Pond Boss Forums INTRO Questions & Observations Fish Kill,,,Assessing the damage and moving on

Here is my story.
Pond Location - South Louisiana
Size - 4 acres and 3 to 6 feet deep

Pond was drained and the banks were rebuilt to provide a 3' drop to eleminate previoulsy shallow areas that were 1 to 2'.

Pond was stocked as follows.
11/03 - 4000 bg, 400 channels
6/04 - 400 northern bass

Events.
7/04 - Floating Algae covers the pond
7/20 - Pond co-owner sprays algae w/Cutrine-Plus
8/8-14 - Unusual cool spell, algae was not effected by the spraying.
8/14 - Pond co-owner sprays algae w/Cutrine-Plus
8/17 - Pond turned green (like an algae bloom)
8/21 - Algae begins to die
8/29 - Fish in distress, not feeding
8/30-31 - Fish kill
9/1 - Kill seems to have stopped

Damage, this is what was counted;
Bream dead - 861, 3-5 inch
Catfish dead - 108, all 8-12 inch
Bass dead - 248

These are actual numbers counted to the best of our ability, I assume actual kill numbers to be higher. Bg and cats spawned this spring, many small catfish and some large are still seen in the pond. I will be out fishing over the next 2 days to see if we have any large bg and any bass at all. I also need to mention that we had caught bg larger than what was found dead and I need to find out how many are left from the spring and August spawn.

I beleive that too much vegetation was killed at one time causing an oxygen depletion, but the mystery to me is the seeming algea bloom that occured after we sprayed, this cut visibility way down and may have had a part in the algea dying and or the oxygen depletion when it died. My friend the algea is already comming back.

All thoughts, ideas and suggentions on what happened and what to do next are apreciated.

Thanks,

I feel for you. It's so frustrating to do everything correctly, then be rewarded with a kill.
The problem is related to your water. Planktonic algae is certainly an issue, as was treating too much algae in the first place.
But the answer may lie in something we don't obviously see.
Had your pond been fertilized? It sure seems as though there were/are too many nutrients being taken up by too many/too much plant mass.
While the after effects of the treatment may have caused the fish kill, it may not have been the problem.
Follow the nutrients, and you will find the problem.
Was the pond fertilized? Heavily fed? Lots of livestock feeding, wading, pooping? Other sources of nutrients? If so, that's the issue. If not, improper techniques for treating, and mis-reading the resulting plankton bloom are the problems.

Thanks for the reply,

I discussed the algea treatment today with my neighbor and he said that he had spot treated applying a total of 3 gals over a couple of days (app rate is 2.5 gals per acre) so it does appear that the treatment was not the problem.

The pond was fertilized this spring and there was no resulting bloom, I determined that we needed to lime the pond so no more fert. was applied.

There is no livestock in the area, betwen myself and my neighbor we throw about a gallon of feed per day, not much. There is no wading and pooping may be an issue because there is a lot of life in the pond.

The pond has tons of ditch minnows, thousands of tadpoles and even somehow (there is a river next to the pond) got mud cats in the pond which spawned in the spring.

We definately misread the algea bloom,we have a red film (algea) in a corner of the pond.

How common are fish kills in non-fertilized ponds?

Fish kills can easily occur in unfertilized ponds. Two main ways.

First way is from oxygen loss due to killing or death of too many weed/plants at one time and massive decay of the dead material consumes dissolved oxygen down to concentrations too low for fish to "breathe"/respire. Also involved in first way is plants not producing enough dissolved oxygen during the daylight (cloudy periods) to supply the fish with adequate DO during the dark period. Respiration exceeds oxygen production.

Second way. When a pond stratifies or forms two layers with warm water on top and colder water below, the oxygen will be depleated in the colder bottom layer. When the oxygen is depleated then hydrogen sulfide gas (HS) begins to build up in the cold layer. HS concentrations become higher as the stratified conditions persist. HS is very poisionous to fish because the HS readily moves through a fish' gills and very easily into the blood stream. In fact HS is much more soluable in water & blood than oxygen.

When a pond goes thru a fairly quick mid-summer inversion or turnover (usually due to weather conditons) then everything in the deep cold layer is "brought" up into the upper warm layer. If the water quality in the upper warm layer is degraded enough then -- FISH KILL.

The fish kill "usually" does not happen during the autumn turnover because the autumn turnover is a more gradual event and the two layers are slowly blended over several days or a week+. Also during autumn, the water is cooler and is able to "hold" more dissolved oxygen than during the warmer water of mid-summer. The upper warm layer can absorb or cleanse a certain amount of "bad" water from an inversion. Note --- many mid-summer turnovers are not complete turnovers and only a small percentage of the deep water is inverted and no fish kill occurs.

The number of fish that die due to a turnover is dependant on: 1. the degree or percentage of inversion, 2. the severity of the HS buildup, 3. the dissolved oxygen concentraion in the surface water, 4. the water temperature, 5. the volume ratio of deep cold water vs warm surface water, 6. the biologial oxygen demand (BOD) of the warm water layer, 7. species and sizes of fish present, 8..etc...

Partial fish kills due to mid-summer turnovers are common occurrence.

One red flag I just saw..."red" algae floating on top of the water. You may have been the unfortunate recipient of a toxic type of algae. It would be worth looking into. Contact Cody directly. He's a genius when it comes to identifying stuff like that.
Whaddayathink, Wild Bill?

The red algea had just shown up yesterday. It was not evident before the kill, could it have been there before? Currently there is not much.

There are several microscopic living things that can appear reddish that grow in and around water. Can't really say much unless I see it at high magnification.

What about moving forward from here. I fished yesterday evening and this morning for bg and caught a total of 3. I feal that there are not many bg at all in the pond should I restock bg also or just bass, I do not plan to add any catfish.

Thanks,