Q: You recently helped run an electroshocking program on Lake Tahoe where you were photographed holding a 24″ Koi fish; were you surprised at what you found?
Koi fish and other ornamental species are being found in the Tahoe Keys Marina area with some regularity, though that’s clearly the biggest Koi so far (we found it a home in a collector’s pond). A lot of species have been introduced into Lake Tahoe via fishtank or “bucket biology,” though the Koi don’t concern us as much as some of the other warmwater species like smallmouth bass, bluegills and catfish.
It’s part of the program; we’re partnering with DFG and UNReno to implement a two-year warm water invasive fish control project out of the near shore environment of Lake Tahoe.
What we’ve seen is intriguing; the migration patterns of cold water species vs. warm water species around the marinas seem to shift based on time of the year. Earlier in the year we were finding naturalized non-native trout species in the same areas where later in the summer warm water species like bass, bluegill and catfish dominate.
We expect to release the program’s first-year preliminary results sometime this winter.
Q: What’s your biggest concern with the warmwater invasives?
A: Warm water invasive fish prey on the native forage fish in Lake Tahoe. Recent studies by UNReno have demonstrated a steep decline in the lake’s native minnow species, probably due to warm water invasive species. In addition, research tells us the warmwater nonnatives have made their way to the far sides of the lake.
Q: I understand they’re reintroducing Lahontan Cutthroat into Lake Tahoe; how do non-native species affect the Lahontans?
Lahontan cutthroat trout — the only truly native Lake Tahoe trout — have been reintroduced to diversify the sportfishery in Lake Tahoe, where other trout species have been stocked for years. CalTrout helped provide funding to UNReno for a tagging program that will help track movement, depletion rates and learn more about the Lake ecology at Emerald Bay.
Non-natives like Lake Trout — of which there are a lot of — prey upon Lahontans, while warm water fish compete with and prey upon juvenile trout and native forage fish. Rainbow trout have also been stocked in Lake Tahoe and can hybridize Lahontans.
Q: Tell us more about CalTrout’s plans for Lahontan trout recovery?
CalTrout is working on a lot of projects, though I can highlight a couple here.
The first goal is to protect existing wild population; the only self-sustaining population of Lahontan Cutthroat trout in the Tahoe Basin resides in the Upper Truckee.
We’re trying to obtain a Wild & Scenic designation for the area, which will force the creation of a management plan.
Next year we plan to expand the presence of Lahontans in the Walker River Basin and other areas, and we’re funding the ongoing monitoring of Lahontan Cutthroat Trout at Independence Lake.
Finally, we’re garner more support for native trout protection and recovery — many members of the public are opposed to Lahontan Cutthroat Trout reintroduction because they don’t want to lose the naturalized fish species (Brookies’s, Brown’s & Rainbows).
There’s more going on, but those are the highlights.
Q: Good luck; we’d love to see those Lahontans back where they belong.
So would I.
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Peter Moyle is the Distinguished Professor Emeritus in the Department of Wildlife, Fish and Conservation Biology and Associate Director of the Center for Watershed Sciences, at UC Davis. He is author or co-author of more than 240 publications, including the definitive Inland Fishes of California (2002). He is co-author of the 2017 book, Floodplains: Processes and Management for Ecosystem Services. His research interests include conservation of aquatic species, habitats, and ecosystems, including salmon; ecology of fishes of the San Francisco Estuary; ecology of California stream fishes; impact of introduced aquatic organisms; and use of floodplains by fish.
Robert Lusardi is the California Trout/UC Davis Wild and Coldwater Fish Researcher focused on establishing the basis for long-term science specific to California Trout’s wild and coldwater fish initiatives. His work bridges the widening gap between academic science and applied conservation policy, ensuring that rapidly developing science informs conservation projects throughout California. Dr. Lusardi resides at the UC Davis Center for Watershed Sciences and works closely with Dr. Peter Moyle on numerous projects to help inform California Trout conservation policy. His recent research interests include Coho salmon on the Shasta River, the ecology of volcanic spring-fed rivers, inland trout conservation and management, and policy implications of trap and haul programs for anadromous fishes in California.
Patrick Samuel is the Conservation Program Coordinator for California Trout, a position he has held for almost two years, where he coordinates special research projects for California Trout, including the State of the Salmonids report. Prior to joining CalTrout, he worked with the Fisheries Leadership & Sustainability Forum, a non-profit that supports the eight federal regional fishery management councils around the country. Patrick got his start in fisheries as an undergraduate intern with NOAA Fisheries Protected Resources Division in Sacramento, and in his first field job as a crew member of the California Department of Fish & Wildlife’s Wild and Heritage Trout Program.