Help! Dying catfish!

[Fishingnerd33]

Well, the first issue has come up at the pond. Last Sunday I took a walk around the lake and saw half a dozen dead catfish. Figured it must have been stress from the winter, then today while working I saw another couple. One was close to shore so I tried to grab it and when I did it swam off just out of reach. It would kick a couple times then go on its side. Any ideas what would cause this? Virus perhaps?

We have seen bluegill fairly regularly in the pond and they are happy, healthy, and growing nicely.

Would it be possible to take a fish in to a biologist to find out what is causing the dying?

[Shorty]

I wouldn't worry about a handful of catfish dying, just chalk it up to natural mortality from something, most likely a virus or fungus since no other species are dying, it could even be delayed fishing mortality. If you had hundreds of dead fish then I would be concerned, at the moment I would just keep an eye on it.

[Fishingnerd33]

It's definitely not delayed fishing mortality, unless we have trespassers...none of us have fished the pond at all.

We also discovered a cormorant last night, that sucks. Do they commonly wound fish that would lead to the fish dying later? I know they are serious predators of the fish, but didn't know if they normally caught their prey and killed them right away or if they simply mortally wounded the fish only to come pick them up later once dead.

[Shorty]

Cormorants will swallow fish whole as soon as they catch it, if the fish escaped I doubt that it would be mortally wounded. I guess it's possible a sick comorant could regurgitate a fish or two after it's been swallowed.

[whitetips]

What "Shorty" said.

If it is only a handful of fish, don't even think twice about it. Keep in mind that in any population of fish, there may be as many as half or more of them that die every year; there are always fish that die of natural mortality no matter what.

And considering that it has been just catfish, that suggest some kind of disease and not a water quality or pollution problem.

No, even if you picked up a fish and paid to have it analyzed, you might not know for sure what killed it because once they are dead it is usually difficult to determine exactly what the problem might have been. Collecting stressed fish, before they are dead, and then properly preserving them could give you a better idea, but even if you did find out what disease or infection was killing them, there likely would not be a thing you could do about it.

Fish can get stressed in the spring coming out of the winter, especially with wild swings in the weather, and once they get stressed they are more susceptible to disease outbreaks. Those outbreaks seldom kill all of the fish and in fact may not kill enough to have a significant impact on the population. Once it runs its course the survivors will be none the worse for wear.

Keep an eye on it, but unless you see dozens, hundreds of dead fish, do not lose sleep over it.

Daryl Bauer
Fisheries Outreach Program Manager
Nebraska Game & Parks Commission
daryl.bauer@nebraska.gov
http://outdoornebraska.ne.gov/blogs/...d-backlashes//

[pumpnlead]

Good read, thanks daryl.