The aims of the investigations were to estimate the biomass and the production of the macrozoobenthos and to know their season dynamics. Investigations were supported by Fishery's Foundation. Sediment chemical analysis showed that the macrozoobenthos biomass was determined by the quantity of the phosporus. Chironomid larvae formed the 70-90 per cent of benthos biomass in Keszthely basin.

Commercial fish landing at Abu Qir and Alanfoushy markets was the source of Siganus rivulatus and Siganus luridus sampled for food and feeding habits analysis. Food indices and food content were studies in stomach analyses of 1485 fishes

An experiment were conducted to evaluate The effect of feeding frequencies and stocking size on growth and feed conversion ratio (FCR) of rainbow trout (O. mykiss) in brackish water for 102 days. Three stocking sizes (10, 25 and 40 g/fish) of rainbow trout and three feeding frequencies (feeding fish twice, three times and four times per day) were examined as the same time. Fish were fed at a restricted feeding program according to the rainbow trout standard table in the definite times during the light period. The results showed that in the group with 10 g initial weight increasing the feeding frequency, some growth factors like final weight, daily growth, and weight gain. But the other factors such as food conversion rate (FCR) and specific growth rate (SGR) decrease. It means in this group (10 g) two times feeding per day is not enough for an acceptable growth rate. In the two other groups with (initial weight 25 and 40 g) although by increasing the feeding frequency, some growth factors a little increase but these differences in 95% level (p،ـ0.05) are not significant. Therefore in rainbow trout culture with initial weight at least 25 g two times feeding per day was enough. The results of carcasses analysis of fish, showed that by increasing the feeding frequency there were no significantly difference at 95% level between the body compositions in all of treatments. With connivance of feeding frequencies, the best FCR was in the group with 10 g initial body weight and there was not any significant difference in SGR. So according to the results, it suggests that fish should be stocked with 10 g initial body weight.

Carp of the initial individual weight about 1 kg were fed in cages with four kinds of extruded feeds differing in the lipid content (7.5-19.5 percentage). The main source of lipids was a poultry fat. The most favourable results of rearing were achieved while feed containing 15.3 percentage of lipids was used in carp feeding

An experiment on feeding preferences of the white sea-bass fingerlings (Lates calcarifer (Bloch)) fed with four different kinds of food; fresh fish meat mixed with one percent of vitamins, fish silage and living preys, in the circulation-water system (closed-type) was conducted. This was performed twice by using completely randomized design in sixteen fiber-glass tanks which could contain forty liters of brackish water to compare growth rate, survival rate and also to observe their behavior. The results show that the four different kinds of food used in the experiment had cannibalistic effects on these fingerlings which was the main cause of the low survival rate and the variation in size of the fingerlings. Those fed with living preys had low production. The fingerlings fed with fresh-fish meat had both low growth rate, low survival rate and also low production. This result occurred after nursing fingerlings for a certain period of time, and they had abnormal bones on the upper and lower jaws. The lowest growth rate and lowest production occurred in fingerlings fed with fish silage