The effect of density and stocking weight on growth rate and production of grey mullet (Mugil cephalus L.).

Around ten thousands fries of Striped grey mullet (Mugil cephalus) with average weight and length of 280
mg and 28.3 mm respectively, imported in March 2008 from Egypt. The wild fries collected from
surrounding natural waters of Alexandria.They stocked in four earthen ponds (each with 2500 m2) located at
the Gomishan shrimp educational centre at late march in 2008. At the first year of culture the densities were
5000 and 10000 individuals per hectare and each treatment with two replicates. At second year, densities
changed with 2000 and 2500 individuals per hectares and each of the treatments divided fishes with average
primary weights of 80 and 115 grams.They fed twice a day at 8 AM and 2 PM and the amount was 5-7
percents of the fish existent biomass in each ponds.After seven months culture period, the average weight
and length of fish in treatment 5000 ind./hec. were 113.7 gr and 21.1 cm respectively and in treatment 10000
ind./hec. the average weight and length were 86.6 gr and 19.6 cm respectively. At first year the average
survival rate in different treatments was 77 percent. The average FCR in treatments 5000 and 10000 ind./hec.
were 3.4 and 3.9 respectively.At second years after six months culture the average weights in pond no. 9
(with primary weight 115 gr and density 2000 ind./hec) , pond no. 10 (with primary weight 80 gr and density
2000 ind./hec) , pond no. 11 (with primary weight 115 gr and density 2500 ind./hec) and pond no. 12 (with
primary weight 80 gr and density 2500 ind./hec) calculated as 476.6 ,338.1, 366.5 and 440 gr respectively.
The average survival rate and FCR were 93 % and 3.1 respectively.