd of fish they catch, just as long as they catch fish. NDOW has completed four annual surveys and more information will become available. And the US Fish & Wildlife Service is evaluating LCT recovery for the Truckee River. We hope this potential conflict between NDOW, fishermen and the USF&WS will be resolved.