Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Fish Kill

My Uncle's 1.5 acre farm pond in NJ. No water feeding it except runoff and a spring that runs only in springtime. It does get hot but also does not lose much water due to nice clay soil. Built 25 years ago and stocked with LMB and BG and fine until 5 years ago. We had not fished it in many years so were not sure when the fish kill was but we only found BG and tons of frogs - no bass. We re-stocked with LMB, BG and also tried some variety with pumkinseed sunfish, GSF (and some pickerel that we never saw again).

Well, it happened again just this week - we saw tons of dead bass of all sizes down to 2 inches and BG/pumpkinseed in the shallows - and sadly 7 large LMB around 20 inches long. Probably due to long weeks of hot weather. We see tons of 1 inch YOY bluegill swimming in schools now with no fear (they would be slaughtered by 3 inch LMB and GSF in the past). We saw no living LMB and just a few 3-5 inch sunfish swimming around now.

I guess it is time to re-stock and hopefully this pond is not jinxed as it was fine for the first 20 years and now has had two fishkills in 5 years. I am sure just bad luck as there is no other issues we know of other than increasing geese populations in the last 10 years which are a pain (they eat all lilly pads and other things I have tried to get growing for YOY cover.

Also, I know low O2 kills the larger fish first but both of these fishkills completely wiped out the bass but left some sunfish. I assume the bass of all sizes are more susceptible than the sunfish.

Oldsconv,

Not necessarily. With D.O. problems the largest fish go first and many times the smaller fish are able to survive. Your largest fish were largemouths so...

Not sure how far upstate you are but did you recently have a sudden cool down, heavy thunderstorm, or even a hailstorm possibly? If your surface water is tepid it wouldn't take much lower temps to start mixing the water column.

Sounds like a turn over event to me as I've never seen largemouths not able to handle high temps. In fact when someone thinks hot weather has killed their warmwater fish I'm very skeptical.

If it was a turnover event, anoxic (low oxygen) water came up and pretty much wiped out the already moderate oxygen levels that occur in warm water.

If you don't want a repeat I would suggest some diffuser aeration to break up the water column and keep it mixed all summer.

Yes I agree with turnover versus too hot, but something that depleted the O2. No rain or storms, but it could have been a slightly cooler night one day after 95F temps for weeks that turned it over.

The weird thing is there were dead YOY Bass that were 2.5 inches and no evidence of any live bass at all but there are still live Sunfish up to 5 plus inches.

oldscov
Is your Pond Aerated? (as Cecil suggested)

Perhaps just cooler nights? My main pond has dropped 8 degrees in the last week. Lows air temps at night a few times were in the 50's to low 60's.



Someone else more knowlegable about species stress levels regarding D.O. levels may have to chime in, but it is possible largemouths as a species may have a lower threshold for oxygen depletion. For instance my smallmouth bass, although able to handle high temps, have a lower threshold for low D.O. levels. Different species have different thresholds.

Or it just may be where the small bass were in the water column when they were exposed to the anoxic water. Another possibility is the largemouth were already stressed due to a lack of sufficient or large enough zooplankton while the bluegills can subsist lower on the food chain. What I'm saying is it could be just about anything. Bluegill are very though as species. If you've got stunted bluegills they are even tougher as they'd been naturally selected out to survive austere conditions.

No aeration and I know that would help but people did have ponds for years with no aeration....and probably also had fishkills

Aeration is not really feasible due to location from the barns unless they make solar ones (like the solar things that charge a car battery?).

Pond was originally 14 feet deep in the deep end and is now around 12 based on testing.

My uncle said today the turkey vultures are having a field day with all the dead fish I pulled out and put on the banks.

There are both solar and wind powered aerators. I believe if you look at the advertisers here you will find dealers.

http://www.pondboss.com/resourceguide.html

How far is the pond from electricity?

Probably about 2000 feet from electricity.

Dang. I know a guy that ran 900' of air line to his pond.

Having experienced a fishkill a couple years ago, a couple questions to aid in finding the source...
Did the water color change?
Do you fertilize it?(the geese maybe)

As a matter of fact my cousin said it turned murky brown a couple weeks back which is only normal when we have rain (which runs into the pond via swales in the fields. However, there was no rain, so maybe the color change was the water turning over or from the geese crap.

We don't do any fertilizing - only maybe 4 years ago, we added a little fertilizer and lime since the water is very soft.

An algae bloom crash will cause a water color change and a fish kill.