Articles
http://hdl.handle.net/1834/1003
2024-03-28T08:32:47ZGrowth, mortalities and yield per recruit of the shrimp fish scad Alepes djedaba (Forskal) (F. Carangidae), from Abu Qir Bay, Eastern Alexandria, Egypt
http://hdl.handle.net/1834/4995
Growth, mortalities and yield per recruit of the shrimp fish scad Alepes djedaba (Forskal) (F. Carangidae), from Abu Qir Bay, Eastern Alexandria, Egypt
El-Sayed, H.Kh.A.
Growth and population dynamics parameters of Alepes djedaba as an exotic carangid fish species from Red Sea into the Levant Basin of the Mediterranean Sea, were investigated. Fish samples were obtained from purse-seiners operating during the day time from Jan. to Dec. 2003 in Abu Qir Bay, Eastern Alexandria. The results obtained show that back-calculated lengths (based upon otolith readings) for the first; second and third age groups were 10.38; 15.4 and 19.32 cm TL respectively, the estimated Bertalanffy growth parameters were L∞=33.29 cm, K=0.2473 and t0= -0.51. The Length-weight relationship was represented by the formula: Log W=-1.9245+2.9762 Log L. Total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.85; 0.62 and 1.23 respectively. The exploitation rate (E) was found to be 56%. A Beverton and Holt yield per recruit model indicated that the maximium sustainable yield could 20.20 g at fishing mortality F= 1.6, while the current yield per recruit was 20.10 g at fishing mortality 1.23. The results proved that the purse-seine fishery of A. diedaba is over exploited in Abu-Qir Bay and requires to be managed.
2005-01-01T00:00:00ZChemical analysis of some macrophytes in Mariut and Edku lakes, Egypt
http://hdl.handle.net/1834/1244
Chemical analysis of some macrophytes in Mariut and Edku lakes, Egypt
El-Sarraf, W.M.
Results of the investigation carried out in Lakes Mariut and Edku revealed that the trace metals concentrations in ceratophyllum demersum is relatively higher than that in Potamogeton pectinatus. The protein and trace metals in macrophytes collected from unpolluted areas is lower thjan that form polluted ones. Eichhornia crassipes can have a restricted role for the treatment of lake water. In Lake Edku, the results of chemical composition of sediments agree with the previous studies. The trace metal content of C. demersum was higher than that of P. pectinatus. The higher organic carbon level was recorded in stems of submerged plants and in leaves of floating ones. On the other hand, the high concentration of trace metal was observed in leaves of submerged plants and the roots of floating plants. The epiphytes on C. demersum showed trace metal content relatively less than that of the substratum.
1995-01-01T00:00:00ZChemical composition of some marine algae from the Mediterranean Sea of Alexandria, Egypt
http://hdl.handle.net/1834/1243
Chemical composition of some marine algae from the Mediterranean Sea of Alexandria, Egypt
El-Sarraf, W.M.; El-Shaarawy, G.
No abstract is included
1994-01-01T00:00:00ZEffects of copper on photosynthesis activity and chlorophyll-a content of chaetoceros radicans schutt
http://hdl.handle.net/1834/1242
Effects of copper on photosynthesis activity and chlorophyll-a content of chaetoceros radicans schutt
Taha, O.E.; El-Sarraf, W.M.
Chaetoceros radicans was selected to test the effect of copper concentrations of 0.001, 0.005, 0.01, 0.05, 0.1 and 0.5 ppm for 6 days on the photosynthetic activity and chlorophyll-a content under laboratory conditions. The photosynthetic activity decreased with time of exposure and copper concentration. The control photosynthetic activity reached a maximum value at 120 hours and chlorophyll-a at 72 hours. Chaetoceros radicans cultures treated by copper showed a slight decrease in its photosynthetic activity and chlorophyll-a at levels 0.001 and 0.005 ppm, while they rapidly decreased at higher copper concentrations.
1995-01-01T00:00:00Z