The Biology and Culture of Tilapias

Table 7. A feeding chart for the culture of tilapias in Israel (after Marek 1975). The daily feeding
rates are expressed in g/fish and % body weight.

Fish

weight

(g)

Daily feeding rates

For polyculture For monoculture

with carp

(9) (96) (g)

Fish

weight

(g)

Daily feeding rates

For polyculture For monoculture

with carp

(g) (%I (g)

@able 7). He considers that tilapia in polyculture gain some natural food

from association with common carp and other fish species and therefore the

amounts of supplementary food he recommends are somewhat lower than

for monoculture. In both cases higher rations are given when the tilapia are

small and the ration decreases with increase in body weight. Differences in

response of tilapia to supplementary food in polyculture and monoculture

were also found by Lovshin et al. (1977). In a polyculture pond the FCR

for tilapia and

-P""

combined was lower than that for tilapia done in a

monoculture. t was concluded that less feed was required to raise a given

biomass of hybrid tilapia and common carp than was needed to raise the

same biomass of hybrids cultured alone.

Conclusion

From this review it can be seen that very high yields of tilapia can be

obtained with relatively low inputs. This, however, requires complete control

of reproduction and the choice of proper methods according to existing

conditions. It is doubtful whether this can be done in small homestead

ponds, but with sufficient know-how it can be achieved in small or large

commercial ponds.

Discussion

HENDERSON: Can you give us some idea of the relative price structure for fish sold

from these pond culture systems? What percentage of the profit of the farm comes from

farming tilapias and what percentage from the other species?

HEPHER: I am afraid I cannot. Maybe Mr. Mires can help?

MIRES: On a national basis, we produce per year about 7,000 to 8,000 t of common

carp, about 1,000 t of silver carp and about 3,000 t of tilapias. The prices are: common

carp, about $2/kg; tilapias also about $2/kg and silver carp about $l.SO/kg. We also produce

about 700 to 800 t of mullet which fetches about $4/kg and miscellaneous specieg-grass