The Biology and Culture of Tilapias

Table 2. Lower temperature limits (OC) recorded for Sarotherodon species.

Temperature

("(3 Comments Source

S. aureus

Survived in ponds when temperature

dropped for a short time

Survived in ponds when temperature

dropped for a short time

Survived this temperature for a short

time in laboratory

Died under experimental conditions

Began to die: previously acclimated

at 18OC for two weeks

Began to die: previously acclimated

at 28OC for two weeks

Higher survival when kept in 5%0

salinity than in fresh water (0.4%0)

Died: previously acclimated to 21°C

for 2 days. (Drop in temperature

0.8OC/l hour)

S. galilaeus

Survived in laboratory when exposed

to this temperature for a short time.

Lost equilibrium when exposed to

7.5OC for a short time.

S. mossambicus

Tolerated

Total mortality

Did not survive these temperatures

in fresh water; at ll°C, disorienta-

tion; survived ll°C in 5Xo salinity

S. niloticus

Determined experimentally

Determined experimentally

Yashouv (1960)

Chervinski (unpublished)

Yashouv (1960)

Sarig (1969)

Chervinski and Lahav (1976)

, ,

9,

Lee (1979)

Yashouv (1960)

Li et al. (1961)

Chimits (1957)

Kelly (1956)

Allanson et al. (1971)

Lee (1979)

Denzer (1968); Chervinski

and Lahav (1976)

Discussion

LOVSHIN: My experience of tilapias is that they do much better in waters with a high
pH. At pH 5 to 6 or below, they become sick and lethargic and do not grow very well.
Tilapias are found in the Zaiie Congo Basin anyway, where the pH of some tributaries
can get down to around 5; tilapias can live in waters of low pH, and I would like to