Determination of the most suitable time for starting cultivation Pacific white shrimp (Litopenaeus vannamei Boone, 1931) in Gomishan Site (Golestan Province)

Regarding climate change, it is important to determine the most suitable time for starting its cultivation on the site of Gomishan shrimp. For this purpose, in range of air temperature (15-25°C), 21°C was chosen as the base temperature for Gomishan area. This experiment was conducted in 8 terrestrial ponds that were different of density (350000, 182000, 100000 ind/he and time of stocking; 18 Jun, 27 Jun, 4 Jul, 22 Jul) in 2012. Physico-chemical parameters and biometric data were two-weekly taken. The results showed that some of the parameters including pH, transparency, ammonia, nitrate, calcium, and potassium ions were sometimes out of the suitable range. The lowest final weight was 12.68 gr. in a pool with a density of 350,000 ind/he and the release time of June 28th with 127 days of breeding and the highest was 16.07 grams of the 100000 ind/he, it’s of June 19th during 128 days. The highest SGR% was observed in the pond stocking 182000 ind/he in early June. It seems, May 13th to May 23th are suitable time for starting shrimp cultivation on the site of Gomishan with higher density but it delay in starting cultivation, it is better lower density with larger postlarvae for reach to suitable weight.