Grey mullet (Mugil cephalus) rearing normative as a new species in Gomishan, Golestan Province

Grey Mullet (Mugil cephalus) is an important food fish species in the, Mugilidae which is able to adapt in a wide range of salinities and temperatures and is suitable for introduction of the species to freshwater, brackish, and brine waters for aquaculture. This study was implemented to determine appropriate normative of stocking density and initial weight ofMugil cephalus and also evaluate effects of these factors on the growth and feeding rates. Ten thousands of juveniles grey mullets (0.281±0.03 g 2.83±0.12 cm) were acquired from Mediterranean coastal waters of Egypt and were stocked in a quarter hectare of shrimp ponds in propagation and cultivation center of Gomishan, Golestan, for twenty- four months. Fish were stocked for first and second years at the density of 5000, 10000/ha and 2000, 2500/ha respectively. Mullets were fed by live foods and three concentrate diets in the first and second years of rearing, respectively. Recorded datashowed that the weights and lengths were different at the end of the first year with different densities (113.7±5.21 g and 21.1±0.21 cm (5000/ha) and 86.6±2.54 g and 19.6±1.02 cm (density= 10000/ha)). The highest weight in the second year was 476.6±0.23 g (density: 2000, initial weight: 115) and the lowest was 327±0.98 (density: 2000, initial weight: 80). The FCR at density of 5000 and 10000/ha were 3.4±0.08 and 3.9±0.05 respectively, indicating that density can effect on FCR rate. In the second year, the lowest FCR belonged to treatment 5 (density of 2500 and initial weight of 115). There was no significant difference in the survival rate and SGR during the two years of rearing. Rearing information about mullet is rare so the aim of this research was to determine some standards and introduce a normative for Golestan climatic condition.