You said "Don't you think it insensible to compare a pond whose food chain "is feed" to one that isn't?" My answer is no. The reason I say no is that this is an exercise to show the OP what the costs and stocking plan are for the proposed 2 ponds.
OK fine. But there is a very big difference. The feed converts directly ... something which in the beginning ... is good thing. But specifically it points to a different philosophy about pond stewardship. Your means of nourishing the fish will surely goose the front end growth of the fish. As I earlier pointed out to Polobby, feed is very efficient for growing fish. So I see your tack here, you hope to demonstrate that fish grown by your treatment will have a lower cost (maybe by fish or by pound). This may be true or we may all be surprised ... including myself ... that cost of growing fish extensively is cheaper when you don't. To really be a comparison, I can't be limited to 3 years. My focus is long term performance of fishing quality and water quality.
What you are trying to achieve is hyper-eutrophic conditions and standing weights. You have given no guidance on harvest. I presume that in 3 years you anticipate most of the 40 remain in the pond? If they averaged 2.5 lbs there would be 400 lbs/acre of just HSB. The standing weight of HBG would have to be much higher and there is no way to describe that situation other than the pond is becoming hyper-eutrophic in only 3 years. see below.
I was suggesting that he will use approximately 220# of food per year for his quarter acre pond. You say that there are 180 growing days per year there in Austin. If that is correct, then the OP can cut back on the feed to only use 132#/year, at a cost of $188/year.
Well then, it is worse than I thought, or maybe there is a typo? Please correct if there is a typo but I will work with your numbers.
OK so 132# per year is 528 lbs/acre year. It should convert at 2 to 1 and grow at least 264 lbs of fish each year by direct consumption and conversion. With no attrition, there would be 792 lbs/acre grown over 3 years. Add to this the pond's food chain and we may be talking close to 1000lbs/acre of fish. Dang, I respect your experience but I don't want that for my pond. I'd be at the limit of any kind of safety for my fish and on pins and needles every time a system of cloudy days came through.
And so up north you recommend 880 lbs of feed every year per acre? I am completely befuddled by that. Do your clients harvest 440 lbs of fish annually OR is this just what it takes to maintain 800+ lbs of fish in a pond that has no food chain? Dang. That question is not rhetorical. I'd like an explanation as to how nutrients at this level are being dealt with. Frankly, I think a lot of such feed is totally wasted. There is a good chance there is a lot of winter mortality in those ponds unless the fish grown are removed annually. Now keep in mind that the energy of any given meal is only 10% assimilated. The other 90% passes through the fish and accumulates in the pond.
Here is how I see 880 lbs of feed/acre. It is more than two tons of wet weight manure per acre OR a little over 8 55 gallon barrels of poo. What would say to your clients with excessive vegetation if they were adding 8 55 gallon barrels of poo in their 1 acre ponds every single year. Don't get me wrong, I am not trying to gross you out. But isn't that the net effect (after getting the growth) of feeding 880 lbs/acre every year?
