Three sampling stations were chosen along the lower reach section of AlSanawbarriver (Lattakia-Syria). In these stations, the freshwater molluscs were studied, environmentally and taxonomically, during the period 4/3/2012 – 4/8/2013.
In this resea
rch, I present the results of the environmental study on the Gastropod Valvatasaulcyiwhich was more abundant in the 3rd station; 5km of the estuary.
Ten mollusc species were identified; 8 belonging to Gastropoda (4 of Prosobranchia & 4 of Pulmonata) and 2 belonging to Bivalvia.
The chemical and physical properties of the water in the 3rd station were studied and the work was concentrated on Valvatasaulcyipopulation and structure, where samples were collected bimonthly during Spring, summer & autumn and monthly during winter. It was shown that reproduction of such species is continuous along the year, with 2 reproduction beaks: the more important one is spring beak and the less important one is autumn beak.
The population structure of the species was studied: shell dimensions were measured and the relationships were studied between height growth and breadth growth of the shell, and between the breadth growth and dry weight of the individual ….
This study was conducted to investigate the effect of abrupt and gradual acclimation
of Liza aurata fingerlings to fresh water and gradual acclimation to a selected salinity 3‰.
L.aurata fingerlings were collected directly from the sea and duplicat
e groups of 30
fingerlings were distributed after rest to glass aquaria (100 liter capacity). The first group
was acclimated abruptly to fresh water, the second gradually to fresh water, the third was
acclimated gradually to 3‰ and the last group was left as control in sea water. The
fingerlings were fed artificial diet (35% protein and 500 kcal GE/100g), twice a day to
satiation for 75 days.
