وضعيت تغذيه بچه قره برون هاي رهاسازي شده به گرگانرود

Nutritional status of released Acipenser persicus fingerlings in Gorgan-roud

This study was carried out in two periods: 1377 and 1378. During two periods of this study in which Persian sturgeon juveniles were released, the results showed that those juveniles which selected the estuary for their living for a short period of two days, depending on the water salinity, they started to feed on the gammaridae and chiromidae a day after the released. The mentioned feed items are used as the main bait by these juveniles generally. At this time stomachs and guts of the juveniles have an average weight in the order of 4.30±1.70 and 6.90±4.90 mg approximately. The estimated condition factors of juveniles were 0.347±0.03. Stomachs and guts weights as well as the condition factors of the juveniles were higher at the beginning of the spring at the time of release than the end of the releasing period, and as closing to the end of the period the trend of decrease in weight was higher than the starting period. Considering the average water salinity that measured to be about 6.75±3.02 g/l, it seems that the time needed for juveniles to reach the sea from the point of their release, it takes about 6 hours or something near 3 hours per km. approximately.