Coppernose Die off

[Larry Penland]

Ive had brim die offs before columeris,from over crowding, and early Spring  warm up,followed by a cold snap, forcing the brim off the beds, then back on. These are unavoidable, and accepted. But has anyone lost their Coppernose, after having the pond freeze over? Its not the first time that Spring brought a lack of numbers in the Coppernose population, and may not be related. It seems to me that Winter die off is all to real with these Florida brim. When they die in Spring, they float, and are usable if you can net them in time. But the Winter die offs just leave me scratching my head as to where they went. My pond is about 3 acres and 20 ft deep at the deepest. All I can figure is that the warmer lower oxygen bearing water, rolled over under the ice. taking the oxygenated water to the bottom. the warmer water "unable to oxygenate"  by the wind flowing over it, because of the ice. suffocated the bigger brim. Which sank to the bottom. I don't know, and cant proove a thing! I believe I am going to add shell crackers this Spring, to have a more reliable and sustainable species in the pond. Any comments, thoughts or suggestions will be greatly appreciated. Thanks for your help,Larry Penland

[Tony Livingston]

Larry, Coppernose BG are not usually considered cold hardy.... they do not tolerate cold water very well, especially when it's severe enough to freeze over.

Have you lost any other species of fish besides the BG? That might indicate a low DO event, also common under the ice, conditions permitting. If the Coppers are the only mortalities, then I would bet their demise is temp. related.

[Larry Penland]

You know Tony, I have had a problem with my bass reproducing ever since Katrina, about 7 years ago. I don't know if they lost any numbers that winter or not, since "like I said"they never floated up where a man could see them. Its possible, is the best answer I can give to that question. I am assuming that it is probably a problem with my particular pond, because I have friends that say they feed some ponds around here with 2 1/2 lb coppernose right in the middel of the day. Mine have never gotten that big. I decided this summer to start fertilizing my pond to darken the water. not only to help hide the bass on their beds , but to help the water absorb more heat in the winter. But being as we are semitropical we have a dry season , in Sept. and Oct. when the water gets crystal clear. Hopefully next summer I can keep it blooming long enough to hold some more heat up into Winter.I don't know what else to try. I know they won't sell coppernose from her any further North than Tennessee, but we are 300 miles south of there.

[Tony Livingston]

You SHOULD be ok as far as water temps Larry....I suppose that  a group of fish could become regionally adapted to a certain range of water temps, and then succumb during a particularly bad cold spell, but I would expect your neighbors to suffer the same fate also.

If it is a water issue, then you should notice mortalities in other species as well.  Oftentimes a mort will not float, but I would still think you would notice a few LMB, or other fish floating along with the BG. Having your water tested would probably be my recommendation, preferably before adding any additional fish....find out where you stand water quality wise, and population wise.....then decide where adjustments need to be made.

[Walt Foreman]

Granted I'm not there in MS, Larry, but the picture of your pond is becoming a little clearer.  Largemouth struggle to reproduce successfully in ponds that are badly overpopulated with bluegill; this is widely documented in fisheries science, and I've seen it firsthand dozens if not hundreds of times.  It's pretty common in ponds with overpopulated bluegill for the bass to eventually become extinct - three of my best bluegill ponds were this way when I began managing them in the spring of 2009.  They were stuffed full of morbidly stunted bluegill; the pond in the "best" shape featured bluegill that averaged about four inches, and in the worst pond they averaged two inches long and their eyes were the biggest feature on their body.  There were no largemouth left in any of the three ponds, nothing but hordes of tiny bluegill.

I began stocking largemouth and other predators, and had to keep stocking predators for a couple years combined with treating the watermeal and duckweed and installing automatic feeders and feeding multiple times daily, but now those ponds are producing some giant bluegill.  

If your pond is badly overpopulated, you may not have been losing the big coppernose in the winter - what's more likely is that you've never had big coppernose at all because they're so overcrowded that there's not enough food to go around and they're just not growing.  Even supplemental feeding multiple times a day can't compensate for severe overcrowding, which it sounds like you have.

You just need to stock adult (8-10" or larger) largemouth, and a lot of them.  Especially with a pond as big as yours, you may have to do two or three stockings over a couple years before you finally reach a density of predators that begins to thin out the bluegill so they can grow.  You might also think about stocking a handful of blue or flathead catfish in larger sizes (5-10 lbs. each) if you can source them, as they would immediately be able to eat the average size bluegill in the pond, whereas even a 10" largemouth would have to grow some before it reached a size where it could eat 4-5" bluegill, which sounds like it's the average size in your pond.  One of my best ponds now didn't begin to really turn the corner until I stocked five blue cats last summer that were 5-10 lbs. each; before the blue cats, even though I had stocked largemouth twice as well as two tiger muskie and 10 hybrid stripers, I would see hundreds of 2-4" bluegill every time I set the feeder off.  A year later, this past summer, the bluegill were averaging 8" and we caught a couple in the pound range, and those runts became the exception rather than the norm.  And, a bluegill that would go between a pound-and-a-half and two pounds, probably closer to two, was caught from a one-acre pond I manage that has dozens of flatheads and blues that the owner stocked several years ago from the Tennessee River.  That pond has a lot of bluegill that are starting to get in the pound-plus range.  

[Walt Foreman]

Water temps should not be an issue where you live, Larry - you're six hours and 4.3 degrees latitude south of me, and I've only had coppernose die off during the winter once, and that was a very shallow pond (six or seven feet at the deepest) in which they had just been stocked in October and had not had much time to acclimate to the pond.  I know of several ponds in my area that have had them for ten years or more and never had a winter die-off.

I suspect you have a water quality issue.  Does the pond have weedgrowth on it?  Certain types of aquatic vegetation, especially watermeal and duckweed, greatly reduce the oxygen levels in a pond and can cause fish kills; if you have one of these types of weed, your oxygen levels could be low enough that when you go into winter and there's less phytoplankton in the pond (ponds with watermeal or duckweed have low phytoplankton all year, which is why they get low in oxygen), all it takes is a little ice to stop photosynthesis altogether and you get a fish kill.  

Another factor: you mentioned that the bluegill are overcrowded.  They become more susceptible to disease, and are in general just weaker with their immune systems, when they're crowded, so that could be causing problems as well.  Stocking 150-200 8-10" largemouth would thin out the smaller bluegill and allow the remaining ones to grow much larger than they do now, and it would also provide for better conditions for the big bluegill during winter.

Especially with having water twenty feet deep, you should not be having winterkill problems.  I would venture that it's a water-quality issue.  You might think about installing a bottom-diffuser aeration system, as that would go a long way toward preventing future kills.

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[Tony Livingston]

You mentioned Katrina... by any chance did your pond wash over the dam, or at least discharge a LOT of excess water? If so, could you have lost your fish that way?