Dear Friends:

Jacky Foo asked:
> Q: is this a common survival rate of grasscarp (100 %) or was it a special
> case in the manure-fed pond where survival was low (50%) for some reasons,
> if known.

> Q: is the survival of Tilipia, Crucian carp, common carp and Bream usually
> 100 % ? Since aeration is provided for the ponds, are there any other
> factors that you ensured in order to have good survival of the fingerlings
> ? Do you have any predation by birds ?

The parasite eggs and pathogen will be killed after anaerobic fermentation.
According to analysis, the extinct rate of fecal coliform Bacillus reached 98%
and of the eggs of hookworm reached 99%. So the fish diseases in slurry loaded
pond must be less than in manure loaded pond, and the survival rate must be higher.

The grass carp fingerlings stocked in slurry pond was 20-30 grams each
while 100 grams each in manure loaded pond. As is well known, grass carp
fingerlings do not feed on grass until they grow above 9 cm body length, and
they feed on plankton at the early stage of growth. That's why no grass was put
into slurry pond while small amount of grass put in manure loaded pond.
However, the number of two is too less to explain the real situation, I think.
In general, the survival rate depends on many conditions including
physico-chemical and biological conditions as well as seeds, feeds, management, etc.

In fishponds near a dense populated city, there will be no predatory by birds,
but we have to guard birds and other animals to feed on fish.