Pond Boss Forums INTRO Questions & Observations blue gill dieing

My pond about 5/8 acre 15ft deep in some spots,some 3ft spots, clear to 4ft about 30% weeds, very little algae.For the past month I find 2 or 3 bg floating every morning all large no small ones. This is really got me stumped. Any one got any ideas what might be going on.Thanks....btw...got one aireator running 24/7 since aug.1 my water is a lot warmer then last year.

Fish deaths are stress related. Figure out the stressor and you are well on your way to figuring out what is causing the deaths. Numerous factors and often combinations of factors can contribute to fish deaths. Sometimes it is difficult to determine exact causes.

Handling fish in hot weather during catch and release is esp hard on fish in warm water. Catch and Release deaths can occur two maybe three weeks after the initial stress.

Some of the largest, oldest bgill will die from stress of spawning season.

In older established ponds / lakes (greater than 7-10yrs) about 15-30 % of fish will die each year due to old age. This begins once the fish are at the top end of their life span. Most of these deaths are not visible from above the surface. Fish get old and die.

Overcrowded conditions and OR food shortages cause stress to shorten life spans.

Fish with internal parasites will usu die quicker than their healthier siblings.

Addition of Aquashade reduces food reserves in ponds.

Use of herbicides can reduce habitat were fish food is produced and where the organisms/critters live and thus food shortages develop. Eventually nature thins out the fish denisty to match the food supply.

Laws Of Nature thin out the weakest or most vulnerable fish often the oldest ones.

See the next important post.

Jimmy,

What kind of aeration are you using? Did you just start up a diffuser Aug 1? Did you gradually increase the duration or did you just start running it 24/7 from the get go? If so maybe you brought up some bad gases and your larger older fish are stressed albeit a delayed mortality?

Summer is not the time to be first time cranking up diffusion especially 24/7.

What kind of PH do you have? Do you have large dinurnal PH swings?

I'm using this old post to ask a question concerning stress to fish. My question keys off of Bill's comment noted above. "Overcrowded conditions .............. cause stress to shorten life spans."

One of my projects this year will involve the partial draining of my BG pond. Amendments to fish structure and the enlargement of the "slit collection pool" will be the focus projects.

The stream feeding this pond, in an average year, ceases flow around the beginning of June. During the summer months, it will produce a flow after a day of rain or a good thunderstorm. In a hot/dry summer, the pond has lost 10-12 inches from evaporation. Average depth of the pond is 10' and I would like to lower the level 4-5'. Hopefully the work to complete the projects would emcompass two days. If possible, I may try to seine some of the young BG while the water is down.

The timing of the project will center around my contractors schedule but lets take worse case and say the pond is drained in June, and does not return to full pool till the fall rains hit(september time frame). I'd like to hear opinions on what, if any, stress problems you guys think may occur with my fish during this time. The pond is 0.15 acres, with 80-90 7" BG, some young BG from last years spawn and a few LMB.


Russ

Russ how are you going to lower the water. It seems to me you will (may) have two major stressors , crowding and water quality. If you lower the water 4 feet and evaporation takes another 18 inches that is a high % of your water missing. I used 18 inches as an example that is not thought about often but Ed numerically pointed out in another thread and I discussed in a siphon drawdown thread. As the water goes down the basin from which it comes shrinks and you get exponentially less water and it comes out faster. Further in some cases (most) if you take the water off the to 3 feet that leaves bottom water that is not fertile or oxygenated unless you are aerating. If you have been aerating that may make up for the water quality questions. Bob also posted out the fact that as water evaporates the remaining water has a higher concentration of metals and other bad stuff. As a % that could be a factor even if aerating. Most drawdown as a management tool info I have seen suggests no more than 20% of the bottom exposed which I guess in an avg, pond may be 30% of the water. Unless your pond is a cube you may be close to 60% of your water or more.

Do you have a place to move some fish to so you can bring them back ?

Take a look at Bill's archive on Fish Kills as it has links on stressors and crowding.

http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=22;t=000038

Most of the crowding info is wrt aquaculture methods (high fish densities). How old is the pond (fish been in it )? As a general guide most ponds will reach carrying capacity in 2-3 years after fish introduction. Even at normal pond fish capacity (no or only supp. feeding) you will not be at aquaculture operation densities. If you can avoid DO/water quality problems you should have some fish left even with a several mth. drawdown. Depending on which other problem , if any, arise you may be able to treat the problem .

Thanks for the reply Eric. FYI, I will be using a trash pump to drain the pond. This pond has bottom diffusers which should address the water quality problem. Based on loss of water volume overcrowding might/would be a red flag. Of course I could also look at this as an opportunity for the LMB to clean up some of the BG spawn from last year.

I'm going to reread your links and give additional thought to how much water I should remove. Thanks again.

Russ

I came home from driving our semi over the road to find 140 dead and dying BG. Check out this thread http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=20;t=003668 and you will get a wealth of information that these wonderful people guided me with! My "stressor" turned out to be Merganzer fish ducks, the coyote of the bird family, along with the other fact mentioned above, in that I need to feed more and feed later in the year. I think you will find all the help I got exactly what you are looking for.