re: Truckee river (CA not NV)
Wow sorry to hear about that, we have had multi-fish days at Davis numerous times both wading from shore and from the boat (north east side of the lake - PM me for specifics if you want). I hear the blood midges are starting to hatch as well as the damsels. Hope you have better luck next weekend, I am gonna sneak up early tomorrow morning with the boat and see if I can get a few hours in. The wind does tend to pick up between 11 am and 1 pm usually so early is most of the time the best time to get out. We have had a very windy year this year, hopefully it will calm down a bit as the warmer weather starts to take hold. Looks like it is gonna be 3 or 4 weeks before the river really calms down and gets back to a decent flow.
Here is an email I recieved form CA Fish and Game on the lice:
We are aware of the situation at Lake Davis. We examined a number of trout from Lake Davis to confirm the identity the organisms being seen. We found light to heavy numbers of copepods on the fish. The majority of the fish lice we observed were of the genus Salmincola. There may be a few of the genus Lernaea as well.
Common names for these copepods are “anchor worm, fish maggot” etc. The organisms found on these particular fish are commonly found in waters throughout the western United States. This organism usually does not affect fish health, though its appearance on fish can be
unattractive. The presence of this organism on fish does not render
the fish unfit for human consumption. It is not an internal parasite, but rather infects the gills, fins and flanks of susceptible species of fish. There are no practical treatment options available for lakes and reservoirs.
The increased numbers of these organisms being seen this year is most likely due the warming of the water and the high number of fish planted into Lake Davis. The organisms were already in Lake Davis. When Fish and Game planted the large number of trout into the lake we provided a large number of hosts for the parasite to live on and multiply from.
The copepod numbers will decline with cooling water temperatures and decreasing fish numbers.