Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Another fish kill story

I mentioned on a previous post my cousin up in Northern IL had a fairly significant fish kill due to a variety of factors...colder than normal winter with heavy snows, relatively shallow pond and lots of vegetation.

He sent me some pics of the damage:








He was estimating he pulled somewhere in the vicinity of 3-400 fish out of the pond that were either floating or frozen in the ice. No telling how many sank.

His big problem is that his pond is one in a chain that flows out of a federal wildlife preserve. Which is really neat, as he can catch darn near anything at all. But right now the pond is too shallow and he can't get 'permission' to dredge it out. Hence, fish kill.

Very unpleasant situation
I had a simlar feeling last spring when some of my fish died because they had chosen to spend winter in a ditch rather than deeper areas of the pond. I lost some fish but not that much.

What about aeration? If that pond isn't huge then it's an option. Sure, it needs some work and money but it's better than seeing the same every spring.

Believe it or not he already HAD aeration in this pond...just not enough apparently.

Or perhaps not done correctly?

That pond IS a catchall, isn't it? LMB, BG, NP, Common Carp and Bullheads is what I see in the pictures.

That's certainly possible...it was in place when he bought the property, running 24/7. It's a small system, one set of diffusers sitting at around 8 foot depth.

It really is...the BOW that feeds it is fairly large and varied. That's both cool and also frustrating, as there can be no such thing as management in this pond. His fish move in and out at will, and he's pretty much been told he can't do anything to prevent that.

I've already heard of 4 fish kills in central il.. I'm glad i contacted Ted i haven't found a dead fish even though in the day i called him theyre were some piping at the surface..

No more dead fish for me even though we had 5 weeks of snow covered ice!

So you didn't' have a fishkill? That's awesome!

Awesome!

Maybe I got a little ahead of myself did a thorough walk around today..
5- 6-8+ lb bass very large fish
1- Prized BG

Still better than a few years ago when the whole pond was littered with huge bass, BG, 4 huge grass carp i didn't even know exisisted..

Not sure if I had a fish kill due to the very muddy water, but I am not seeing floating fish. I am not sure if they may be in the shallows just below the surface.

Rah,

I would think you would have some floating fish. Let's hope you're good!

I appreciate your concern and encouragement! I wonder if lower water temps reduced the O2 consumption under the ice, but who knows?

Absolutely lower water temps will reduce oxygen consumption! 3 mg/l could be lethal in 70 degree water but survivable in 39 F.

I was thinking that bacteria in sediment may have been using less O2 as well, so the O2 stayed higher. I'll know more about the fish survival when the water clears. I have a wetland that is deeper than originally planned, and it has fish from flooding. The water in it is clear and there are dead fish everywhere, but this is to be expected. It was not intended for fish. It was a hoot fishing a few years back though, when it was full of some nice warmouth.

BGK....I'd call losing "4 huge Grass Carp", a blessing! Sorry to hear some of the other big ones didn't make it. Their demise could be due more to age than water conditions.

I took the whole loss as a blessing it's really what got me into pond management.. of course the grass carp kill was an added bonus.. I agree I think that age might of had something to do with it and possibly my water got real dirty there for awhile these fish have been dead for a long time..

CB1 noted - ""Absolutely lower water temps will reduce oxygen consumption! 3 mg/l could be lethal in 70 degree water but survivable in 39 F.""

The colder the water is under the ice I think many species can survive in water with 1ppm dissolved oxygen due to very low metabolism in the cold water very little oxygen is needed. However we also have to consider the innate oxygen requirement of each species. Some species tolerate lower DO than others. YP, pike, and GSF are three examples of those that tolerate low DO. Trout and HSB do not tolerate real low DO, although the water temperature does affect the minimum that will cause stress and death.

One of the main features with this is the lack of knowledge about minimal DO requirements of fish species at low temps of 39F down 32F. It is biologically reasonable to me that a fish requires less DO at 33F versus 39F-40F. There is not a lot of literature about this for many of the pond dwelling species to my knowledge. As an extreme example, Yellow perch are known to move in to anoxic water to briefly feed on invertebrates in the sediments.

And lake trout have been known to hunker down on the bottom and wait out low D.O. in Lake Simcoe, Canada where their habitat is marginal.