Amber Mouser
Environmental Scientist Department of Fish and Wildlife
Brown trout (Salmo trutta) were initially introduced to Lake Davis during the 1970’s. During this decade, fisheries managers introduced many different species and age classes into Lake Davis with little success. After years of experimenting with the fishery, the California Department of Fish and Game (now Fish and Wildlife) (the Department) decided to manage Lake Davis as a “high cost, low yield trophy trout fishery.” This resulted in a 40,000 catchable-size (preferred Eagle Lake strain due to better survival and growth) rainbow trout (Oncorhynchus mykiss) allotment, and a limited brown trout planting program that was maintained to offer a diverse fishery (Powers 2003). In the Lake Davis post-treatment restocking plan, the Department stated “In addition to rainbow trout, brown trout adults (~3 pounds and greater) will be stocked in the reservoir.” (DFG 2007)
Currently, Lake Davis contains self-sustaining populations of rainbow trout, brown bullhead (Ameiurus nebulosus), largemouth bass (Micropterus salmoides), and robust populations of pumpkinseed (Lepomis gibbosus) and golden shiner (Notemigonus crysoleucas) (Mouser 2017). Brown trout are self-sustaining downstream of Lake Davis in Big Grizzly Creek (DWR 2017). Although brown trout have not shown up in CDFW lake surveys, anecdotal reports from anglers indicate that a small amount may be present in the reservoir. One brown trout was captured during this year’s ice fishing derby and a brown trout was the winner of the ice fishing derby a couple of years ago (Graham 2019).
Dietary studies from around the world indicate that brown trout, are opportunistic feeders that will consume anything from aquatic and terrestrial insects, crustaceans such as crawfish, with larger individuals feeding more extensively on fish (Calhoun 1966). An abundance of crawfish and golden shiner in Lake Davis presents an opportunity to convert the biomass from those species over to large brown trout.
Brown trout could eliminate part of a stunted population of trout and other species, and at the same time provide occasional larger fish to anglers in lakes overpopulated with other species of fish, particularly if the lakes are shallow and chemical treatment is not feasible (Wales 1946). In general, brown trout are more piscivorous than any other trout in hatchery inventory.
Another point to be considered is that brown trout tolerate temperatures from near freezing to over 80 degrees F (Embody 1922). The warm summer water temperatures also result in more prevalence of copepods. The main species of parasitic copepod (Salmincola californiensis) present at Lake Davis is not known to affect brown trout (Clifford 2019). Salmincola californiensis primarily infects salmonid fishes (Oncorhynchus spp.) (Kamerath et al 2009). They have primarily been reported on coho salmon (Oncorhynchus kisutch), sockeye salmon (Oncorhynchus nerka), pink salmon (Oncorhynchus gorbuscha), chum salmon (Oncorhynchus keta), chinook salmon (Oncorhynchus tshawytscha), rainbow trout (Oncorhynchus mykiss), and cutthroat trout (Oncorhynchus clarki). Also reported on dolly varden (Salvelinus malma), lake trout (Salvelinus namaycush), and mountain whitefish (Prosopium williamsoni) (Conley 2004). This ability to survive in warmer temperatures and resist the species of parasitic copepod currently found in Lake Davis makes them uniquely suited to survive summers in Lake Davis.
Lake Davis angling guides have stated that many of their clients express interest in targeting brown trout. Fishing guide Ed Dillard remarked that his clients are disappointed when they learn that there are no brown trout in Lake Davis (Dillard 2019). Another guide, Jon Baiocchi, only did ten trips to Lake Davis last year when he usually does 60-70. He stated that the majority of his clients are now going to the Truckee River instead and that “fly anglers like brown trout” (Baiocchi 2019). Angling guide Brian Roccucci stated that the brown trout that he caught in the past at Lake Davis were “always good quality” and also commented on how much the fly fishermen preferred brown trout (Roccucci 2019). Returning a brown trout allotment may increase the overall appeal of Lake Davis to anglers who have been turned off because of the post-treatment negative stigma.
In conclusion, Lake Davis should have a brown trout allotment based on the following points:
1). The Department stated in the Lake Davis EIR that we would restock with brown trout.
2). Brown trout are self-sustaining downstream in both Grizzly Creek and the Middle Fork Feather River (LaCoss & Rossi 2012).
3). Brown trout are likely already present in Lake Davis.
4). Brown trout will persist throughout Lake Davis’ temperature extremes.
5). Brown trout may resist copepod infestation in Lake Davis.
6). Brown trout in Lake Davis may provide a more aesthetically appealing fishing option for anglers who are dissuaded by the copepod presence on rainbow trout.
7). Brown trout may offer a late season fishing opportunity since they run in the fall.
8). Brown trout in Lake Davis may take fishing pressure off of other waters such as the Little Truckee.
9). Brown trout will help restore Lake Davis to be known as trophy trout fishery. They will promote the fishery without negative consequences and encourage tourism, possibly stimulating the local economy.
References
Baiocchi, Jon. 2019-03-04. Personal communication. Fly Fishing Guide. Biaocchi’s Troutfitters. 578 Sutton Way, Grass Valley, CA 95945
Calhoun, A. 1966. Inland fisheries management. California Department of Fish and Game.
Conley, David. 2004. 3.2.13 Gill Maggot Disease (Genus Salmincola). Institute of Parasitology. McGill University. MacDonald College. Quebec H9X 1C0 Canada
Clifford, Mark. 2019-03-04. Personal communication. Environmental Program Manager. California Department of Fish and Wildlife. Sacramento, CA.
Department of Fish and Game (DFG). 2007. Final Fisheries Management Plan For Lake Davis, Plumas County, California. California Department of Fish and Game, Rancho Cordova, CA. (Lake Davis Pike Eradication Project Final EIR/EIS. Appendix G.)
Department of Water Resources (DWR). 2017. Big Grizzly Creek raw data. Redding, CA.
Dillard, Ed. 2019-03-04. Personal communication. Fishing Guide. Dillard Guided Service, 209 Main Street, Beckwourth, CA 96129
Embody, G. C. 1922. Concerning high water temperature and trout. Amer. Fish. Soci., Trans., vol. 51, pp. 58-61.
Graham, Jeanne. 2019-03-04. Personal communication. Store Owner. J and J Grizzly Store and Camping Resort, 7552 Lake Davis Road, Portola, CA 96122
Kamerath, M., Allen, B.C., and Chandra, S. 2009. First Documentation of Salmincola californiensis in Lake Tahoe. CA-NV, USA. Western North American Naturalist 69(2). pp. 257-259
LaCoss, J. and A. Rossi. 2012. Lake Davis pike eradication: 2008 post-project monitoring. California Department of Fish and Game, Rancho Cordova, CA.
Mouser, A. 2017. Lake Davis pike eradication: 2016-2017 post-project monitoring. California
Department of Fish and Wildlife, Rancho Cordova, CA.
Powers, L. 2003. History of Lake Davis Fishery and Management. Lake Davis Pike Eradication Project Final EIR/EIS. Appendix G.
Roccucci, Brian. 2019-03-06. Personal communication. Fishing Guide. Big Daddy’s Guide Service, Po Box 557, Quincy, CA 95971
Wales, J. H. 1946. Castle Lake trout investigation. First phase: interrelationships of four species. Calif. Fish and Game, vol. 32, no. 3, pp. 109-143.
