The effect of eyestalk ablation on haemolymph osmotic and ionic concentrations during acute salinity exposure in the freshwater shrimp Macrobrachium olfersii (Wiegmann) (Crustacea,Decapoda)

The location, morphometry, climatic conditions, water balance, hydrology and hydrochemistry of lake Manzala were investigated.Mean annual salinity declined by about 82.7% since 1921, from 16.7 to 2.9% during 1985/86. The nutrient loading increased two or threefold over the past 20 years.These changes are attributed to an increase of the inflow of sewage and agricultural drainage water and restriction of water inflow at the Gamil Lake-Sea Connection since the late 1960's and early 1970's.