# Bluegill die off



## woolybugger3 (Sep 6, 2013)

I am wondering if anyone else has recently experienced a large fish kill affecting mainly hand-sized bluegills. I am a member of an organization that owns and manages a 5+ acre pond for family fishing enjoyment in northeast Ohio, (Wayne County). Last weekend there was a die off of several hundred fish, mainly larger bluegill. Soil and Water took samples of the water, and it did not test high for ammonia and oxygen was adequate. They even wondered about a viral infection since they had run into a similar event earlier in the day.

The pond is rather mature and does have a lot of weeds. It has some holes in excess of 15 feet, but probably averages 6-7 feet in depth. It does get a substantial amount of runoff from agricultural land.

Any insights are appreciated.

Thanks


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## Muddy (May 7, 2017)

Sorry to hear that. I have not had any die offs in my ponds(Central Ohio). Did you have any large rain events prior to the die off?


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## M.Magis (Apr 5, 2004)

There are a ton of possibilities. Bacterial, viral, fungus, and maybe the most likely, spawning stress. You can check the dead ones for any clues, sores, body condition, etc ...


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## woolybugger3 (Sep 6, 2013)

Muddy said:


> Sorry to hear that. I have not had any die offs in my ponds(Central Ohio). Did you have any large rain events prior to the die off?


Muddy,
We have had several significate rains. My first thought was agricultural runoff, but without elevated ammonia levels we do not have a "smoking gun".
Thanks for your input.


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## woolybugger3 (Sep 6, 2013)

M.Magis said:


> There are a ton of possibilities. Bacterial, viral, fungus, and maybe the most likely, spawning stress. You can check the dead ones for any clues, sores, body condition, etc ...


Nothing obvious. They have spawned without this kind of thing for many years. What would cause spawning stress?


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## Southernsaug (May 23, 2019)

My money is on chemical runoff from farm land. The fact they never found high ammonia levels doesn't surprise me. A water test should also have been for nitrates and nitrites. Ammonia may have been used up by the time they tested and disapated. It could be herbacides as well. Spawning stress claims a few but I have never seen a big die off from spawning. In a normal pond I wouldn't expect disease as water temperatures are still reletively low..


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## M.Magis (Apr 5, 2004)

Chance of a “chemical runoff” is almost zero. And theres too many reasons to even list.

Natural die offs are pretty common, and the fact its only one species and one particular size makes spawning stress a very likely culprit. Its not something that happens every year. Likely just a series of factors that all happened to take place at once. But the only way to know would be to have a biologist take a look and check both the water and dead fish. I don’t know where to find one, but I would think a hatchery could lead you in the right direction.


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## bountyhunter (Apr 28, 2004)

my ponds 30 years old, only water that gets in is rain and springs built this way . never had a fish kill. hope you figure it out.


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## Southernsaug (May 23, 2019)

M.Magis said:


> Chance of a “chemical runoff” is almost zero. And theres too many reasons to even list.
> 
> Natural die offs are pretty common, and the fact its only one species and one particular size makes spawning stress a very likely culprit. Its not something that happens every year. Likely just a series of factors that all happened to take place at once. But the only way to know would be to have a biologist take a look and check both the water and dead fish. I don’t know where to find one, but I would think a hatchery could lead you in the right direction.


I didn't see anything that said is was just one species, but the post did mention bluegills specifically. Maybe woolybugger3 can clear that up. It's too late now as time is of an essence in diagnoses. I actually chuckled at the virus theory, as a virus wouldn't break out in two locations at the same time and viral outbreaks would be a drawn out event, not a one time thing. What area of the state did this happen in? 

I investigated a lot of fish kills in my 30+ years in fisheries and it was rarely disease. Usually oxygen depletion, pollution or spawning stress. In most cases by the time we'd get the call too much time had passed and no diagnoses was possible. Rotten fish are hard to examine.


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## woolybugger3 (Sep 6, 2013)

I appreciate everyone's input. I still suspect it was something from run off. A nearby field had just been tilled and planted. So far there has not been another episode. Our farmer neighbors have it tough, and I wouldn't want to see them fined, but if it happens again, we will try to get the water tested more quickly. I do think we were likely too late to take action. If we do find out anything more, I will update the post.


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## basslovers (Apr 26, 2016)

Common causes of fish kills ‐ rain (heavy sustained), drought, algal bloom, lack of dissolved oxygen.

You mentioned rain. What rain preceeded the fish kill? How much, how long, etc.

How much time elapsed from identifying fish kill to when water samples were taken?

What condition were the deceased fish in - any fungus, sores, bleeding, etc?

Any other species or only bluegill?


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## woolybugger3 (Sep 6, 2013)

basslovers,
Thanks for your thoughts. We had had several heavy rains in the days preceding the kill. There is no residence at the pond, so it was at least 2-3 days before I discovered it, and another couple before the water was tested. There were no signs of sores or injury on the fish that I could see, but they were starting to get pretty ripe. Although a small number of bass, crappie, and little sunfish were killed, it was 95% hand-sized bluegill. I have been made aware of two other ponds that also experienced kills, one was in close proximity. Nothing significant has occurred since, but you can bet we are keeping a close eye on things. I still suspect some kind of chemical runoff, perhaps combined with already stressed fish, but we might never know for sure.


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## Ol' Whiskers (Aug 11, 2004)

any chance you experienced spray drift from some agricultural aircraft?


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## basslovers (Apr 26, 2016)

woolybugger3 said:


> basslovers,
> Thanks for your thoughts. We had had several heavy rains in the days preceding the kill. There is no residence at the pond, so it was at least 2-3 days before I discovered it, and another couple before the water was tested. There were no signs of sores or injury on the fish that I could see, but they were starting to get pretty ripe. Although a small number of bass, crappie, and little sunfish were killed, it was 95% hand-sized bluegill. I have been made aware of two other ponds that also experienced kills, one was in close proximity. Nothing significant has occurred since, but you can bet we are keeping a close eye on things. I still suspect some kind of chemical runoff, perhaps combined with already stressed fish, but we might never know for sure.


One common cause for fish kills is heavy rains. Especially if the heavy rains occur after a period of drought and or high temperatures. That influx of water causes the water with diasolved oxygen to turn over and fish suffocate. My money is on this (over chemical poisoning). Very common cause. You mentioned a few days of rain. Cloud cover plummets oxygen production in a pond. Those weeds/plants now consume instead of produce.

I might have missed it but what is surface area of pond? Is it predominantly a blue gill pond with jist a few bass, crappie, etc mixed in? What sizes were the non-blue gill fish?


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## Muddy (May 7, 2017)

I was thinking the same as bass lovers. I’ve heard of this happening on the Pondboss forum.


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