Li wrote:
>Table 2, The survival rates came from counting the number of fish.
>In slurry pond, the stocking number of Tilapia was 821, but the
>number of fish harvested was 9,080. Here a footnote was
>missing. It should add a symbol of ** to indicate that there
>were 8,259 fingerlings, which were self reproduced plus the
>stocked 821, and the total should be 9,080.

John Harris [jfhdally@agn.net.au] asked:
> Q1: After 202 days there where 8,259 Tilapia fingerlings in the slurry
> pond whereas the Manure pond had only adults. Are these fish
> normally so prolific this young?

Q1: Yes. If the fish stocked are winter fingerlings of Tilapia. Oreochromis
nilotica can grow from fry to adult in six months in Jiangsu Province and five
months in southern provinces and then they begin to reproduce.

> Q2: In your concluding remarks you speak of draining the ponds at harvest.
> Is harvesting of fish then all at once? or are traps or nets used over a longer period?

Q2: Not all at once. Some fish species will grow for two years or three years.
You know the maximum weight gain for silver carp and bighead carps comes in the
second year and the max weight gain for grass carp and black carp comes in the
third year. Thus, two to three year production cycle are generally adopted in
China. The key to increase fish yields is to shorten the production cycles via
early breeding, nurturing and stocking large-sized fingerlings, etc. (Please
see my paper "Fish Polyculture in China" the same book that I mentioned to you).

Cheers
Li Kangmin