Egypt. J. Aqu. Res. http://hdl.handle.net/1834/1046 2013-05-18T01:43:48Z 2013-05-18T01:43:48Z Konsowa, A.H. http://hdl.handle.net/1834/1887 2012-05-18T21:10:50Z 2007-01-01T00:00:00Z

Title: Ecological studies on fish farms of el-fayoum depression (egypt) Authors: Konsowa, A.H. Abstract: This study was carried out at the fish farms of El-Fayioum province during 2003 farming season. They extend along the eastern bank of Lake Qarun. These farms derive its water and drainage wastes into Diar El-Berka Drain. pH values at the chosen farms ranged between 7.43 and 8.91 and its values are certainly optimum for fish culture. Salinity levels at fish farms adjacent to Lake Qarun (Goda 2, 9.5‰) are generally much higher than the other fishing ponds due to seepage from the lake water. The major nutrient concentrations (N & P) at the main feeder were much higher than the corresponding values at fish farms. Nitrogen concentrations that represented by NO2-N, NO3-N and NH4-N indicated the dominance of NH4-N over NO2-N and NO3-N at the selected fish farms (0.026, 0.091 & 0.59 mg/L respectively). Total organic phosphorus (TOP) concentrations at the chosen farms were much higher than the corresponding values of orthophosphate. The abundance of phytoplankton reached the climax during January and March (8746, 6937 x 104cell/L respectively), but showed a severe drop during September and October (59, 38 x 104cell/L respectively) at all farms under investigation. Oreochromis niloticus prefers diet on Navicula spp. and Cyclotella spp. from diatoms; Prorocentrum apora from dinoflagellates; Euglena spp. and Phacus caudatus from euglenoids and few species of green and blue green algae. So it should decreases supplementary foods at these farms during the abundance of phytoplankton items in spring and summer seasons. Fish production of these farms depends on intensive aquaculture in which the fishes are fed with external food supply. This kind of aquaculture can be changed to extensive production during spring and summer seasons.

2007-01-01T00:00:00Z Guendy, H.R. http://hdl.handle.net/1834/1903 2008-10-07T10:36:19Z 2007-01-01T00:00:00Z

Title: Ozone treatment of textile wastewater relevant to toxic effect elimination in marine environment Authors: Guendy, H.R. Abstract: Ozone is a powerful oxidizing agent. The reaction of ozone with organic compounds in aqueous media has achieved a variety of treatment goals. The advantage of ozonation over the other oxidants is that the degradable products of ozonation are generally non-toxic, its final products are CO2 and H2O, and also the residual O3 in the system changes in few minutes to O2 .Convential treatment of textile wastewater includes various combinations of biological (activated sludge), physical and chemical processes. The dyestuffs existed in these wastewater are highly structured organic molecules which are hardly break down biologically. Decolorization of two types of dyes, Direct Pink 3B and Reactive Violet SH- 2R, by ozonation in aqueous medium was studied in presence of some effective variables.These variables were: the rate of ozone generation, ozone dose, current, pH and the initial concentration of the wastewater. The total quantity of ozone generated is determined from the calibration curve of the ozoniser performance, while the unused ozone is determined from the titration of iodine liberated; the difference being the amount of ozone actually used in the reaction. It was found that 98% decolorization occur in few minutes. Data on time of ozonation, temperature and other chemical variables were discussed. This research proved its success as a method for treatment of wide concentration range from the dye wastewater (100-1000 ppm), so it overcomes the problems of textile wastewater treatment.

2007-01-01T00:00:00Z Ahdy, H.H.H. Abdallah, A.M. Tayel, F.T. http://hdl.handle.net/1834/1898 2008-11-04T10:48:37Z 2007-01-01T00:00:00Z

Title: Assessment of heavy metals and nonessential content of some edible and soft tissues Authors: Ahdy, H.H.H.; Abdallah, A.M.; Tayel, F.T. Abstract: The level concentrations of heavy metals (essential and nonessential) were measured in different marine biota including cephalopoda, bivalve, crustacean and fish. The results reveal that these organisms show more or less the same order of distribution for each of the metals studied. The average concentrations of heavy metals exhibited the following decreasing order: cephalopoda > bivalve > crustacean > fish. The levels of metals in all studied samples are still comparable to those in their corresponding in the Mediterranean Sea. K (98-181μg/g) and Ca (547-1472 μg/g) were present at the highest concentrations in all investigated samples. Octopus and Sepia do not follow the general pattern. The highest value of Metal Pollution Index (MPI) in cephalopod was recorded in octopus (9.55) followed by sepia (7.62). Among investigated bivalve, the highest values of MPI were recorded in Mactra coralline (2.87).

2007-01-01T00:00:00Z Al Sayes, A. Radwan, A. Shakweer, L. http://hdl.handle.net/1834/1906 2008-05-14T07:46:21Z 2007-01-01T00:00:00Z

Title: Impact of drainage water inflow on the environmental conditions and fishery resources of lake borollus Authors: Al Sayes, A.; Radwan, A.; Shakweer, L. Abstract: The brackish water lake Borollus occupies a central position at the north between the two branches of the Nile delta. This lake has a particular importance in the fish economy of Egypt. Therefore environmental and fisheries investigation was carried out at the lake during 2000–2002, where 15 stations covering the whole area of the lake were sampled. The present study points out that: 1. The water transparency of the lake is low where the average Secchi disc depth ranged between 21.14 cm and 43.89 cm. 2. The average water temperature attained its minimum in winter and ranged between 16.20 °C and 17.80 °C. The highest temperature was in summer where it ranged between 28.33 °C and 28.52 °C. 3. The recorded pH values indicate that the lake water was generally in the slightly alkaline side and optimum for fish to live in. 4. The eastern part of the lake exhibited higher chlorosity values comparing with the middle or western areas as a result of mixing with the penetrated sea water. 5. The whole water body of the lake is well oxygenated where the average values of dissolved oxygen ranged between 6.6 mg/L and 11.1 mg/L. 6. The most abundant species among the inorganic nitrogen compounds was the nitrates. The average concentrations of nitrates in the water of the lake ranged between 1.23 μ gat/L and 7.165 μ gat/L. 7. The isolines distribution of phosphates concentrations indicate that such concentrations were high at the south decreasing northwards. 8. The drainage water contributes in increasing silicates concentrations in the lake water. 9. The sharp decrease in chlorosity of the lake water during the last 30 years greatly contributed in changing the species composition of fish population in the lake. 10. The percentage weight of marine fish species in the experimental catch decreased from 15.99% in 1973 to 1.81% in 2002, where the most of marine fish species did not exist in the catch. 11. The percentage weight of Oreochromis niloticus increased from 19.70% in 1973 to 39.43% in 2002.

2007-01-01T00:00:00Z