SEASONAL VARIATIONS OF SOME BIOCHEMICAL PARAMETERS IN MUSCLES OF OREOCHROMIS NILOTICUS REARED IN LAKE MANZALAH FISH FARMS

SEASONAL VARIATIONS OF SOME BIOCHEMICAL PARAMETERS

IN MUSCLES OF OREOCHROMIS NILOTICUS REARED

IN LAKE MANZALAH FISH FARMS

BY
ABDALLA,A.E~SllEBLY*
*Nationallnstitute a/Oceanography and Fisheries
ABSTRACT
Six .fish farms were selected. 3 farms (1, 2 and 3) in the eastern region
ofLake Manzalah and 3 (4, 5 and 6) in the western region to represent the
different environmental variations within the lake. Seasonally water and
.fish samples were collected from the farms throughout the period from
autumn, 1999 to summer, 2000. Some biochemical studies ofNile Ti/apia,
o.niloticus, as water, fat, protein and heavy metals content (Zn, Cu, Fe,
Pb and Cd) concentrations have been determined in water and.fish flesh of
Oreochromis ni/oticus. The results of the present study show that, the
heavy metals concentration in the water was found in the follOWing order:
Zn (0.01D-0.020 mglL), Cu(0.013-0.063 mglL), Fe (0.1D-0.51 mglL)
Pb (0.14-1.07 mglL), Cd (0.010-0.-37 mglL).
Heavy metals concentrations in the muscle of o.niloticus followed the
order Zn(8.1 0-16. 30 mglkg), Cu(0.41-2.11 mglkg), Fe(20. 90-90. 00 mglkg),
Pb(2. 00-15. 30 mglkg), Cd(O. 27-0. 89mglkg). The heavy metals
concentrations in the .fish muscle were above the recommended standards
of the USEPA (1986) and the Egyptian laws that represent a potential
human health hazard.. .
The present results showed also high levels ofwater content ofmuscles
and accordingly low levels ofprotein and fats that reflect the negative
effect ofheavy metals pollution on the economic value of.fish and human
health.