_
Poster-summaes.
403
water
flushing, manual labor, and sediment removal. At
ties of silver carps (25,000/ha of 10—20 g fish) and grass carps-(500/ha of
50 g fish) with traditional stocking
fed only chicken manure, effective control of weed€g algàe, and sediments
were
accomplished and yields of prawns were similar to control bonds that-did
not
contain fish. However control ponds with prawns
oxygen
depletions, sediment buildups, algal crashes, and weed ihfestations that requi—
red daily heavy water flushing and manual labor for weed removal by the let
week of
the.experiment. Excretion, grazing, and sediment resuSpension by thecarps
stimulated phytoplankton productivity in the polyéulture ponds, and led
to
lower quantities of total phosphorus and higher early—morning dissolved
oxygen concentrations. Addition of high densities of grâès carps also mobili—
zed fecal foods
to
the bottom of the ponds,-proViding food for the benthiC'
prawns.
A second experiment showed that grass
at SGC/ha could
substitute for as much as one—half of the commercial fèëd requirements of the
intehsively—stocked prawns. Some technological problems with this polyculture
are
the hazardous jumping of the silver carp making
cult, the large amount of labor needed in separating
and ÿfawns at ”
and
the low market value of the Chinese carÿsï‘
'
INTENSIVE POLYCULTURË OF COMMON CAR? (Cyprinu‘è b3rpîb
(Hypo—
phthalmichthys molitrix) and
FÆQAEÎÔŒtQ/t FÙ.shQ/LÂÉA RQ/S eah.ch
'
"
'
Intensive polyculture of common
and
ried out by intensive feeding with 602-pèllètS
at a pro—
tein level of 25%. The following fertilizàtiôn procedures were uSed : ]) early
spring treatment of dry ponds : organic fertilizers (2000 Kg/ha) and mineral,
fertilization (only superphosphate, 150 Kgfha); Z) fertilizatiqn
the
_
vegetation period (May to
at;_—15 and 30 days with: the
150 Kg/ha : 80 Kg/ha and 130 …Ké'/hä
Two*S‘tockm{à
patterns were tested.
The first one (in pond J,
h395
fish stocks
:
(
fish/ha)
,,
land one.—yearggblïaÎç—;1ÇÈ:buf£àlo:€(%Bñ‘1üEîîii
was
._Kg /ha' of ‘ standard cons u1ernfi”shr (C1+“
QËQÏQDD‘ËFgÏ‘, s1+93
'
700 g)
yield common carp
Second stocking
fish/ha, …s] : 1500
1300@flsh/haThe t0talyleldwas
;
(acl+ :— 850 g81+
? 550%)ataf00dcmersm“
_
ratio of 2.92. ;
_
'
OBSERVATIONS ON THELIFE :H—ÏSTORY :=0E THË
(CyprlnŒ3ä—EÊ) I—_N
RESERVOIRS. OE WESTERN
'
GRAN/WO
“”di‘E'ÎGUILLENHOPËIÈ,
—
DèpaÆmenÆa de
AUd07095’4708032V
Some aspects» of; th e
5°mmÈ’Ï‘
the third
reservoirs have
Îeservoirs
group (eutr0phic and
pf 750 ha’ànda volu—
(Margalef et al., 1976); Œhe Arrçeampo
R… hasza.surfacefothe surface is deep—
me
of 35.5 Hm3; the…average depth is 5.1“ and f;°-“1ïY
'd
fof 177.8
er
than 10 m. The Torrejon
of 1260 ÎÎ aÏed monthly using
Hmï3- ; the average
CO
%
Poster-summaes.
403
water
flushing, manual labor, and sediment removal. At
ties of silver carps (25,000/ha of 10—20 g fish) and grass carps-(500/ha of
50 g fish) with traditional stocking
fed only chicken manure, effective control of weed€g algàe, and sediments
were
accomplished and yields of prawns were similar to control bonds that-did
not
contain fish. However control ponds with prawns
oxygen
depletions, sediment buildups, algal crashes, and weed ihfestations that requi—
red daily heavy water flushing and manual labor for weed removal by the let
week of
the.experiment. Excretion, grazing, and sediment resuSpension by thecarps
stimulated phytoplankton productivity in the polyéulture ponds, and led
to
lower quantities of total phosphorus and higher early—morning dissolved
oxygen concentrations. Addition of high densities of grâès carps also mobili—
zed fecal foods
to
the bottom of the ponds,-proViding food for the benthiC'
prawns.
A second experiment showed that grass
at SGC/ha could
substitute for as much as one—half of the commercial fèëd requirements of the
intehsively—stocked prawns. Some technological problems with this polyculture
are
the hazardous jumping of the silver carp making
cult, the large amount of labor needed in separating
and ÿfawns at ”
and
the low market value of the Chinese carÿsï‘
'
INTENSIVE POLYCULTURË OF COMMON CAR? (Cyprinu‘è b3rpîb
(Hypo—
phthalmichthys molitrix) and
FÆQAEÎÔŒtQ/t FÙ.shQ/LÂÉA RQ/S eah.ch
'
"
'
Intensive polyculture of common
and
ried out by intensive feeding with 602-pèllètS
at a pro—
tein level of 25%. The following fertilizàtiôn procedures were uSed : ]) early
spring treatment of dry ponds : organic fertilizers (2000 Kg/ha) and mineral,
fertilization (only superphosphate, 150 Kgfha); Z) fertilizatiqn
the
_
vegetation period (May to
at;_—15 and 30 days with: the
150 Kg/ha : 80 Kg/ha and 130 …Ké'/hä
Two*S‘tockm{à
patterns were tested.
The first one (in pond J,
h395
fish stocks
:
(
fish/ha)
,,
land one.—yearggblïaÎç—;1ÇÈ:buf£àlo:€(%Bñ‘1üEîîii
was
._Kg /ha' of ‘ standard cons u1ernfi”shr (C1+“
QËQÏQDD‘ËFgÏ‘, s1+93
'
700 g)
yield common carp
Second stocking
fish/ha, …s] : 1500
1300@flsh/haThe t0talyleldwas
;
(acl+ :— 850 g81+
? 550%)ataf00dcmersm“
_
ratio of 2.92. ;
_
'
OBSERVATIONS ON THELIFE :H—ÏSTORY :=0E THË
(CyprlnŒ3ä—EÊ) I—_N
RESERVOIRS. OE WESTERN
'
GRAN/WO
“”di‘E'ÎGUILLENHOPËIÈ,
—
DèpaÆmenÆa de
AUd07095’4708032V
Some aspects» of; th e
5°mmÈ’Ï‘
the third
reservoirs have
Îeservoirs
group (eutr0phic and
pf 750 ha’ànda volu—
(Margalef et al., 1976); Œhe Arrçeampo
R… hasza.surfacefothe surface is deep—
me
of 35.5 Hm3; the…average depth is 5.1“ and f;°-“1ïY
'd
fof 177.8
er
than 10 m. The Torrejon
of 1260 ÎÎ aÏed monthly using
Hmï3- ; the average
CO
%