الفهرس 
Classification of Daphnia magna (Edmondson, 1963)Only 14 pages are availabe for public view
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Abstract
from Probit analysis of acute tests of Daphnia magna, it was found that 48-LC50 was 4.37 for low pH, 10.66 for high pH, 3.8‰ for NaCl solution, 3.9 ‰ for synthetic sea water and 4.5‰ for natural sea water.
from sublethal concentrations, long-term experiments were undertaken to determine the effect of different levels of temperature, pH and salinity (NaCl, synthetic sea water and natural sea water) on D. magna to detect the most suitable conditions for their survival, growth and reproduction rates under laboratory conditions It was concluded that these rates were high at temperatures range of 20-24°C with optimum at 22°C. It was observed that there is no number of progeny until the 21st day at temperatures ranged from 10-14°C. At investigated pH levels, it was detected that survival and growth rates decreased as pH decreased from 4.74 to 4.44 and by increasing pH from 10.13 to 10.55. It is clear that groups of daphnids reared at pH 8.33 (control) recorded the highest survival and growth rates. The maximum number of progeny per female were recorded for daphnids reared at acidic pH 4.66 corresponding to LC15 and alkaline pH; 10.13 (LC10). It is worth mentioning that great numbers of these neonates released weak, unhealthy and dead. However, control group recorded lower number of progeny per female comparing to those of acidic pH LC15 and alkaline pH LC10, but these neonates were in a healthy manner. Comparing the salinities studied it was found that, groups of D. magna reared in synthetic sea water at 0.44‰ (corresponding to LC10) showed the maximum length, specific growth rates and number of progeny per female. The biochemical composition was determined in the optimum conditions for D. magna at 22°C, pH 8.33 (control) and 0.44‰ synthetic sea water. Biochemical analysis revealed that D. magna contains 4.18 and 5.2 mg/100g wet weight protein and 1.09 and 1.15 g/100g wet weight Lipid, ash represented by 8.7 and 8.8%, moisture represented by 81 and 79% for groups reared in 0‰ (control) and 0.44‰ (LC10 synthetic sea water), respectively. Four essential amino acids were detected for D. magna reared in 0.44‰ synthetic sea water while for control group only two, lysine and phenylalanine. Fatty acids profile of D. magna showed four saturated fatty acids dominated by myristic acid (14:0). Moreover, nine unsaturated fatty acids (UFAs) were determined and the most abundant UFAs were in descending order; linoleic acid (18:2n-6), arachidonic acid (20:4n-6), palmitoleic acid (16:1n-7), oleic acid (18:1n-9), DHA (22:6n-3), myristolic acid (14:1n-6), EPA (20:5n-3), linolenic acid (18:3n-3) and erucic acid (22:1n-9). Total fatty acids were slightly higher for D. magna reared in concentration 0.44‰ S than those cultured in 0‰ S (control).