I sent off this letter to CADFG to see if we can get an answer to why the snails have died off in lake davis. Hopefully they are attempting to find an answer and solution. I will post their response when I receive it.
July 21, 2010
Amber S. Rossi
District Fisheries Biologist: Plumas/Sierra County
California Department of Fish and Game
P.O. Box 419
Quincy, CA 95971
Phone (530) 283-6864
Dear Amber Rossi,
I am writing to you as one of many concerned Lake Davis fly-fishermen regarding what appears to be the complete die off of the entire snail population in Lake Davis. Myself and others have noticed a steady yearly decline over the last 10+ or so years following the first rotenone treatment in 1997. Each year fewer and fewer snails could be found. Now they are nowhere to be found anywhere in the lake. Historically snails could easily be found floating in the water column from spring through the summer into fall any day of the fishing season. The population of snails was always quite massive as they are extremely prolific breeders. The snails provided an extremely important food source for the trout population especially in the fall prior to winter ice over when floating snails were eagerly eaten by hungry trout fattening themselves for winter survival. Aside from being a major food source for trout they also perform a variety of important functions such as cleaning the lake of dying plant and animal matter which in turn dramatically improves water quality.
Now they are nowhere to be found. Not a single one. I have looked all over the entire lake this year over a course of 18 days of fishing and have not been able to find a single snail of any type. If they are present they are not difficult to find as they regularly float to the surface and can be found in the water column, washed up along the many shallow points, clinging to weed beds, or floating on the surface all over the entire lake. Over the past many decades of flyfishing Lake Davis I would always see hundreds every day. I have spoken to dozens of other fly-fishermen this season and no one has been able to find or collect a single one. Last season there was a small remaining population in a cove across from Mosquito Slough. That last remaining population of snails are also now gone.
Snails have always existed in the area creeks and in Lake Davis and they are an extremely vital part of the fishery and now part of that environment is dying off if it hasn't entirely already died off. Snails dying off and the trout covered with various parasites seems to indicate a very serious problem with the lakes water quality.
Are any studies being conducted to determine why they are dying/died off?
I would like to know exactly what cadfg has been doing to determine why this important trout food source has died off?
I would also like to know what cadfg is doing to reestablish the snail population?
Sincerely,
A Concerned Lake Davis Fly Fisherman
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