Thread: What would cause thousands of Asian carp to die all at once

lack of O2 could cause a massive die off

There have been several massive die-offs of silver carp over the past several years. Lack of dissolved oxygen would cause a multi species fish kill so this wasn't the case. Here is the answer I got from our Fisheries Pathologist. So far the cause of the die-offs has been inconclussive, though there is some belief it may be a virus in the brain. Many agency are working to find a "silver bullet" that would only impact invasive carp, but as you can imagine this can be a very large can of worms. I hope this info helps. Mike "There have been die offs in thelast couple of years along the Missouri from Nebraska on down and in theMississippi along the MS state line. MS State got a sample that wasn’t internalsoup yet and got Lactococcus off the brain but not the internal organs. Whilethis can kill fish since there was only one sample it’s inconclusive.

There was a HUGE die off in theCumberland this spring and spotty die off in a couple of other spots in KY,which is probably where this thread comes from. Fresh samples were sent to bothKY State and Purdue and no virus or bacteria was found. I don’t know if theydid just cell culture or that and molecular. If only cell culture was done,it’s possible for a virus to be present and undetected. Many viruses are veryspecific to the cell line and some don’t even have cell lines that work sodetection is just molecular. It’s always tricky with a complete unknown.

On the thread the only response was lack of O2 which would be incorrectin this case particularly for the large number of a single species of fishfound dead over a very long stretch of the river. Some of the dead carp in theCumberland had gas bubble disease (probably those closer to the dam) butincrease O2 saturation doesn’t kill 500K fish for the same reasons as lack ofO2.