In the present investigation, length-weight relationship, condition factor, age, growth, mortality, gonadosomatic index (GSI) and fecundity of tilapias (Bolti in Arabic): Oreochromis niloticus, from Shanawan drainage canal (SDC), Al-Minufiya Province, Egypt, were studied. This was carried out on 162 fish samples collected during the period from April 1992 to May 1993. Oreochromis niloticus was found to attain sexual maturity early (8-9 cm), was more fecund (1,234-3,893) and has high mortality rates (91% for males and 94% for females). A comparison of the various parameters of O. niloticus from SDC with those of other authors in different localities and times in Egypt revealed year-to-year and geographically significant differences in relation to variation in weight with length, condition factor, fecundity, growth and mortality rates. These differences were discussed and were found to be attributed to the effect of eutrophication and pollution on the growth, age and other biological aspects of O. niloticius. Multiple regression analysis showed that only female GSI correlated significantly with pesticides and heavy metals contamination.

Potable water is a necessity for safe and better quality. In Egypt, this is no exception, and consequently, this study investigated the physico-chemical properties of raw, and treated water in Shebin El-Kom Water Treatment Plant. As indicated, here in this study, a number of parameters, namely Ammonia, Nitrates, and Chlorides, were observed to occur in water after treatment. Furthermore, Chlorides, Iron, Nitrites, TDS, Mn, and Mg, might occur in treated water at certain times of the year. Those parameters proved to be indicator for physico-chemical characteristics. Accordingly, a recommendation is presented.

Bahr Shebeen canal (BSC) and Khadraweya canal (KHC) are two Nilotic canals, the first is less polluted and the second is polluted. Oreochromis niloticus is the major fish species in the Nile and its branches, and consequently, this study is carried out on their biological parameters are studied to investigate the effect of pollution in those habitats. These included: various parameters of growth, mortality, survival rates, stomach-somatic index, gonado-somatic index, and hepato-somatic index. It was found that there is a significant decline in those parameters in the fish of KHC, as compared to BSC, which could be tied to pollution in that canal.

This study was carried out during a period extending between February 2016 and January 2017 in both Damietta and Rosetta branches of the Nile. Water samples were collected at eight sampling sites; four at Damietta and the others at Rosetta branch so as to detect the variability of the protozoan organisms and evaluate some physico-chemical parameters. It was proved that the protozoan genera of Rosetta branch showed more diverse as compared with those of Damietta one ( 46 and 35 genera respectively). These organisms were belonging to three main phyla ; Sarcodina, Mastigophora and Ciliophora where the latter predominated the preceding two phyla at the various sampling sites in both river branches. Simultaneously, organic matter, ammonia and nitrates exhibited higher levels in Rosetta than Damietta, while phosphates, dissolved oxygen and p H behaved in an antagonistic manner at the different seasons. The abundance of the sewage protozoan organisms was higher in Rosetta branch relative to those of Damietta which could be attributed mostly to the illegal runoff of the sewage wastes from certain villages on Rosetta branch that consequently affect oxygen and organic matter contents at these stations. These unicellular organisms were influenced and proved to be statistically significant to a certain limit with water temperature, phosphate salts, ammonia and organic matter.Field studies on the protozoan distribution in Damietta and Rosetta branches of the River Nile, Egypt Table (1a) Different protozoan genera at Damietta and Rosetta branches of the Nile. Rosetta branch at El-Menofeyia Province (46 genera) Damietta branch at Kalubeyia and Dakhleyia Provinces (35 genera) Sarcodina Amoeba sp. and Actinophora spp. Mastigophora Euglena, Phacus, Volvox, Gonium, Chlamydomonas and Ceratium spp.

Pesticides are one of the pollutants threatening aquatic invertebrates living in the tributaries of the River Nile. So, the effect of the biofungicide, Trichoderma harzianum on the crayfish, Procambarus clarkii and its influence on electrophretic pattern of proteins and tissue pathology of gonads were studied. Different concentrations of T. harzianum (100, 50, 40, and 20%) were used. The potency of T. harzianum to genocide ranged from many hours (less than a day) with 100% concentration to 39 day of treated with 20% concentration. Electrophoretic analysis was done to compare protein patterns of muscles from control and treated animals with 20% T. harzianum. The result recorded decrease in protein density of males and females post exposure to T. harzianum after one week (this decrease was more in males than females). However, the protein density increased four weeks post exposure to T. harzianum (this increase was more in females than in males). T. harzianum caused some histobathological changes in testis after four weeks post exposure when compared to the control. The testis showed deformed architecture, some testicular acini showed incomplete fusion and others with elongated shape. On the other hand, the ovary exhibited severe damage in oogenetic pouch like detachment of ovarian epithelium, fusion between some oogenetic pouches, and necrosis in connective tissue. It can be concluded that, T. harzianum has deleterious effects on the proteins and gonads of P. clarkii that may lead to disturbance/decrease in productivity and even death to this organism and the surrounding environment.