This study was carried out between May 2011 and February 2012 in order to determine the effect of environmental parameters on physical and chemical quality of water, fish condition as well as fish quality in Lake Edku. Fish condition; lengthweight relation, condition factor and hepatosomatic index of three cichlid species (O. niloticus, O. aureus and T. zillii) were studied. Also, fish quality as heavy metals accumulation and proximate body composition for muscle tissue of these species were estimated. Physico-chemical parameters were in normal ranges for fish culture and revealed that the lake water showed differences among different seasons. Concentrations of metals in fish muscles have been changed seasonally with higher values recorded during autumn and winter. However, these concentrations are still in the safety permissible levels for human consumption. The best condition and proximate body composition of fish were recorded in spring and winter seasons. According to the results of this study, the most important environmental parameters affecting water characteristics, fish condition and quality in Lake Edku were water temperature, nutrients and drainage water discharged into the lake.

Protein, carbohydrate, lipid, ash, chlorophyll (a; b , c and total chlorophyll), organic carbon and moisture contents of the macroalgae Ulva sp. (Chlorophyta) were studied in corresponding to the water nutrient concentrations in the different sites and seasonal variations over one year, 2012. The water and macroalgae samples were collected monthly from rocky and sandy sites, Ras Al-Tin (site A) and El-Muntazah (Site B) along 18.6 Km distance of Alexandria shore, Egypt. The results showed that the studied areas are rich in nutritive elements at high concentrations. As the chemical analysis elucidated that Ulva sp. powder was characterized by a high contents of protein (20.7-27.6% DW), lipid (8.7-15.75% DW), carbohydrates (42.31-51.37% DW) and moderate ash content (15.32-20.53% DW), with the peaks of lipid and minerals contents in winter, the peaks of carbohydrates contents in spring, peaks of organic carbon in summer and the peaks of protein and phosphorus contents in autumn. The high nutrients contents of Ulva sp. confirm the high nutrient storage capacity of Ulva in this area, indicating that, on one hand, it could be used as biofilters in the aquaculture systems and for bioremediation purpose. On the other hand, the proximate composition nominates Ulva to be exploited as a good food and energy resource for human; animals and in aquaculture. Also, it could be used in several industries such as food and cosmetics industries, for its high carbohydrate contents. Remarkable seasonal variations were recorded in the contents of the studied parameters in the Ulva samples. The N:P and C:P ratios indicated that these algae at the studied areas may experience phosphorus limitation in particular seasons during the annual cycle. Significant positive correlations were noticed between, carbon-nitrogen and carbon-phosphorus as well as between total chlorophyll and both of total phosphorus (P<0.05) and total chlorophyll (P<0.01).

Changes in heavy metals (Fe, Mn, Zn, Cu, Cd and Pb) concentrations in marine seaweed (green alga) Ulva sp. and seawater collected from the the Mediterranean Coast, Alexandria region, Egypt were investigated during monthly samplings from January to December 2012 to assess the spatial and seasonal variation of these elements as well as the pollutional status at this area. Fe had the highest concentration and Cd found the lowest one. There were statistically positive significant correlations among the levels of some metals in the macroalgae. The mean metals concentration in the Ulva tissue decreased in the order: Fe>Mn>Zn>Cu>Pb>Cd. Only, concentrations, Fe, Zn and Pb, in water showed significant (P<0.05) seasonal changes. Fe, Mn, Zn and Cu showed the greater spatial and temporal differences (P<0.05) in macroalgae tissues. The results showed that the studied area not faced heavy metals pollution. It is also concluded that Ulva sp. play an important role as a bioindicator for heavy metals contamination in seawater.