Thanks Mud for notifying me of this thread. This is not Koi Herpes virus, because that only effects common carp and koi, and no other fish species. Regarding the deaths below the dam, there isn't any good evidence that was a virus that caused it. My personal opinion is that nitrogen supersaturation below the dam may have played a part, or that a concentration of fish was sucked through the dam, or both. Silver carp do suffer mass death events, though, because there are so many of them together that they tend to get sick, just like masses of soldiers do if they don't take good cleanliness care, or a bunch of kids in a daycare. In animals, this is called an epizootic (like an epidemic, but animals). We haven't seen any particular pathogen yet that causes only silver carp death, although very often when silver carp suffer a major or minor epizootic it is almost all silver carp, in part because most of the fish are silver carp, and also because the silver carp school together and spread it amongst themselves. And not every fish species will be susceptible to whatever is killing the silver carp.
However, I guess there is always hope. If a fish biologist is going to do something useful from a fish in one of these fish kills, he or she will need a very very freshly dead fish, or even better one that is still alive but looking pretty bad when it is taken from the water.
It's possible but unlikely that I could identify the pathogen from just a picture. Most likely even a fish pathologist (and I am not one, but I've been around fish for my whole life, including fish farming, so I've seen and diagnosed fish disease before) would not be able to determine the pathogen without a very fresh fish. In the future, in these major outbreaks of only silver carp, if you can get a sick fish or two (preferably not shot but we'll take what we can get) and contact me right away, I'll see what I can do to get the fish to a DOI fish pathogen lab and get it tested. If there are other fish at all dead (and sometimes people only notice the silvers, because that's what's mostly there) probably not worth it. Also, take pictures while the fish is alive or very fresh, and include closeup pictures of any lesions or red spots, and also open or cut off an operculum (the flap that covers the gills) and take a good closeup picture of the gills while the fish is very fresh. Might also open the gut of a dying or very freshly dead fish and take a good closeup picture of that. But don't cut on any fish that you are actually going to send. In such a situation, I can give you a fedex number and pay for the overnight shipping. But I probably wouldn't have any way to get a shipping box or blue ice to you in time or to purchase one. For a fish that is to be sent, DO NOT FREEZE IT. Keep it on ice or in the refrigerator and ship with bags or bottles of ice or blue ice, preferably in a small cooler or Styrofoam box in a cardboard box. If you call me (I'll give mudfish and Mike Bommer my cell number so you could get it from them) and it seems worthwhile to take and ship some fish, I'll give you a fed ex number and if you use one of your own coolers I'll send it back or replace it.
