Dispersants are employed in oil spill situations to emulsify the oil into the water
column thereby, facilitating weathering; this is without consideration for aquatic
life and productivity. A renewal static bioassay was used to assess the recovery of
Oreochromis niloticus after exposure to water accommodated fraction of dispersed
Bonny Light crude oil (WAFDCO) and water accommodated fraction of Bonny
Light crude oil (WAFCO) at sub-lethal concentrations of 0.2, 0.4, 0.8 and 1.6ml/l,
based on the growth performance and condition factor after 49-days exposure and
54-days grow-out phases. The results showed that, the physicochemical parameters
of the test media were affected by the concentrations of WAFDCO and WAFCO.
The mean weight gain of O. niloticus increased with time in the exposure
regimes/concentrations. Growth performance was concentration dependent, the
highest mean weight of fish (15.67±0.78g) was from 1.6ml/l concentration of the
WAFCO, which was higher than the control. The mean relative growth rate was
higher (10.40±0.69%) in the fish from WAFCO while the highest mean specific
growth rate (0.85±0.05%) was from WAFDCO. The highest value (3.42) of
condition factor (K), was obtained in the 1.6ml/l of the WAFDCO. The K values
of the fish from the WAFDCO were slightly higher than those from the WAFCO,
which were lower than the control. Condition factor was greater than three which
implied that, the fish were in good state, thus, their recovery was good after removal
from the contaminated environment; hence, all mitigative actions should be prompt
during and after oil spills.