Determination of optional weight and length of Persian sturgeon's fingerling Acipenser persicus on the salinity index in the southern part of Caspian Sea

The Persian Sturgeon, Acipenser persicus is the most important sturgeon species in the southern part of the Caspian Sea and it provides 51% of Iran's caviar production. We were used five different age groups of the larvae (7, 17, 22, 28 and 33 days after yolk absorption) in 3 replicates. The larvae were all transferred at the same time to 27 liter aquarium holding 15 liter of water at different salinities (0.5, 7 and 9 ppt) and were provided with continuous aeration. Analysis of data showed that during early stages of life, age is an important factor for development of osmoregulatory organs. However, in later stages, weight and length play a vital role in this regard. The present study reveals that during post hatch and active feeding, in favorable environmental and rearing condition A. persicus fingerlings could be released into rivers and estuaries in Guilan province at an age of 33-35 days after yolk sac absorption and when they attain weight of 1.8-2.4g and length of 6.2-7.5cm.