Bruce,
I am flattered that you and others have asked for my imput. If the truth be know much of what I have done has been trial and error and dumb luck, but I have learned some things along the way.
O.K. first some things I have learned about the herons...
Will they try to stand and feed off a floating island? Darn tootin they will! I've seen them spear fish off of one of my piers as soon as I went back into the house just after feeding time, and I've seen them stand on top of my floating cages looking for an easy meal before I was smart enough to put covers on the cages. They are very adaptable birds and evolved to get fish anyway they can. They can actually curl their feet around a 1 1/2 inch PVC cage frame, which of course is not hard to believe as they do perch in trees at night and during nesting time. And they have sharp claws for gripping.
[b]The steep banks work really well to discourage herons, but I did have one bird that was willing to stand precariously on a very steep bank (almost vertical) waiting to lunge at a fish. He was able to grasp some weeds to hold himself in place. He was willing to take a chance at a tumble to get at one of my nice juicy brook trout. So steep banks are not 100 precent failsafe. That said, steep banks in combination with simple stake lines around the pond and either an electric fence or just some heavy braided fishing line should do the trick. I prefer the braided line that is brightly colored so they get the message. I once freed a pigeon from monofilament line as it got it's wing tangled in it. I wasn't crazy about that. I think if it had been able to see the line better it would have not got into that mess.
As far as the islands I would think the only way to make them non heron friendly would be the staked lines as Bill mentioned. And lets just say they only use the islands as resting places. That would still mean their fecal matter could end up in the pond and don't forget all they have to do is tilt their heads down to allow parsites to enter the water.
And even though herons are a wading bird, and are said not to land in water they will do so if they realize the bottom is shallow enough for them to stand on. A colleague tells me she sees them landing in a nearby shallow river all the time. So you want to make your underwater banks steep and the water deep enough so they can't land in it.
Not sure if I'm crazy about the islands in such a small pond for aother reason. Sounds like they would be geese (what Bill Cody calls flying toilets) or duck magnets which would be O.K. in a bigger pond, but most likely these birds could bring in too many nutrients and bring in aquatic weeds, or even parasites. One pair of geese could make a mess on a pond that size.
If you want the pond as an observation pond is it possible the fish would naturally go under the islands where you can't see them?
Do you have an ospreys or bald eagles in the area? They could cause you problems too in a small pond especially with clear water. Again some staked lines across the top of the pond would discourage them if necessary.
Your water exchange rate would be more than my ponds. My trout pond(s)(the one I have now and the one I originally had) had and have an exchange rate of about 2/3's a day vs. your projected exchange rate of about 2.5 times per day. My water temp doesn't go above the mid 60's on the surface in the hottest part of the summer in the trout pond, and that is with no shade. Seems to me your pond might stay even cooler. Or due to it being shallower warm up a little? Sounds more like a trout pool to me but I could be wrong. If so, you could have up to about 120 pounds of trout in your pond based on a carrying capacity of 12 pounds per gpm of flow which is what I use. And of course they are fed pellets too. That's still a fun group of fish to have whether it's 120 one pounders, 60 two pounders. 30 four pounders, or 12 ten pounders. If you went the trout route I would start out with higher numbers of course, and gradally thin them down. Of course you will have some natural mortality. If you went the trout route I would also do some mixing of the water column at night and on cool days with a diffuser to aide in nutrient breakdown. Make the banks inside and under the water steep enough to keep cooling down, discourage the herons of course, and discourage racoons from nailng any fish. Trout are actually a no brainer as long as you get healthy fish, and the water stays cool and oxygenated and they get enough to eat but you don't overfeed them.
If you want to go with bluegills and perch I would either enlarge the pond and/or reduce the flow if full flow keeps the water too cool for them. You could adjust the flow into the pond depending on the time of year or divert some of it away from the pond at certain times of the year. I will be doing this this year with my second pond in the series. Early in the year when i want the water to warm up a little i will divert the trout pond inflow away from the pond. Later in the summer when the full trout pond flow keeps the water in the secound pond in the series the perfect mid 70's range I run it in full bore. Which brings me to another possible suggestion rather than screw around with trying to constantly adjust flows:
Have two ponds. One for coldwater fish and the second for coolwater fish like the perch, but the bluegill would do fine in low 70 degree water. It's actually possible the bluegill would live longer in the cooler water vs. the much warmer water where growth is faster. Cooler water holds more oxygen and serves as a safety net too.
To show you how little flow you need and how small earth ponds can be to grow out trout I'm going to see if I can find an article in a magazine with pics of a series of trout ponds that sure simply pits. I don't believe they have liners either.
Did I miss anything?
Last edited by Cecil Baird1; 02/25/08 10:32 PM.
