Pond Boss Forums INTRO Questions & Observations Thinking of taking a gamble with trout!

I've been growing out several species of trout in one pond so far running in about 41 gpms of aerated well water 24/7 in summer with good success. However the last time around my brook trout didn't do so well with the brown trout, and come to think of it I've seen them stressed before with brown trout in the pond. Teh rainbows and browns end up getting larger than teh brook trout over time also which can cause a problem. The brook trout seem to do better by themselves. Anyway, I'm thinking of leaving the brooks in one pond by themselves, and putting browns and rainbows in another pond that is downstream of this pond this spring. I can't easily and cheaply upgrade the well so I would have to either rotate the well flow 12 hours to one pond and 12 to the other (easily done with my plumbing) or split the flow in half continuously to each pond. (I'm leaning toward the 12 on 12 off flow.) Of course diffuser aeration would only occur at night when temps are low enough not to warm the water up.

From past experience surface water temps rarely go above 65 F. and never go above 68 F. during the hottest part of the summer when running the aerated well flow into one of the ponds. Not sure about the deeper water because I've never been able to measure it without a pier, but I would assume even with diffuser aeration at night mixing the water column, it should be a few degrees cooler than the surface water during the day.

I had this brain storm when looking at one of the ponds drained, and thinking I just can't see that deep and steep of a pond warming up much in 12 hours. I know ammonia (unionized and nitries) build up is another factor and I plan on monitoring that. Worse case scenario is a quick seine of one of the ponds and adding those fish to the other pond although it may be stressful to the fish.

Both 1/10th acre ponds are about 100,000 gallons, and in 12 hours 30 percent of the volume of the ponds are added and overflow.

Carrying capacity for one pond is about 12 lbs per gpm which comes to 491 lbs. That shouldn't be exceeded the first summer even for both ponds at the expected growth of the fish I want to plant. However I would like to grow them out another summer. Addtionally I would think the added substrate of both ponds combined should add more nitrification ability.

Thoughts?

Theo the Test Engineer talking:

It sounds like you've got a good, safe fallback position (return to all 3 species in one pond) for the first Summer if there isn't enough cooling for both ponds. So I think you've got to measure the heck out of those two ponds next year and see if it's going to work. Being able to measure the water temps over the whole depth may be needed, since you're going to be pushing the envelope closer to the safety limits. Can you just use a float tube or very small cheap boat to take temps over depth?

Am I correct that if you lost fish (say in the second Summer) you can still salvage them for taxidermy use if you get the trout close to death (on one side or the other) and freeze it?

Thanks Theo for your imput.

In answer to your questions I plan on having floating piers in place on both ponds. I've got the piers (stainless steel with vinyl decking that were given to me for free). I just need to order the foam billets to float them. I could install them with posts, but that would make thorough seining difficult for obvious reasons.

As far as salvaging the fish when they die... sometimes, sometimes not. Trout seem to more often sink to the bottom and decompose, or won't always float up when dead vs. others fish species. Not sure why, but it may be due to their densities and the slower decompostion and gas build up in cooler water. But I have salvaged some when I see they are severely stressed and they won't get better. Usually if they are severely stressed they will swim near the surface or hang close to the bank where they can be netted. Sometimes a weighted treble hook that snags them in the head does the job.

Thanks for your thoughts!

Have you done a cost analysis, such as figuring out potential monetary loss vs. potential monetary gain? That's usually how I approach things.

An example would be as follows:

Decision A costs $1,000 to implement and will result in a $4,000 loss of fish if it doesn't work.

This means I'm at risk $5,000 in the first year.

My potential profit, in addition to what I'm already making is $2,500.

This means relative risk to gain is 2:1

Then I calculate the odds of success. In this example, I would have to assume a 67% chance of success or greater to justify the project. If it looks like a 90% chance of success, then it's a no brainer. Pull the trigger.

CB1 - Consider getting a remote sensing thermometer from Menards or similar store. I bought several of them when on sale for $7.00 (reg price $15.00 Wireless Multizone Themometer - by Springfield Precisetemp, Springefield Precision Instruments). They have a remote sensing-sending unit that has an optional 10 long probe (included). This could be attached to your dock with the probe located in deep water and remote sensor affixed to the dock in a rain shelter to constantly monior your deep water temps. The unit sends a signal up to 100 open air feet to a base station unit. I have my probe in water 3' deep to constantly monitor the pond water surface temp by reading it on the base station in the house. A unit similar to this could constantly monitor the deep water temps and forewarn you that temps are rising to dangerous levels for maintaining healthy trout.

If the aerated water is constantly added at the bottom of the pond, it might provide a safe haven for the trout when upper layers of the pond start to warm up. As long as the thermocline was not disturbed due to a diffuser and the aerated well water held enough DO the bottom temps should be safe.

Another thought would be to use airlifts (http://www.aquaticeco.com/index.cfm/fuseaction/product.detail/iid/8723/cid/2157) to circulate bottom water to a covered pit that contained an aerator and then let the water sink back into the bottom part of the pond through another tube using convection. I think this would keep the thermocline intact.

I read a post on here that mentioned a farm pond in SC that had trout despite typical warm weather that was made possible because an irrigation pipe was run through the bottom of the pond. The pipe created cool water pockets to protect the trout.

Thanks everyone for you feedback. Looks like the pond will have to be used to produce perch fry now as my perch supplier is pessimistic about being able to export perch from Ohio into Indiana due the VHS scare. Additionally there has not been any progress from my state or Ohio in what is going to be required this spring. He has however agreed to answer some key questions on producing my own perch, including feed training them in the pond itself without removing them using light and a belt feeder outdoors.

Bender, what you are saying about not disturbing the theromocline to provide a cooler areated refuge below it makes sense in a recreational pond of trout that are not fed and not at a high density. However, with large amount of fish I am growing out there is a lot of feces and other metabolites that need to be broken down, and that requires aeration throughout the entire water columnn which a diffuser is best at. I try to keep warming down due to the mixing of the water column by turning on the diffusers only at night.

I also want the trout to come to the surface and feed on a daily basis and if the water was warm on the surface that might not happen.

Sounds interesting, does the light attract the fry and the belt feeder help keep the fry from being spooked by seeing a person feeding them?

I read an entry on YP at Wikipedia (http://en.wikipedia.org/wiki/Yellow_perch) that mentioned YP and European perch can cross breed. These cross breeds are supposed have excellent growth rates and grow much larger than YP or European Perch. I looked for someone who carries them but I could not find them. It might have something to do with European perch being on the nuisance fish list in MI.

Light attracts the fry and the belt feeder slowly puts feed out over an extended period of time which fingerlings need.

Here's a link to an article on it. (You'll have to scroll down to it.)

http://www.fws.gov/midwest/ashland/mtan/mtan_14.html


It is absolutely illegal to import exotic fish into the United States without the proper authorization. Not only because the species could cause problems, but they could also introduce exotic pathogens and parasites. I don't know of any state that allows the importation of European perch. Someone may be doing it but if they are they are probably breaking the law.

Thanks for the link. It was a great read and got me rethinking putting in underwater illumination. I wouldn’t want add the illumination and pull the fry away from safer areas to be devoured by predators.

The article I read said the University of Wisconsin was doing some joint research with a couple universities in Europe on the Perch Crosses. I don’t know if UW was able to import the European perch or if it was all done in Europe.

Either way I was wishing the European perch would have had invaded instead of the goby.