Hello there
In aerated production ponds, tilapia are usually stocked at 9,500 to
19,500 fish per hectare or 4,000 to 8000 fish per acre. In final
grow-out production, stocking densities for 60-100 g (roughly a
quarter pound or slightly less) tilapia range from 250 to 400 fish per
cubic meter.
The estimated time to raise tilapia from egg to food-size fish ( with
food size averaging one - one and a half pounds) is highly variable,
but is usually in a range between 6 and 12 months. This growth period
reflects offspring from standard unimproved stocks. More improved
stocks do much better as you will find later.
So based on these rather simple figures, a half acre pond, approx 3-4
feet deep and using the lower fish population density, could produce
2000 lbs of food size fish per year, possibly twice that by using the
upper limits.
However, figures can go much higher than that. Some of the newer
farmed breeds of tilapia reach a harvest size of 800 grams (1.75 lb.)
after a growth period of five to six months, permitting about two
harvests per year. "In on-farm trials, a new strain developed by
ICLARM and partners grew on the average 60 percent faster than present
farm breeds, and their survival rate was almost 50 percent better.
With this growth rate, three crops per year are possible." - From
World Bank - "From "Hunting" to Farming Fish - Rapid Production
Increases Are Possible"
So once again using the figures I used in my first estimate of 2000
pounds per year, with the introduction of newer breeds, the production
could go to 6000 pounds per year with three different harvests. Or if
the upper fish populations are used, as much as 18,000 pounds per
year, feeding not only the village but providing extra to sell on the
market.
A well managed aerated pond as small as one quarter acre could feed a
village of 4000, let alone a village of 40. Now while that is larger
than a back yard swimming pool, it produces a lot of fish in a small
area.
So for your figure of 1,500 pounds per year, with a half acre
producing 6000 pounds at the lower fish population level, an eighth of
an acre, well managed and aerated, would provide what you want. Not
too much larger than that back yard swimming pool.
Search - google
Terms - fish farming, talapia farming, african fish farming
websites used in the above:
http://www.worldbank.org/html/cgiar/press/fish.html - World Bank -
"From "Hunting" to Farming Fish - Rapid Production Increases Are
Possible"
http://www.ag.auburn.edu/icaae/pub28.htm - "Review of Aquaculture
Development Activites in Central And West Africa" This website gives
some of the downside of African fish farming. The downside has little
to do with the production of the farm in terms of quantity, but with
poor management and the desire to sell the fish as a "cash crop"
rather than using it as a local food source. That aspect of things is
beyond whether an organization establishes a fish farm for a village
which in reality can produce enough food for the village, into the
realm of education about what to do with the product after it is
created.
http://www.da.gov.ph/tips/tilapia/freshwater1.html - Tilapia Raising -
Tilapia freshwater fishpond
http://www.cherrysnapper.com/cultivat.htm - "The cultivation of
tilapia" - you will find some amazing production figures, some of
which deal with African fiah farms as small as one fourtieth of an
acre. - "A case has been recorded of 150 adult Tilapias producing
15,000 fry in less than four months and another case is know in which
14 fish became 14,000 in only two and a half months."
If I may clarify anything before rating the answer, please ask.
Cheers
Digsalot |
