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JCO
04-17-2009, 10:51 AM
Take into consideration that this all happened about 4 years ago, but this is the sequence Codi and I went through.

Once we decided to make ago of it, it was time to get educated. I ordered a bunch of books and videos. We everything we could find on the Internet.

By far the best information came from Dr. James E Rakocy with his University of the Virgin Islands (UVI) System. While the rest of us have been having disasters, trying different things out, they have scientifically measured the effects of different ratios between plants, fish and grow bed size.

This link has everything – especially for those in the United States (fish, prawns, ponds, systems, etc).
http://srac.tamu.edu/

The core info I found here.
http://srac.tamu.edu under SRAC 430-43-; 4300-4399 -- General

This link contains a number of other good articles on re-circulating aquaculture.
http://srac.tamu.edu under SRAC 450-459; 4500-4599 – Re-circulating Systems

Initially I found that general guideline at MAXIMUM density of Tilapia was:
˝ lb of Fish per Gallon of Tank
2 Gallons of grow bed per Gallon of Tank
or in metric
250 grams of fish per 4 liters of Fish tank
and 8 liters of bed per 4 liters of fish tank

But if you read further, what you actually find is that the size of the grow beds/raft system at maximum density is tied to the amount of feed fed daily.

If you’re feeding a fish that grows slower, such as trout (9 month grow out with 1.1:1 feed conversion), then you have less feed input each day, so you need less grow beds.

Conversely if you’re feeding Tilapia at 1.7:1 and they grow out in 6 months, you need many more grow beds, or you must stock a lower density.

A 4 x 8 foot grow bed will remove 0.4lbs (+/- .2lbs) of feed per day (according to the UVI research). Using the UVI data, I found that a 250 gallon fish tank raising trout required 1.37 beds 4 x 8 feet (1.4 to 1 ratio), while the same system growing Tilapia requires 3 beds 4 x 8 (3 to 1 ratio).

That’s a big swing. In the end, the 2 to 1 ratio is a good average, especially if fish densities are kept below the maximum, or fish are started with fingerlings and the plant load grows as the fish grow.

So, we calculated the area of our greenhouse we were willing to dedicate to our initial aquaponics trial, and a 250-300 gallon (1000-1200 litre) fish tank with a 2:1 ratio to beds (1/2 gravel 1/2 floating raft) would work.

Choices of fish to raise:

Down South…no question, Tilapia is the answer and that’s what we went with.

Now for you folks up North:
1st Choice – Silver Perch (easy to raise, tolerate a wide range of conditions and grow fast, not prohibited in most northern states.
2nd Choice – Tilapia (similar, and easy to find in the U.S but will need heat in winter.
3rd Choice – Hybrid Stripped Bass (not as easy to raise, not as much info, but readily obtainable in the U.S.)

Next I looked at various system options, commercial kits, DIY systems, Barrelponics, Nelson and Pade, Aquaponics Made Easy, etc. I found that in the U.S. a packaged system was to expensive to even consider what with fish tanks costing $1 to $2 per gallon of tank. I found lots of recommendations to use 55 gallon plastic barrels, IBC Totes, Stock Tanks and More.

I finally wound up going with a 300 gallon rubber maid stock watering container, sturdy and no glass to break and they last forever...really :lol:
Hope this info help anyone who reads it. :mrgreen:

wolfracer
04-17-2009, 02:48 PM
Great links! This will take a while to dig through. Thanks again.

badflash
04-20-2009, 05:11 PM
DIY is definitely the way to go unless you are made out of money. One thing I've found with the rubbermaid tanks is that their quality control has dropped into freefall. Fine for outside, but a 1 Gallon per day leak is not acceptable for a basement system. 2 out of 8 of my tanks leak out the bottom from pin hole leaks.

As far as density goes, dissolved oxygen is the big limiter. Be sure to have a big airstone in each tank. If you push beyone 1/2 pound per gallon you need an oxygen concentrator, and that sort of defeats the purpose.

Something I'm also checking into is hybrid sunfish. Hybridized with bluegills these make all male hybrids that grow larger and faster than bluegills or sunfish. 2 years to market size, but no heat beyond freezing needed. The money comes from the produce, not the fish.

Eleven11
12-20-2011, 10:32 PM
I've been considering blue gills too. Have you found a source?

Its rather cold here in MD in the winter and I'm not sure if my rocket stove or solar water heater ideas will be effective for maintining water temps for tilapia.

I have been considering yellow perch too.



DIY is definitely the way to go unless you are made out of money. One thing I've found with the rubbermaid tanks is that their quality control has dropped into freefall. Fine for outside, but a 1 Gallon per day leak is not acceptable for a basement system. 2 out of 8 of my tanks leak out the bottom from pin hole leaks.

As far as density goes, dissolved oxygen is the big limiter. Be sure to have a big airstone in each tank. If you push beyone 1/2 pound per gallon you need an oxygen concentrator, and that sort of defeats the purpose.

Something I'm also checking into is hybrid sunfish. Hybridized with bluegills these make all male hybrids that grow larger and faster than bluegills or sunfish. 2 years to market size, but no heat beyond freezing needed. The money comes from the produce, not the fish.

foodchain
12-21-2011, 05:18 AM
The silver perch I am familiar with, aren't available in the US. Maybe we aren't talking the same perch. YP are typically what you see in the states.
Hybrid Striper bass are easy to raise, IF you have enough space. They need lots of water, and they don't reproduce. Each generation is "made" from a white bass and a striped bass. And incubated usually in a trough system or egg tumbler. Fingerlings are cheap though when bought in quantity. They are readily available in the South as many hatcheries will stock them for land owners stocking ponds. These guys get BIG.

davidstcldfl
12-21-2011, 06:07 PM
I'm going in the morning to pick up some catfish and blue gill from FL Fish Farms.
I wish they had speckled perch. That's some mighty fine eating...I think it's one of the better fresh water fish, swimming in FL waters.... :D

keith_r
12-22-2011, 07:05 AM
i saw "speckled perch" and thought wth is he talkin about?!? but a quick search revealed that it's crappie.. there are 2 distinct species, black and white.. also there is a hybrid with a racing stripe, i think it's called a magnolia crappie..crappie are often considered "pest" species in ponds because they spawn ealier than most other fish..
everything i've found shows that they're difficult to get on feed, but they are definitely some good eats..
srac and nrac do lots of studies on fish growth in different areas with different feeds..
ohio state has been doing yellow perch and bluegill studies for ages and has lots of info available online
i've also found that more recent work with bluegills shows that regular strains of bg can have as good as or better than growth of hybrid bg after the first year, it's mostly genetics (look up condello strain bluegill).. one of the main reason's hybrid bg were developed were to provide mostly male offspring so that the bg don't take over a pond/bow and become stunted

foodchain
12-22-2011, 11:13 AM
Crappie are all over down here....a lot of minorities crave them and fish for them in every standing ditch you can find water in. I have caught some, nothing to rave about in my opinion. Lots of tiny bones, irregular shaped fillets. Flavour is okay. Caught readily at the dam spillways.