Effect of Heavy Metal Pollutants on Fish Population in two Egyptian Lakes

Heavy metals pollutants are dangerous for the environment. Some of these are essential elements that are required for the normal metabolism of the body such as copper (Cu), iron (Fe) and zinc (Zn), while others are non-essential and play no significant role such asCr),lead (Pb) and cadmium (Cd). Their natural effects can be toxic, carcinogenic, mutagenic or teratogenic. This study investigated and compared the relationship between the concentration of chromium (Cr),lead (Pb) and cadmium (Cd) in Lake Bardawiland Lake Manzalah(Egypt)on fish population. Moreover, the study also investigated the effect of theheavy metals on reproduction and growth ability of thinlipped grey mullet (Liza ramada) and the sea bass (Dicentrarchuslabrax. Histopathological and histochemical examination of the gonads (testes and ovaries) of the two fish species was conducted and length-weight relationships were studied for both male and female members.The study demonstrated that toxic heavy metals can alter tissue histological structures and cause reproductive defects.