Polycuiäure in carp panda
271
Table
& FES—SH SPECÏES WHECI—i ARE USED IN
POLYCUI/ËURE
I… Herbivorous and detrivorous; Il. Zooplankton and benthos feeders;
HL
Piscivorous.
.
……
Species
Famibr
I.
Grass
carp
(Ctenopharyngodon idella)
Cyprinidae
Silver carp
(Hypophthalmichthys molitrix)
“
_
Bighead carp (Aristichthys nobiiis)
"
Mad carp
(Cirrhina moiitorelia)
"
—
Catla
(Catla catla)
“
Rohu
(Labeo rohita)
"
Mrigal (Cirrhinus mrigala)
"
’
Grey mullet (Mugil cephalus)
Nîugilidae
Mallet
(Mugil capito)
'
"
.
Tilapia (Sarotherodon) aurea
Cichlidaè
’l‘ilapia (Sarotherodon) gaülaea
"
Tilapia €Oreochromis)
mossambica
.
"
'
Tilapia.
Sarotherodon) nilotica
"
Tilapia‘ vulcani
"
Tilapia zilä
"
II.
Common carp
(Cyprinus carpio L.)
'
Cyprinidae
_
Black
carp
(l\"lyiopharyngodon piceus)
"
Tench
(Tinca tinca)
"
Crucian carp
(Carassius carassius)
"
Goidfish
(Carassius auratus)”
Golden ide
(Leuciscus idus)
"
Whitefish
(Coregonus Iavaretus)
Salmonidae
_
Peled
(Coregonus peled)
"
Steriet
ruthenus)
Acipenseridae
Bester
9
Huso huso :(
ci A… ruthenus)
"_
-
Paddiesh
(Polyodon spathvJa)
"
—
III.
Rainbow trout
(Salmo gairdneri)
Salmonidae
_
Northern pike (Esox lucius)
European c'atfish ( Silurus gianis)
Siluridae
Pika —- perch (Lucioperca iucioperca)
Percidae
Largemouth bass (Micropterus salmoides)
_Centrarchidae
Snakehead
(Ophiocephalus argus)
0phiocephaüdae
For better understanding of the above question it seems neces—
sary to remind the rules which govern carp production in monoculture.
As
seen
in Figure 1, as stock density increases yield increases until
teaching the point of maximum possible yield QMPYZ. After the _1}_Ë_Y_
is reached a further increase
of stock density causes yield to decre—
ase.
Therefore, from the ecological standpoint the true gain can
be
achieved under polycultural conditions when MPY of the carp in
p01Yculture
(Cg) is equall or greater than that in m‘onoculture
(MPY of Cg>MPY of Cm).
When
a
point of reference to the carp .MPY is not given, it is
hard to say whether stocking of accompanying fish results
in
additional gain. Because if the c'arp stocking density is lower then
271
Table
& FES—SH SPECÏES WHECI—i ARE USED IN
POLYCUI/ËURE
I… Herbivorous and detrivorous; Il. Zooplankton and benthos feeders;
HL
Piscivorous.
.
……
Species
Famibr
I.
Grass
carp
(Ctenopharyngodon idella)
Cyprinidae
Silver carp
(Hypophthalmichthys molitrix)
“
_
Bighead carp (Aristichthys nobiiis)
"
Mad carp
(Cirrhina moiitorelia)
"
—
Catla
(Catla catla)
“
Rohu
(Labeo rohita)
"
Mrigal (Cirrhinus mrigala)
"
’
Grey mullet (Mugil cephalus)
Nîugilidae
Mallet
(Mugil capito)
'
"
.
Tilapia (Sarotherodon) aurea
Cichlidaè
’l‘ilapia (Sarotherodon) gaülaea
"
Tilapia €Oreochromis)
mossambica
.
"
'
Tilapia.
Sarotherodon) nilotica
"
Tilapia‘ vulcani
"
Tilapia zilä
"
II.
Common carp
(Cyprinus carpio L.)
'
Cyprinidae
_
Black
carp
(l\"lyiopharyngodon piceus)
"
Tench
(Tinca tinca)
"
Crucian carp
(Carassius carassius)
"
Goidfish
(Carassius auratus)”
Golden ide
(Leuciscus idus)
"
Whitefish
(Coregonus Iavaretus)
Salmonidae
_
Peled
(Coregonus peled)
"
Steriet
ruthenus)
Acipenseridae
Bester
9
Huso huso :(
ci A… ruthenus)
"_
-
Paddiesh
(Polyodon spathvJa)
"
—
III.
Rainbow trout
(Salmo gairdneri)
Salmonidae
_
Northern pike (Esox lucius)
European c'atfish ( Silurus gianis)
Siluridae
Pika —- perch (Lucioperca iucioperca)
Percidae
Largemouth bass (Micropterus salmoides)
_Centrarchidae
Snakehead
(Ophiocephalus argus)
0phiocephaüdae
For better understanding of the above question it seems neces—
sary to remind the rules which govern carp production in monoculture.
As
seen
in Figure 1, as stock density increases yield increases until
teaching the point of maximum possible yield QMPYZ. After the _1}_Ë_Y_
is reached a further increase
of stock density causes yield to decre—
ase.
Therefore, from the ecological standpoint the true gain can
be
achieved under polycultural conditions when MPY of the carp in
p01Yculture
(Cg) is equall or greater than that in m‘onoculture
(MPY of Cg>MPY of Cm).
When
a
point of reference to the carp .MPY is not given, it is
hard to say whether stocking of accompanying fish results
in
additional gain. Because if the c'arp stocking density is lower then